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High School Biology

Texas Bio TEKS

Don’t know - Sort of know - Know well

  • Stages of cell cycle, DNA replication and mitosis

  • Specialized cells such as roots, stems, and leaves of plants; and animal cells such as blood, muscle, and epithelium

  • describe the roles of DNA, ribonucleic acid (RNA), and environmental factors in cell differentiation

  • disruptions of the cell cycle lead to diseases such as cancer

  • purpose and process of transcription and translation using models of DNA and RNA

  • changes in DNA and evaluate the significance of these changes

  • predict possible outcomes of various genetic combinations such as monohybrid crosses, dihybrid crosses and non-Mendelian inheritance

  • recognize the significance of meiosis to sexual reproduction

  • evidence of common ancestry among groups is provided by the fossil record, biogeography, and homologies, including anatomical, molecular, and developmental

  • elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success

  • the relationship of natural selection to adaptation and to the development of diversity in and among species

  • effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation, and recombination

  • structures and functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic acids

  • compare the reactants and products of photosynthesis and cellular respiration in terms of energy and matter

  • role of enzymes

  • evidence regarding formation of simple organic molecules and their organization into long complex molecules having information such as the DNA molecule for self-replicating life

  • interactions that occur among systems that perform the functions of regulation, nutrient absorption, reproduction, and defense from injury or illness in animals

  • interactions that occur among systems that perform the functions of transport, reproduction, and response in plants - plant systems

  • levels of organization in biological systems and relate the levels to each other and to the whole system

  • Taxonomy

  • hierarchical classification system based on similarities and differences shared among groups

  • characteristics of taxonomic groups, including archaea, bacteria, protists, fungi, plants, and animals

  • role of internal feedback mechanisms in the maintenance of homeostasis

  • predation, parasitism, commensalism, mutualism

  • variations and adaptations of organisms in different ecosystem

  • flow of matter and energy through trophic levels using various models, including food chains, food webs, and ecological pyramids;

  • flow of matter through the carbon and nitrogen cycles and explain the consequences of disrupting these cycles

  • environmental change can impact ecosystem stability

Cells

Cell Theory

  • The cell is the smallest living unit in all organisms

  • All living things are made of cells

  • All cells come from other pre-existing cells

Prokaryotes: Uni-cellular, DNA located inside cytoplasm, no nucleus, no membrane bound organelles, contains DNA, cytoplasm, ribosomes, smaller than eukaryotes Examples: bacteria and archaea

Eukaryotes: Animal cells, plant cells, fungus cells, protists cells, cell wall, membrane bound organelles, multicellular, nucleus, larger than prokaryote cells

Both: DNA, ribosomes, cytoplasm, and cell membrane

Viruses: are not made of cells, they do not maintain homeostasis, they do not obtain and use energy and are thus not considered living.

  • Have a Capsid (protein coat)

  • Contain Nucleic Acid

Examples: HIV, Influenza, Chicken pox, Measles, Mumps, Polio, Common cold, and Rabies

Organelles and their functions:
  • Nucleus: Membrane bound organelle, contains the cells DNA

  • Rough ER: contains ribosomes; proteins are synthesized

  • Smooth ER: Phospholipids, fats, and steroids are synthesized

  • Ribosomes: location of protein synthesis; is mostly made of mRNA

  • Golgi Complex/body/apparatus: modifies, processes and sorts protein products from the ER

  • Mitochondria: POWER HOUSE OF THE CELL!! Main role is the production of ATP energy through cellular respiration

  • Plasma/Cell Membrane: Lipid bi-layer, surrounds the cell and is responsible for transport in/out of the cell

  • Cytoplasm: cell shape, material transport like genetic material and products for cellular respiration, and storage

  • Lysosome: Cell organelle filled with enzymes needed to break down certain materials in the cell

  • Cell Wall: Surrounds plant, fungal, and bacterial cells, provides strength and rigidity to the cell

  • Central Vacuole: stores water, dissolved substances, and wastes: also maintains correct water pressure within the cell

  • Chloroplast: carry out the process of photosynthesis

  • Flagella: Whip like tail used to move; found in some bacterial

    cells, sperm cells, some protists

  • Chromosomes: a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

Cell Division

Binary Fission: splits one cell into 2

Mitosis: happens in all body cells except reproductive

  • Starts with 1 cell ends with 2

  • 2 daughter cells look exactly like the original cell

  • Somatic: body cells

Meiosis: doesn’t happen to body cells but happens in gametes and plant spores

  • Meiosis is part of reproduction

  • 4 daughter cells each with ½ the number of chromosomes of the parent cell

DNA Inheritance

Heredity: passing traits down from one generation to the next

Gregor Mendel: father of genetics

Genes: codes for a specific trait

  • Alleles: variations of a trait

  • Homozygous: same (BB or bb)

  • Heterozygous: different (Bb)

  • Dominant: One variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene, usually represented by a uppercase letter (B)

  • Recessive: Is expressed only if both the alleles are homozygous and NOT dominant, usually represented by a lowercase letter (b)

Genotype: genetic description (Bb or bb)

Phenotype: physical features (Brown eyes/blue eyes)

Everyone has the same genes but they’re coed different which is why everyone is unique

Punnet Square: a ratio that is used to depict Mendel’s rules

P Generation: parent

F1: 1st generation

F2: 2nd generation

Mutations

Genetic Mutations: alterations that occur within a DNA sequence. They can cause diseases and conditions, but are also key in the development of new traits or even species!

