Studied by 8 people
Cell Theory
All living things are made of cells All cells come from already existing cells Cells are the most basic unit of life
Euakaryotes
Plant Cells and Animal cells (multicellular organism
Prokaryotes
Bacteria (unicellular organism)
Difference between Eukaryotes and Prokaryotes
Eukaryotes are much more complex due to the presence of membrane bound organelles
Animal Cells vs Plant Cells (differences)
Plant cells have a cell membrane and a cell wall Plants have both mitochondria and chloroplasts Plants have a large central Vacuole Animal Cells have centrioles (contain mitotic spindle fibers)
Nucleus
Stores genetic information (DNA)
Rough Endoplasmic Reticulum
Facilitates the translation of secreted proteins or membrane proteins
Smooth Endoplasmic Reticulum
Synthesizes lipids, detoxifies molecules and acts as a Ca2+ storage
Free Ribosomes
Synthesizes proteins that are NOT excreted (used within the cell)
Golgi Apparatus
Packs and sends out proteins for transport, either outside the cell through exocytosis or to another organelle in a vesicle
Lysosomes
membrane bound sacks that contain hydrolytic enzymes that are used to break down organelle waste or proteins
Mitochondria
Converts glucose to ATP
Chloroplast
Converts photon energy to glucose
Plasma Membrane
Selectively permeable membrane that covers cells
lipid bilateral that allows nonpolar molecules to pass but not polar molecules without transport proteins.
Structure -> Function
Changes in structure may lead to changes in function because the specific shapes of organelles allow them to complete their tasks more efficiently.
Ex: Mitochondria cristae are folded in a way that gives it more surface area to perform cellular respiration
How is overall cell function dependent on organelles
Organelles and their individual membranes allow them to compartmentalize reactions therefore allowing multiple different reactions to take place at once, allowing for the efficiency necessary to maintain life.
How do prokaryotic cells divide?
Binary Fission:
Prokaryotic cell duplicates their DNA
FTsz proteins form a ring in the middle of the cell
plasma membrane and cel wall materials begin to form in the middle
once cell wall is present the cell splits into two
Eukaryotic Cell Cycle (Phases and Descriptions)
Interphase
G1 - growth phase
S phase - synthesis phase: DNA replicates
G2 phase - growth phase Mitotis
Prophase: Nuclear membrane dissolves, DNA begins to compress and mitotic spindle begins to form
Metaphase: Duplicated chromosomes are pushed to the metaphase plate by mitotic spindle fibers. 1 duplicated chromosome is just 1 sister chromatids
Anaphase: Mitotic Spindle fibers pull chromatids apart
Telophase: Chromosomes begin to lengthen and the cleavage furrow forms Cytokinesis
Cell splits into two and nuclear membrane reforms
Meiosis 1
Homologous chromosomes separate -> duplicated chromosome from mom and dad make up one homologous chromosome (4 chromatids) -> crossing over between non sister chromatids -> goes from 2n to n Independent Assortment of chromosomes along the metaphase plate
Peroxisomes
Detoxify substances like alchohols
Vacuoles
Fluid-Filled Sacs that can store water, food, salts, or pigments
Why are organelles evolutionarily advantageous?
Organelles allow for compartmentalization which allows for multiple reactions to occur at the same time. This ability is evolutionarily advantageous because it increases cellular efficiency.
Meiosis II
Prophase II consists of haploid cells that have sister chromatids Metaphase II consists of the sister chromatids lining up on the metaphase II plate Anaphase II consists of the sister chromatids separating from each other.
This is also where Mendels Law of Segregation is observed Telophase II and Cytokinesis Haploid cell splits into two haploid cells
What are the three factors that result in genetic variation
Crossing over at the end of prophase I, Independent Assortment during Metaphase I, and Random Fertilization
Honorable Mention = Anaphase II
Why is genetic variation among offspring an evolutionary advantage
Genetic Variation among offspring gives a higher chance for organisms of the population to survive if environmental conditions change. Therefore, it is evolutionarily advantageous to have offspring that vary genetically so that there is a higher chance the population survives
What are the 3 different life cycle types among sexually reproducing organisms?