Causes

Natural: mutations can occur during cell mitosis or meiosis when DNA is being copied

Environmental: mutations can be caused by environmental factors such as chemicals or from ionizing radiation from the sun

Types

Substitution: when one base is changed for another GCCTTAGAC → GCCTAAGAC

Insertion: when an extra base is added to the copy GCCTTAGAC → GCCTATAGAC

Deletion: when a base is removed from the copy GCCTTAGAC → GCCTAGAC

Effects

Beneficial: Mutations that have a positive effect on the organism

Neutral: Some mutations are neither harmful nor beneficial. The error does not have a measurable affect on the phenotype of the organism or the error can be repaired

Harmful: harmful mutations cause genetic disorders or cancer. Cystic fibrosis is due to a mutation in a single gene and it causes the body to produce a thick mucus in the lungs

Plant Specialized Cells

Leaves: Collect sunlight for photosynthesis, gas (O2/CO2) exchange through the stomata*

Stems: Hold up leaves and flowers, contains vascular tissue (xylem & phloem)*

Roots: Attach/anchor plant to the ground, absorb water and nutrients from the soil

Flowers: Seed-bearing structures, will sometimes produce fruit, attract pollinators to the plant

Cell Transport Systems * add pictures/diagrams

Osmosis: Diffusion of water through a selectively permeable membrane (like across a cell membrane)

Diffusion: Process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

Facilitated Diffusion: Movement of specific molecules across cell membranes through protein channels

Passive Transport: movement of materials without using energy

Active Transport: Energy-requiring process that moves materials across a cell membrane against a concentration difference.

CELL CYCLE

Interphase

Gap 1 phase

  • Cell grows larger

  • Cell copies organelles

S Phase

  • Cell makes a complete copy of DNA

  • Also duplicates centrosomes

Gap 2 phase

  • The cells grow more

  • Makes proteins and organelles

  • Prepares for mitosis

Mitotic Phase (or M phase)

*The information in this section is from Kahn Academy*

Cell divides its DNA and cytoplasm into 2 new cells

Mitosis

Prophase

  • Early Prophase:

    • Chromosomes begin to condense

    • The mitotic spindle forms - made of microtubules* - define mitotic spindle

    • The nucleolus disappears

  • Late Prophase/Prometaphase:

    • Chromosomes condense further

    • The nuclear envelope breaks down, this releases the chromosomes

    • Mitotic spindle grows more

    • Major organelles and the nuclear membrane dissolve

    • Microtubules (love these!) begin to “capture“/attach to chromosomes

Metaphase

  • The microtubules line all the chromosomes up at the metaphase plate

  • Before anaphase, the cell will check that all the chromosomes are at the metaphase plate with their kinetochores correctly attached to microtubules, this is called the spindle checkpoint and helps ensure that the sister chromatids will split evenly between the two daughter cells

Anaphase

  • The proteins that hold the sister chromatids together gets broken down allowing them to separate

  • Each, now single, chromosome is pulled towards opposite ends of the cell

  • The cell grows longer

Telophase

  • 2 new nuclei form

  • Nuclear membrane and nucleoli reappear

  • Chromosomes begin to decondense

Cytokinesis

  • Is the separating of the cells

  • Plant: the cell plate forms and separates the cell

All of these processes are driven by motor proteins. In mitosis, motor proteins carry chromosomes or other microtubules.

Meiosis

Meiosis l

  • Prophase l:

    • Chromosomes condense and pair up

    • They then perform a process called crossing over where they exchange parts of their DNA

  • Metaphase l:

    • Homologue* are lined up at the metaphase plate by microtubules

  • Anaphase l:

    • Homologues get pulled apart then moved to opposites sides of the cell

    • Sister chromatids stay together and are not pulled apart

  • Telophase l:

    • Chromosomes are at the separate ends of the cell

    • In some organisms, the nuclear membrane re-forms and the chromosomes decondense but not all

    • Cytokinesis also occurs during this phase

Meiosis ll

Cells that go into meiosis ll are cells that have already undergone meiosis l, these are Haploid cells

  • Prophase ll:

    • Chromosomes condense

    • the nuclear envelope breaks down, if needed

    • Centrosomes move apart

    • Spindle forms and begins capturing chromosomes

    • The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles

  • Metaphase ll:

    • Chromosomes line up at the metaphase plate

  • Anaphase ll:

    • Sister chromosomes separate

    • They get pulled to opposite poles

  • Telophase ll:

    • nuclear membranes form around each set of chromosomes

    • Chromosomes decondense

    • Cytokinesis splits the chromosome sets into new cells

The final product of these processes is four haploid cells with each chromosome having just one chromatid

DNA and Mechanisms of Genetics

PAIRINGS

DNA: Adenine - Thymine and Guanine - Cytosine

RNA: Adenine - Uracil and Guanine - Cytosine

Genetic Processes

Replication: DNA to DNA, occurs in the nucleus

Transcription: DNA to mRNA, occurs in the nucleus, mRNA then goes to the ribosome

Translation: mRNA to protein, occurs in the ribosome, rRNA and tRNA play a role in the process of translation.

Genetic Code

Molecular Genetics

  • Sometimes refers to a fundamental theory alleging that “Genes directs all life processes through the production of polypeptides.”

  • Polypeptides are the building blocks of proteins

  • Amino Acids are the building blocks of polypeptides

DNA Structure

DNA: Deoxyribonucleic acid is the molecule that carries genetic info for the development and functioning of an organism, 2 strands, found in all cells

RNA: Ribonucleic acid is a molecule that is present in the majority of living organisms and viruses, 1 strand

DNA stores the genetic code, RNA gets the code then takes it to where it’s needed

3 Parts of a Nucleotide

Nucleotide: building block of nucleic acids (DNA + RNA)

Part 1: Phosphate group

Part 2: Sugar - Deoxyribose (DNA) and Ribose (RNA)

Part 3: Nitrogen Bases - Adenine (A), Cytosine (C), Guanine (G), Thymine (T), and Uracil (U)- ATCG (DNA) and AUCG (RNA)

A pairs with T and C pairs with G, when not paired correctly it causes abnormalities

Nitrogen Bases

Adenine: Adenine is a purine base with 5 or 6 sided rings Abbreviation: A Pair: T

Thymine: Thymine is pyrimidines which are composed of a single six-sided ring Abbreviation: T Pair: A

Guanine: Guanine is a purine base with 5 or 6 sided rings Abbreviation: G Pair: C

Cytosine: cytosine are pyrimidines which are composed of single six-sided rings Abbreviation: C Pair: G

DNA

Function: Long term storage of genetic information

Structure: E-form double helix (whatever that means)

Composition: Adenine, guanine, cytosine, and thymine bases

Propagation: DNA is self-replicating

RNA

Function: used to transfer genetic information in organisms

Structure: A-form helix *

Composition: Adenine, guanine, cytosine and uracil bases

Propagation: it’s synthesized from DNA on an as-needed basis

Body Systems

Cells make up tissues, tissues make up organs, organs make up organ systems

Types of Tissues

Most organs contain all 4 types of tissue

Nervous Tissue

  • Helps with sensing stimuli

  • Processes & transmits information

  • Consistes of 2 main cells: neurons and glia

  • Neurons: basic functional unit of the nervous system

    • they generate electrical signals called conducted nerve impulses or action potentials which allow them to communicate information rapidly over long distances

  • Glia: act to support neuronal function

    • Brain tissue

    • Spinal chord tissue

    • Nerves

Muscle Tissue

  • Is needed for the structure of the body, ability to move, and pumping blood & food in digestive tract

  • The muscle cells have the proteins actin and myosin which allows them to contract

    • Cardiac Muscle

      • only found in the hearts walls

      • individual fibers allow them to contract in sync

    • Smooth Muscle

      • found in blood vessels, walls of the digestive tract, uterus, and urinary bladder

    • Skeletal Muscle

      • attached to bones by tendons

      • allows you to consciously control your movements

Epithelial Tissue

  • Consists of tightly packed sheets of cells that cover surfaces

  • Epithelial cells are polarized and have a top & bottom side called apical (top) and basal (bottom)

  • Cells are tightly packed to act as a barrier to the movement of fluids and harmful microbes inside the body

    • Lining of GI tract organs and other hollow organs - find examples

    • Skins surface (epidermis)

Connective Tissue

  • Supports and connects tissues

    • fat and other soft padding tissue

    • bone

    • tendons

Major Organ Systems

Cardiovascular: transports oxygen, nutrients, and other substances to cells then transports wastes, carbon dioxide, etc. away from cells; can also help with stabilizing body temperature and PH levels

Organs, tissues, & structures involved: heart, blood, and blood vessels

Lymphatic: defends against infections & disease, transfers lymph between tissues & blood stream

Organs, tissues, & structures involved: lymph, lymph nodes, lymph vessels

Digestive: processes food, absorbs nutrients, minerals, vitamins and water

Organs, tissues, & structures involved: mouth, salivary glands, esophagus, stomach, liver, gallbladder, exocrine pancreas, small & big intestines

Endocrine: provides communication within the body via hormones and directs long-term change in other organ systems to maintain homeostasis

Organs, tissues, & structures involved: pituitary, pineal, thyroid, parathyroids, testes and ovaries

Integumentary: provides protection from injury and fluid loss, provides physical defense against microorganisms, involved in temperature control

Organs, tissues, & structures involved: skin, hair, nails

Muscular: provides movement, support and heat protection

Organs, tissues, & structures involved: skeletal, cardiac, smooth muscles

Nervous: collects, transfers, and processes information, directs short-term change in other organ systems

Organs, tissues, & structures involved: Brain, spinal chord, nerves, sensory organs

Reproductive: produces gametes and sex hormones; produces offspring

Organs, tissues, & structures involved:

Skeletal: supports & protects soft tissues of the body; movement at joints; produces blood cells; stores minerals

Organs, tissues, & structures involved: bones, cartilage, joints, tendons, ligaments

Urinary: removes excess water, salts, waste products from the blood & body; controls PH

Organs, tissues, & structures involved: kidneys, uretes, urinary bladder, uretha

Immune: defends against microbial pathogens - disease causing agents - & other diseases

Organs, tissues, & structures involved: Leukocytes, tonsils, denoids, thymus and spleen

Theory of Evolution

Evolution: a gradual change in the characteristics of a species over time

Species: a population of organisms whose members look alike and can interbreed (reproduce) fertile offspring

Charles Darwin: founder of modern evolutionary theory which he discovered by studying finches. Wrote the book “On the Origin of Species.”

On the Origin of Species: the dominant scientific explanation of diversification in nature

Natural Selection: mechanisms for changes in populations when organisms with favorable traits survive, reproduce, and pass down favorable traits to the next generation

Evidence for Evolution

  • All living things contain similar DNA, RNA, and proteins

  • Comparing DNA sequences to determine if the 2 organisms are closely related

  • The relationship can be used to create evolutionary pathways

  • Fossils and adaptions

Fossils

  • Preserved remains from once living things, we look at fossils to see evolution

  • Fossils have found many simpler life forms that existed in earth’s early history

  • The oldest fossils found are bacteria from 3.8 billion years ago

  • Paleontologist: someone who studies fossil evidence

Adaptations

  • Adaptations are evidence that support organic evolution

  • 2 types of adaptations: anatomical and physiological

  • Anatomical adaptations: happen anatomically

  • Physiological adaptations: an internal body process to regulate and maintain homeostasis for an organism to survive in the environment in which it exists

  • Homologous structures: same structure but different function, indicates a common ancestor

  • Analogous structures: have a similar function but different structure

  • Mimicry enables an organism to copy what another animal looks like, this can be so it doesn’t get eaten

  • Camouflage: structural adaptation that lets an organism blend in with its surroundings

Vestigial Structures

  • Structures like human appendix and the eyes of a cave fish

  • These structures support the theory of evolution because it shows structural changes over time

  • A feature inherited from an ancestor that no longer has a purpose

Ecology

Ecology: the study of ecosystems

Ecosystems: a system where the biotic components interact with each other and with abiotic components in order to sustain life

Biotic Components: living factors such as animals, plants, fungi and decomposers

Abiotic: non-living factors such as sunlight, water, soil. temperature, wind, etc.