Haplontic - Multicellular Haploid Stage is the most prominent and the diploid stage is the zygote which undergoes meiosis to form the haploid organism.
Diplontic - Multicellular Diploid Stage is the dominant life stage and haploid stage is present only in gametes formed by meiosis.
Haplodiplontic(Alternation of Generations) - Includes both dominant generations of diploid organisms (sporophytes) and haploid organisms (germatophyte)
What is the Genotype ratio of a monohybrid cross between 2 true-breeding individuals (one dominant and the other recessive)
100% Aa
True Breeding
An organism that is homozygous for an allele
What is the phenotypic and genotypic ratio of a monohybrid cross
Genotypic ratio: 1:2:1 Phenotypic ratio: 3:1
Genotype
The genes that underlie a physical trait
Phenotype
The expression of genotype
Mendels Law of Dominance
One allele is dominant over the other and will phenotypically mask its presence.
Mendels Law of Segregation
Alleles segregate into different gametes in Anaphase II of Meiosis II
Mendels law of Independent Assortment
Genes are separated into different gametes independent of one another
The orientation of homologous chromosomes around the metaphase I plate is independent of other homologous chromosomes.
What are the two other important dominance patterns and their definitions?
Co-dominance
Both alleles are dominant and are expressed
Ex: If the blue and red alleles for a color gene are codominant, the flower will have spots of red AND blue all over it
Incomplete Dominance
Neither allele is completely dominant, instead a blend of the two alleles are expressed
White allele and red allele are incompletely dominant and produce a pink flowered phenotype for heterozygotes.
What is the most common misconception of evolution and why is it wrong?
The most common misconception is that evolution happens because populations want it to happen, or that its strictly helpful.
This is wrong because evolution is completely due to random chance and it may even be harmful to a population. Evolution is based on the genetic variation in a population and therefore is not an intentional adaptation but an adaptation by chance.
What conditions must a population meet in order for it to evolve by natural selection?
The population must have: genetic variation, inheritable traits, and must live in an environment that cannot support the population.
What are the 5 different types of natural selection and describe them
Stabilizing Selection: Natural selection in which the neutral phenotype is selected for.
Directional Selection: One end of a spectrum of phenotypes are selected for (ex: animals on the white side of a black and white fur spectrum are selected for)
Disruptive Selection: Selection of the extremes of a phenotypic spectrum
Sexual Selection: Selection based on sexual fitness and preference for certain characteristics
Frequency-Dependent Selection: Selection based on the frequency of a phenotype
Positive: The more frequent a phenotype is, the more fit it is.
Negative: The less frequent a phenotype is, the more fit it is.
What are the 5 driving factors of evolution and describe
Genetic Drift: The random change in allele frequencies in a population over time Gene Flow: The transfer of genes from one population to another Mutation: Random mutations cause a populations allele frequencies to change Non-Random Mating: Non-Random mating indicates some preference for certain characteristics in a population -> therefore leading to sexual selection Natural Selection: Natural Selection is the selection of individuals based on the fitness of their phenotypes for the given environment.
What are the 2 different types of Genetic Drift and describe
Bottleneck Effect: When a random chance event kills off most of the population leaving a population of members that are not representative of the original population.
Founder Effect: When a small group, not representative of the original population, separates from the original population and settles in a new habitat. The allele frequencies here are different from the original which will lead to evolution.
What 5 conditions must be met for a population to be in Hardy-Weinberg Equilibrium
No Genetic Drift -> Large Population No Gene Flow -> Isolated Population No Random Mutations No Natural Selection Random Mating
What is Hardy-Weinberg Equilibrium
A state of a population in which it does not evolve and its allele frequencies do not change.
What are the Hardy Weinberg equations?
p + q = 1 p = frequency of dominant allele q = frequency of recessive allele
p^2+2pq +q^2 = 1 p^2 = frequency of homozygous dominant genotype 2pq = frequency of heterozygotes q^2 = frequency of homozygous recessive genotype
Genotype Frequency
Frequency of a certain genotype (specific gene composition) in a population
Heterozygous genotypes are a separate frequency
Phenotype Frequency
Frequency of phenotypes in a population
Heterozygotes are counted as part of the dominant phenotype frequency if the gene displays complete dominance.