Types of Ecosystems

1) Terrestrial Ecosystems: based on land

2) Aquatic Ecosystems: based in water

  • Marine Ecosystems have freshwater

  • Freshwater ecosystems have freshwater

3) Natural Ecosystems: NOT designed or managed by humans - higher biodiversity

4) Artificial Ecosystems: ARE designed and managed by humans - lower biodiversity

Biodiversity: a measure of the # of different types of organisms in an ecosystem - the lower the biodiversity the greater the impact of the organisms

Lower biodiversity makes an ecosystem weaker

Higher Biodiversity makes an ecosystem stronger

Hot Spots: geographic regions with significant biodiversity under threat by humans - 36 currently identified

  • As humans advance more we are affecting more and more ecosystems

Habitat: the natural environment where a species live and depend on to meet all of its needs

Ecological Niche: the specific role a species performs in its ecosystems

  • Example: The ecological niche of a deer is being a herbivore and provides food for predators as well as carrion for scavenger

  • Niches can overlap, but are never exactly the same, this decreases competition, if they played the same role one would die of or adapt because of competition

Cladogram: a diagram that shows/provides evidence for evolution using evolutionary pathways

  • Organisms to the right have more in common with one another

  • ←Left: less exclusive, less specific

  • → Right: more exclusive, more specific

Biomolecules

Monosaccharides:

  • Primary function/role is to provide a source of energy for a cell

  • Is a sugar

  • Most common is glucose

  • Are broken down during cellular respiration to produce ATP energy

Carbohydrates

Elements/chemical formula: Carbon, hydrogen, oxygen

Function: Main source of energy for cell processes. Carbohydrates contain sugars that are necessary for many energy creating cell processes. A common sugar being glucose which is used in the ATP process.

Monomer (building block): Monosaccharides

Polymer (what it makes): polysaccharides, starch in plants, and glycogen in animals

Examples: Glucose, fructose

Extra info: Sugars end in -ose

Proteins

Elements/chemical formula: Carbon, hydrogen, oxygen and nitrogen

Function:

  • Bones and muscles

  • transport materials in and out of cells

  • controls rate of chemical reactions

  • regulates

  • fights diseases

Monomer: amino acids

Polymer: protein/polypeptide chain

Examples: meat, eggs,beans, soy, nuts, peanut butter, and enzymes

Other: One of the most important biomolecules, enzymes usually end in -ase

Lipids

Elements/chemical formula: Carbon, hydrogen, oxygen

Function:

  • Building block of biological membranes

  • long-term memory storage

  • makes up biological membranes like the phospholipids bi-layer

  • Makes coverings waterproof

  • Stores energy

  • insulation/cushioning

No true monomer or polymer! Does usually contain glycerol and fatty acid chains

Examples: Fats, oils, waxes, and biological membranes such as cholesterol

Other: Does NOT dissolve in water

Nucleic Acids

Elements/chemical formula: carbon, nitrogen, oxygen, phosphorus, and hydrogen

Function: Stores and transmits genetic information, codes for proteins

Monomer: Nucleotides (sugar, phosphate group and nitrogen base)

Polymer: Nucleic Acid

Examples: DNA, RNA, ATP

Monohybrid crosses, dihybrid crosses and non-Mendelian inheritance

Monohybrid Cross

  • Monohybrid cross happens when 2 of the organism with contrasting variations at a particular genetic locus? are crossed

  • The monohybrid cross shows Mendels law of dominance

  • A monohybrid cross involves the inheritance of a single gene or trait by crossing individual with differing alleles for that gene; this shows Mendels law of dominance

  • Mendel crosses 2 homologous traits and forms a heterozygous trait which is known as a monohybrid cross of the inheritance of a single gene

Dihybrid Cross

  • A dihybrid cross is a breeding experiment between 2 organisms which are identical hybrids for 2 traits

  • A cross between 2 organisms which are identical hybrids for 2 traits

  • 1 parent has homozygous dominant allele while the other has homozygous recessive

Non-Mendelian Inheritance

People in Biology

Rosalind Franklin: worked with Maurice Wilkins to work on X-ray crystallography. Helped to discover DNA’s helical structure

Maurice Wilkins: X-ray diffraction helped reveal the helical nature of DNA.

Erwin Chargaff: Discovered that DNA nucleotides were composed of 50% purines and 50% pyrimidines, which lead to the base-pairing

rules.

James Watson and Francis Crick: Used the works of other scientists to deduce that DNA’s shape was a double helix.

Vocab

  • Hypotonic

  • Hypertonic

  • Isotonic

  • Microtubules:

  • Mitotic Spindle:

  • Metaphase plate: not a specific structure just the area where the chromosomes line up during metaphase

  • Centromeres: the regions of DNA where the sister chromatids are most tightly connected

  • Gametes:

  • Somatic:

  • Diploid:

  • Haploid: have just one chromosome from each homologue pair but their chromosomes still consist of two sister chromatids

  • Monomer:

  • Polymer:

Resources

Cell Cycle - Kahn Academy

Meiosis - Kahn Academy

Mitosis - Kahn Academy

Mechanisms of Genetics

Cell Structure and Function

Biology Crash Course

Kahn Academy High School Biology

Kahn Academy AP/College Biology

Bioninja - covers IB

AT

High School Biology

Texas Bio TEKS

Don’t know - Sort of know - Know well

  • Stages of cell cycle, DNA replication and mitosis

  • Specialized cells such as roots, stems, and leaves of plants; and animal cells such as blood, muscle, and epithelium

  • describe the roles of DNA, ribonucleic acid (RNA), and environmental factors in cell differentiation

  • disruptions of the cell cycle lead to diseases such as cancer

  • purpose and process of transcription and translation using models of DNA and RNA

  • changes in DNA and evaluate the significance of these changes

  • predict possible outcomes of various genetic combinations such as monohybrid crosses, dihybrid crosses and non-Mendelian inheritance

  • recognize the significance of meiosis to sexual reproduction

  • evidence of common ancestry among groups is provided by the fossil record, biogeography, and homologies, including anatomical, molecular, and developmental

  • elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success

  • the relationship of natural selection to adaptation and to the development of diversity in and among species

  • effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation, and recombination

  • structures and functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic acids

  • compare the reactants and products of photosynthesis and cellular respiration in terms of energy and matter

  • role of enzymes

  • evidence regarding formation of simple organic molecules and their organization into long complex molecules having information such as the DNA molecule for self-replicating life

  • interactions that occur among systems that perform the functions of regulation, nutrient absorption, reproduction, and defense from injury or illness in animals

  • interactions that occur among systems that perform the functions of transport, reproduction, and response in plants - plant systems

  • levels of organization in biological systems and relate the levels to each other and to the whole system

  • Taxonomy

  • hierarchical classification system based on similarities and differences shared among groups

  • characteristics of taxonomic groups, including archaea, bacteria, protists, fungi, plants, and animals

  • role of internal feedback mechanisms in the maintenance of homeostasis

  • predation, parasitism, commensalism, mutualism

  • variations and adaptations of organisms in different ecosystem

  • flow of matter and energy through trophic levels using various models, including food chains, food webs, and ecological pyramids;

  • flow of matter through the carbon and nitrogen cycles and explain the consequences of disrupting these cycles

  • environmental change can impact ecosystem stability

Cells

Cell Theory

  • The cell is the smallest living unit in all organisms

  • All living things are made of cells

  • All cells come from other pre-existing cells

Prokaryotes: Uni-cellular, DNA located inside cytoplasm, no nucleus, no membrane bound organelles, contains DNA, cytoplasm, ribosomes, smaller than eukaryotes Examples: bacteria and archaea

Eukaryotes: Animal cells, plant cells, fungus cells, protists cells, cell wall, membrane bound organelles, multicellular, nucleus, larger than prokaryote cells

Both: DNA, ribosomes, cytoplasm, and cell membrane

Viruses: are not made of cells, they do not maintain homeostasis, they do not obtain and use energy and are thus not considered living.

  • Have a Capsid (protein coat)

  • Contain Nucleic Acid

Examples: HIV, Influenza, Chicken pox, Measles, Mumps, Polio, Common cold, and Rabies

Organelles and their functions:
  • Nucleus: Membrane bound organelle, contains the cells DNA

  • Rough ER: contains ribosomes; proteins are synthesized

  • Smooth ER: Phospholipids, fats, and steroids are synthesized

  • Ribosomes: location of protein synthesis; is mostly made of mRNA

  • Golgi Complex/body/apparatus: modifies, processes and sorts protein products from the ER

  • Mitochondria: POWER HOUSE OF THE CELL!! Main role is the production of ATP energy through cellular respiration

  • Plasma/Cell Membrane: Lipid bi-layer, surrounds the cell and is responsible for transport in/out of the cell

  • Cytoplasm: cell shape, material transport like genetic material and products for cellular respiration, and storage

  • Lysosome: Cell organelle filled with enzymes needed to break down certain materials in the cell

  • Cell Wall: Surrounds plant, fungal, and bacterial cells, provides strength and rigidity to the cell

  • Central Vacuole: stores water, dissolved substances, and wastes: also maintains correct water pressure within the cell

  • Chloroplast: carry out the process of photosynthesis

  • Flagella: Whip like tail used to move; found in some bacterial

    cells, sperm cells, some protists

  • Chromosomes: a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

Cell Division

Binary Fission: splits one cell into 2

Mitosis: happens in all body cells except reproductive

  • Starts with 1 cell ends with 2

  • 2 daughter cells look exactly like the original cell

  • Somatic: body cells

Meiosis: doesn’t happen to body cells but happens in gametes and plant spores

  • Meiosis is part of reproduction

  • 4 daughter cells each with ½ the number of chromosomes of the parent cell

DNA Inheritance

Heredity: passing traits down from one generation to the next

Gregor Mendel: father of genetics

Genes: codes for a specific trait

  • Alleles: variations of a trait

  • Homozygous: same (BB or bb)

  • Heterozygous: different (Bb)

  • Dominant: One variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene, usually represented by a uppercase letter (B)

  • Recessive: Is expressed only if both the alleles are homozygous and NOT dominant, usually represented by a lowercase letter (b)

Genotype: genetic description (Bb or bb)

Phenotype: physical features (Brown eyes/blue eyes)

Everyone has the same genes but they’re coed different which is why everyone is unique

Punnet Square: a ratio that is used to depict Mendel’s rules

P Generation: parent

F1: 1st generation

F2: 2nd generation

Mutations

Genetic Mutations: alterations that occur within a DNA sequence. They can cause diseases and conditions, but are also key in the development of new traits or even species!