What is an example of natural selection
Development of antibiotic resistance
What are the two types of speciation
Allopatric Speciation and Sympatric Speciation
Allopatric speciation is speciation that occurs due to the geographical separation of a population of the certain species. Once separated, the two groups may develop distinct traits and evolve into new species.
Sympatric Speciation is speciation that occurs in the same geographical area. Can occur due to conditions that make members of the same species unable to mate. -> Sexual Selection can cause this. Also nutrient separation in the same habitat can cause this.
What are the Prezygotic Barriers and explain them
Prezygotic Barriers are barriers that inhibit 2 species from mating in the first place.
Habitat Isolation: 2 species are separated geographically and therefore cannot mate
Gametic Isolation: The gametes of one species may not be recognized for fertilization
Mechanical Isolation: The location of reproductive organs on the 2 species make them unable to physically mate.
Temporal Isolation: The times of ovulation or fertility of the 2 species do not line up.
Behavioral Isolation: When a species does not respond to mating behaviors of other species.
What are the Post zygotic Barriers and explain them
Postzygotic barriers prevent a population of hybrid individuals from forming.
Reduced Hybrid viability: Hybrid individuals die before birth
Hybrid Sterility: Hybrids are sterile and cannot reproduce
Hybrid Breakdown: While the first generation hybrids can breed with individuals of either parent species, the second generation hybrids are sterile.
How do the reproductive isolating mechanisms( pre and post zygotic barriers) support speciation.
A species by definition consists of individuals that cannot breed with other species, therefore, the reproductive isolating mechanisms ensure that a new species is formed by inhibiting mating with other species.
List the hierarchy of taxonomy from largest to smallest
Does King Phillip Come Over For Good Spaghetti Domain Kingdom Phylum Class Order Family Genus Species
Binomial Nomenclature
Way of naming species (Name of Genus) (Name of species)
Ex: Polar Bears and Brown Bears are part of the same genus
Polar bears: Ursus Maritimus
Brown bears: Ursus Arctos
What are the main adaptations that plants developed for land, and how did each help?
Alternation of Generations
Allowed plants to alternate between a sexually producing generation and an asexually reproducing generation in the case of harsh environments
Vasculature
Allows plants to grow larger while still being able to effectively transport water and nutrients throughout their body.
Apical Meristems
Allows plants to grow in their shoots and roots to access more resources-> growing towards the sun to access more light energy and growing in the soil to access more nutrient rich soil
Cuticle
Prevents desiccation (water loss) which is extremely important for plants.
What are the 4 main groups of land plants?
Bryophytes Seedless Vascular Plants Gymnosperms Angiosperms
Bryophytes
Nonvascular plants
Seedless
Gametophyte Dominant Life Cycle in which sporophyte grows and develops on the gametophyte completely.
GAMETES released, not spores
Consists of Mosses primarily
Can be heterosporous or homosporous
Seedless Tracheophytes
Seedless Vascular Plants
Sporophyte dominant Life Cycle in which the gametophyte is completely INDEPENDENT of the sporophyte
Spores are released
Gametophyte can grow independently of the sporophyte since the spore that is released from the sporophyte develops into the gametophyte.
Can be heterosporous or homosporous
heterosporous
A term denoting that a plant produces 2 types of spores that develop into specific male or female gamtophytes
BASICALLY: a plant that produces male or female spores.
Male spores are called Microspores Female spores are called Megaspores
homosporous
A term denoting that a plant produces only one type of spore which develops into a hermaphrodite gametophyte, a gametophyte that has both male and female gametangia.
Sporangia
Structure in a a sporophyte in which the spores are developed
Megasporangia
Produce megaspores that develop into female gametophytes
Microsporangia
Produce microspores that develop into male gametophytes
Gametangia
Structure on a gametophyte in which gametes are produced, male or female.