Causes

Natural: mutations can occur during cell mitosis or meiosis when DNA is being copied

Environmental: mutations can be caused by environmental factors such as chemicals or from ionizing radiation from the sun

Types

Substitution: when one base is changed for another GCCTTAGAC → GCCTAAGAC

Insertion: when an extra base is added to the copy GCCTTAGAC → GCCTATAGAC

Deletion: when a base is removed from the copy GCCTTAGAC → GCCTAGAC

Effects

Beneficial: Mutations that have a positive effect on the organism

Neutral: Some mutations are neither harmful nor beneficial. The error does not have a measurable affect on the phenotype of the organism or the error can be repaired

Harmful: harmful mutations cause genetic disorders or cancer. Cystic fibrosis is due to a mutation in a single gene and it causes the body to produce a thick mucus in the lungs

Plant Specialized Cells

Leaves: Collect sunlight for photosynthesis, gas (O2/CO2) exchange through the stomata*

Stems: Hold up leaves and flowers, contains vascular tissue (xylem & phloem)*

Roots: Attach/anchor plant to the ground, absorb water and nutrients from the soil

Flowers: Seed-bearing structures, will sometimes produce fruit, attract pollinators to the plant

Cell Transport Systems * add pictures/diagrams

Osmosis: Diffusion of water through a selectively permeable membrane (like across a cell membrane)

Diffusion: Process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

Facilitated Diffusion: Movement of specific molecules across cell membranes through protein channels

Passive Transport: movement of materials without using energy

Active Transport: Energy-requiring process that moves materials across a cell membrane against a concentration difference.

CELL CYCLE

Interphase

Gap 1 phase

  • Cell grows larger

  • Cell copies organelles

S Phase

  • Cell makes a complete copy of DNA

  • Also duplicates centrosomes

Gap 2 phase

  • The cells grow more

  • Makes proteins and organelles

  • Prepares for mitosis

Mitotic Phase (or M phase)

*The information in this section is from Kahn Academy*

Cell divides its DNA and cytoplasm into 2 new cells

Mitosis

Prophase

  • Early Prophase:

    • Chromosomes begin to condense

    • The mitotic spindle forms - made of microtubules* - define mitotic spindle

    • The nucleolus disappears

  • Late Prophase/Prometaphase:

    • Chromosomes condense further

    • The nuclear envelope breaks down, this releases the chromosomes

    • Mitotic spindle grows more

    • Major organelles and the nuclear membrane dissolve

    • Microtubules (love these!) begin to “capture“/attach to chromosomes

Metaphase

  • The microtubules line all the chromosomes up at the metaphase plate

  • Before anaphase, the cell will check that all the chromosomes are at the metaphase plate with their kinetochores correctly attached to microtubules, this is called the spindle checkpoint and helps ensure that the sister chromatids will split evenly between the two daughter cells

Anaphase

  • The proteins that hold the sister chromatids together gets broken down allowing them to separate

  • Each, now single, chromosome is pulled towards opposite ends of the cell

  • The cell grows longer

Telophase

  • 2 new nuclei form

  • Nuclear membrane and nucleoli reappear

  • Chromosomes begin to decondense

Cytokinesis

  • Is the separating of the cells

  • Plant: the cell plate forms and separates the cell

All of these processes are driven by motor proteins. In mitosis, motor proteins carry chromosomes or other microtubules.

Meiosis

Meiosis l

  • Prophase l:

    • Chromosomes condense and pair up

    • They then perform a process called crossing over where they exchange parts of their DNA

  • Metaphase l:

    • Homologue* are lined up at the metaphase plate by microtubules

  • Anaphase l:

    • Homologues get pulled apart then moved to opposites sides of the cell

    • Sister chromatids stay together and are not pulled apart

  • Telophase l:

    • Chromosomes are at the separate ends of the cell

    • In some organisms, the nuclear membrane re-forms and the chromosomes decondense but not all

    • Cytokinesis also occurs during this phase

Meiosis ll

Cells that go into meiosis ll are cells that have already undergone meiosis l, these are Haploid cells

  • Prophase ll:

    • Chromosomes condense

    • the nuclear envelope breaks down, if needed

    • Centrosomes move apart

    • Spindle forms and begins capturing chromosomes

    • The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles

  • Metaphase ll:

    • Chromosomes line up at the metaphase plate

  • Anaphase ll:

    • Sister chromosomes separate

    • They get pulled to opposite poles

  • Telophase ll:

    • nuclear membranes form around each set of chromosomes

    • Chromosomes decondense

    • Cytokinesis splits the chromosome sets into new cells

The final product of these processes is four haploid cells with each chromosome having just one chromatid

DNA and Mechanisms of Genetics

PAIRINGS

DNA: Adenine - Thymine and Guanine - Cytosine

RNA: Adenine - Uracil and Guanine - Cytosine

Genetic Processes

Replication: DNA to DNA, occurs in the nucleus

Transcription: DNA to mRNA, occurs in the nucleus, mRNA then goes to the ribosome

Translation: mRNA to protein, occurs in the ribosome, rRNA and tRNA play a role in the process of translation.

Genetic Code

Molecular Genetics

  • Sometimes refers to a fundamental theory alleging that “Genes directs all life processes through the production of polypeptides.”

  • Polypeptides are the building blocks of proteins

  • Amino Acids are the building blocks of polypeptides

DNA Structure

DNA: Deoxyribonucleic acid is the molecule that carries genetic info for the development and functioning of an organism, 2 strands, found in all cells

RNA: Ribonucleic acid is a molecule that is present in the majority of living organisms and viruses, 1 strand

DNA stores the genetic code, RNA gets the code then takes it to where it’s needed

3 Parts of a Nucleotide

Nucleotide: building block of nucleic acids (DNA + RNA)

Part 1: Phosphate group

Part 2: Sugar - Deoxyribose (DNA) and Ribose (RNA)

Part 3: Nitrogen Bases - Adenine (A), Cytosine (C), Guanine (G), Thymine (T), and Uracil (U)- ATCG (DNA) and AUCG (RNA)

A pairs with T and C pairs with G, when not paired correctly it causes abnormalities

Nitrogen Bases

Adenine: Adenine is a purine base with 5 or 6 sided rings Abbreviation: A Pair: T

Thymine: Thymine is pyrimidines which are composed of a single six-sided ring Abbreviation: T Pair: A

Guanine: Guanine is a purine base with 5 or 6 sided rings Abbreviation: G Pair: C

Cytosine: cytosine are pyrimidines which are composed of single six-sided rings Abbreviation: C Pair: G

DNA

Function: Long term storage of genetic information

Structure: E-form double helix (whatever that means)

Composition: Adenine, guanine, cytosine, and thymine bases

Propagation: DNA is self-replicating

RNA

Function: used to transfer genetic information in organisms

Structure: A-form helix *

Composition: Adenine, guanine, cytosine and uracil bases

Propagation: it’s synthesized from DNA on an as-needed basis

Body Systems

Cells make up tissues, tissues make up organs, organs make up organ systems

Types of Tissues

Most organs contain all 4 types of tissue

Nervous Tissue

  • Helps with sensing stimuli

  • Processes & transmits information

  • Consistes of 2 main cells: neurons and glia

  • Neurons: basic functional unit of the nervous system

    • they generate electrical signals called conducted nerve impulses or action potentials which allow them to communicate information rapidly over long distances

  • Glia: act to support neuronal function

    • Brain tissue

    • Spinal chord tissue

    • Nerves

Muscle Tissue

  • Is needed for the structure of the body, ability to move, and pumping blood & food in digestive tract

  • The muscle cells have the proteins actin and myosin which allows them to contract

    • Cardiac Muscle

      • only found in the hearts walls

      • individual fibers allow them to contract in sync

    • Smooth Muscle

      • found in blood vessels, walls of the digestive tract, uterus, and urinary bladder

    • Skeletal Muscle

      • attached to bones by tendons

      • allows you to consciously control your movements

Epithelial Tissue

  • Consists of tightly packed sheets of cells that cover surfaces

  • Epithelial cells are polarized and have a top & bottom side called apical (top) and basal (bottom)

  • Cells are tightly packed to act as a barrier to the movement of fluids and harmful microbes inside the body

    • Lining of GI tract organs and other hollow organs - find examples

    • Skins surface (epidermis)

Connective Tissue

  • Supports and connects tissues

    • fat and other soft padding tissue

    • bone

    • tendons

Major Organ Systems

Cardiovascular: transports oxygen, nutrients, and other substances to cells then transports wastes, carbon dioxide, etc. away from cells; can also help with stabilizing body temperature and PH levels

Organs, tissues, & structures involved: heart, blood, and blood vessels

Lymphatic: defends against infections & disease, transfers lymph between tissues & blood stream

Organs, tissues, & structures involved: lymph, lymph nodes, lymph vessels

Digestive: processes food, absorbs nutrients, minerals, vitamins and water

Organs, tissues, & structures involved: mouth, salivary glands, esophagus, stomach, liver, gallbladder, exocrine pancreas, small & big intestines

Endocrine: provides communication within the body via hormones and directs long-term change in other organ systems to maintain homeostasis

Organs, tissues, & structures involved: pituitary, pineal, thyroid, parathyroids, testes and ovaries

Integumentary: provides protection from injury and fluid loss, provides physical defense against microorganisms, involved in temperature control

Organs, tissues, & structures involved: skin, hair, nails

Muscular: provides movement, support and heat protection

Organs, tissues, & structures involved: skeletal, cardiac, smooth muscles

Nervous: collects, transfers, and processes information, directs short-term change in other organ systems

Organs, tissues, & structures involved: Brain, spinal chord, nerves, sensory organs

Reproductive: produces gametes and sex hormones; produces offspring

Organs, tissues, & structures involved:

Skeletal: supports & protects soft tissues of the body; movement at joints; produces blood cells; stores minerals

Organs, tissues, & structures involved: bones, cartilage, joints, tendons, ligaments

Urinary: removes excess water, salts, waste products from the blood & body; controls PH

Organs, tissues, & structures involved: kidneys, uretes, urinary bladder, uretha

Immune: defends against microbial pathogens - disease causing agents - & other diseases

Organs, tissues, & structures involved: Leukocytes, tonsils, denoids, thymus and spleen

Theory of Evolution

Evolution: a gradual change in the characteristics of a species over time

Species: a population of organisms whose members look alike and can interbreed (reproduce) fertile offspring

Charles Darwin: founder of modern evolutionary theory which he discovered by studying finches. Wrote the book “On the Origin of Species.”

On the Origin of Species: the dominant scientific explanation of diversification in nature

Natural Selection: mechanisms for changes in populations when organisms with favorable traits survive, reproduce, and pass down favorable traits to the next generation

Evidence for Evolution

  • All living things contain similar DNA, RNA, and proteins

  • Comparing DNA sequences to determine if the 2 organisms are closely related

  • The relationship can be used to create evolutionary pathways

  • Fossils and adaptions

Fossils

  • Preserved remains from once living things, we look at fossils to see evolution

  • Fossils have found many simpler life forms that existed in earth’s early history

  • The oldest fossils found are bacteria from 3.8 billion years ago

  • Paleontologist: someone who studies fossil evidence

Adaptations

  • Adaptations are evidence that support organic evolution

  • 2 types of adaptations: anatomical and physiological

  • Anatomical adaptations: happen anatomically

  • Physiological adaptations: an internal body process to regulate and maintain homeostasis for an organism to survive in the environment in which it exists

  • Homologous structures: same structure but different function, indicates a common ancestor

  • Analogous structures: have a similar function but different structure

  • Mimicry enables an organism to copy what another animal looks like, this can be so it doesn’t get eaten

  • Camouflage: structural adaptation that lets an organism blend in with its surroundings

Vestigial Structures

  • Structures like human appendix and the eyes of a cave fish

  • These structures support the theory of evolution because it shows structural changes over time

  • A feature inherited from an ancestor that no longer has a purpose

Ecology

Ecology: the study of ecosystems

Ecosystems: a system where the biotic components interact with each other and with abiotic components in order to sustain life

Biotic Components: living factors such as animals, plants, fungi and decomposers

Abiotic: non-living factors such as sunlight, water, soil. temperature, wind, etc.

Types of Ecosystems

1) Terrestrial Ecosystems: based on land

2) Aquatic Ecosystems: based in water

  • Marine Ecosystems have freshwater

  • Freshwater ecosystems have freshwater

3) Natural Ecosystems: NOT designed or managed by humans - higher biodiversity

4) Artificial Ecosystems: ARE designed and managed by humans - lower biodiversity

Biodiversity: a measure of the # of different types of organisms in an ecosystem - the lower the biodiversity the greater the impact of the organisms

Lower biodiversity makes an ecosystem weaker

Higher Biodiversity makes an ecosystem stronger

Hot Spots: geographic regions with significant biodiversity under threat by humans - 36 currently identified

  • As humans advance more we are affecting more and more ecosystems

Habitat: the natural environment where a species live and depend on to meet all of its needs

Ecological Niche: the specific role a species performs in its ecosystems

  • Example: The ecological niche of a deer is being a herbivore and provides food for predators as well as carrion for scavenger

  • Niches can overlap, but are never exactly the same, this decreases competition, if they played the same role one would die of or adapt because of competition

Cladogram: a diagram that shows/provides evidence for evolution using evolutionary pathways

  • Organisms to the right have more in common with one another

  • ←Left: less exclusive, less specific

  • → Right: more exclusive, more specific

Biomolecules

Monosaccharides:

  • Primary function/role is to provide a source of energy for a cell

  • Is a sugar

  • Most common is glucose

  • Are broken down during cellular respiration to produce ATP energy

Carbohydrates

Elements/chemical formula: Carbon, hydrogen, oxygen

Function: Main source of energy for cell processes. Carbohydrates contain sugars that are necessary for many energy creating cell processes. A common sugar being glucose which is used in the ATP process.

Monomer (building block): Monosaccharides

Polymer (what it makes): polysaccharides, starch in plants, and glycogen in animals

Examples: Glucose, fructose

Extra info: Sugars end in -ose

Proteins

Elements/chemical formula: Carbon, hydrogen, oxygen and nitrogen

Function:

  • Bones and muscles

  • transport materials in and out of cells

  • controls rate of chemical reactions

  • regulates

  • fights diseases

Monomer: amino acids

Polymer: protein/polypeptide chain

Examples: meat, eggs,beans, soy, nuts, peanut butter, and enzymes

Other: One of the most important biomolecules, enzymes usually end in -ase

Lipids

Elements/chemical formula: Carbon, hydrogen, oxygen

Function:

  • Building block of biological membranes

  • long-term memory storage

  • makes up biological membranes like the phospholipids bi-layer

  • Makes coverings waterproof

  • Stores energy

  • insulation/cushioning

No true monomer or polymer! Does usually contain glycerol and fatty acid chains

Examples: Fats, oils, waxes, and biological membranes such as cholesterol

Other: Does NOT dissolve in water

Nucleic Acids

Elements/chemical formula: carbon, nitrogen, oxygen, phosphorus, and hydrogen

Function: Stores and transmits genetic information, codes for proteins

Monomer: Nucleotides (sugar, phosphate group and nitrogen base)

Polymer: Nucleic Acid

Examples: DNA, RNA, ATP

Monohybrid crosses, dihybrid crosses and non-Mendelian inheritance

Monohybrid Cross

  • Monohybrid cross happens when 2 of the organism with contrasting variations at a particular genetic locus? are crossed

  • The monohybrid cross shows Mendels law of dominance

  • A monohybrid cross involves the inheritance of a single gene or trait by crossing individual with differing alleles for that gene; this shows Mendels law of dominance

  • Mendel crosses 2 homologous traits and forms a heterozygous trait which is known as a monohybrid cross of the inheritance of a single gene

Dihybrid Cross

  • A dihybrid cross is a breeding experiment between 2 organisms which are identical hybrids for 2 traits

  • A cross between 2 organisms which are identical hybrids for 2 traits

  • 1 parent has homozygous dominant allele while the other has homozygous recessive

Non-Mendelian Inheritance

People in Biology

Rosalind Franklin: worked with Maurice Wilkins to work on X-ray crystallography. Helped to discover DNA’s helical structure

Maurice Wilkins: X-ray diffraction helped reveal the helical nature of DNA.

Erwin Chargaff: Discovered that DNA nucleotides were composed of 50% purines and 50% pyrimidines, which lead to the base-pairing

rules.

James Watson and Francis Crick: Used the works of other scientists to deduce that DNA’s shape was a double helix.

Vocab

  • Hypotonic

  • Hypertonic

  • Isotonic

  • Microtubules:

  • Mitotic Spindle:

  • Metaphase plate: not a specific structure just the area where the chromosomes line up during metaphase

  • Centromeres: the regions of DNA where the sister chromatids are most tightly connected

  • Gametes:

  • Somatic:

  • Diploid:

  • Haploid: have just one chromosome from each homologue pair but their chromosomes still consist of two sister chromatids

  • Monomer:

  • Polymer:

Resources

Cell Cycle - Kahn Academy

Meiosis - Kahn Academy

Mitosis - Kahn Academy

Mechanisms of Genetics

Cell Structure and Function

Biology Crash Course

Kahn Academy High School Biology

Kahn Academy AP/College Biology

Bioninja - covers IB