Male gametangia -> Antheridia Female gametangia -> Archegonium
Spermatophytes
Seed Vascular Plants
Consist of Angiosperms and Gymnosperms
Sporophyte dominant generation with dependent and reduced gametophyte
Male gametophyte = pollen
Seed = Zygote formed by fertilization of female gamete.
Seeds are released as well as male gametophytes in the form of pollen ALL are heterosporous
What are the 3 main types of plant cells
Parenchyma
Thin walled plant cells
Most common in plants Collenchyma
Thick but FLEXIBLE cell walls Sclerenchyma
Extremely thick RIGID cell walls packed with lignin that provide structure to plant
Found dead at maturity
How do Monocots and Dicots differ in terms of roots, stems, and leaves
Roots:
Monocots have fibrous dense roots
Vascular structures are arranged in a ring around the pith
Dicots have a tap root system
Vascular structures are arranged in an alternating X pattern in the sclera
Stems:
Monocots have the vascular bundles randomly scattered throughout the stem
Dicots have their vascular bundles arranged in a ring formation around the central pith in the stem
Leaves:
Monocots have linear venation in their leaves
Dicots have highly branched venation in their leaves
What are the 3 types of permanent tissues in plants
Vascular Tissue
Xylem and Phloem Ground Tissue
Parenchyma, Sclerenchyma, and Collenchyma Cells
Cells that conduct photosynthesis, store materials, etc.
Basically cells that aren't part of the xylem, phloem, or any of the dermal linings. Dermal Tissue
dermal linings of the plant structures and internal linings.
An area where leaves diverge off of a stem is called what?
A node
What are the 2 types of tissues in plants?
Meristematic Tissue and Permanent Tissue
What are the 3 types of Meristematic Tissues?
Apical Meristematic Tissue
Found in root tips and shoot tips and allow the plant to grow up and down.
Lateral Meristematic Tissue
Found in the stems or shoots of plants/woody trees that allow them to grow outwards/ become thicker.
Intercalary Meristematic Tissue
Only found in Monocots and allows them to grow their leaves longer after they are cut (ex: grass)
What is the difference between Pollination and Fertilization?
Pollination is when the male gametophyte (pollen) lands on the stigma of a flower and builds the pollen tube to the female ovules.
Basically the event of pollen traveling to another flower
Fertilization is the actual act of the male gametophyte producing 2 sperm cells that travel down the pollen tube and fertilize the eggs.
What are the main organ systems of plants?
Leaves, Stems and Roots
The area in a root where cells begin to differentiate into permanent tissue is called what?
Region of maturation
What are the 3 main tropisms of plants?
Phototropism, Gravitropism, and Thigmotropism
What are the characteristics of Bryophytes?
non-vascular, seedless, flagellated sperm, requires water to reproduce, Gametophyte dominant
Moss
What are the characteristics of seedless tracheophytes
Seedless, have vasculature, release spores, sporophyte dominant with gametophyte INDEPENDENT, requires water to reproduce.
Ferns
What are the characteristics of Gymnosperms
naked seeds that are not protected by ovary(fruit)
Have vasculature, seeds, release seeds, sporophyte dominant with dependent and reduced gametophyte
Also release pollen (male gametophytes)
A seed is a mature _________
Ovule
The individual casings for the eggs inside the ovary
A fruit is a mature ______
Ovary
Structure that contains all of the ovules in a flower.
What are the characteristics of angiosperms?
Flowering plants with seeds (ovules) that are encased by fruit (ovaries)
Have vasculature, seeds, sporophyte dominant with reduced dependent gametophyte
Describe the Life Cycle of angiosperms
The sporophyte (heterosporous) produces a male and female spore. The male spore is housed in the anther of the sporangia where it develops into a gametophyte before it is released.
The gametophyte is composed of 2 cells, a pollen tube cell and a cell that becomes the 2 sperms during fertilization.
When the male gametophyte (pollen) is transferred (by water, wind, animals, explosions, etc.) onto the stigma of a flower, the pollen tube cell starts developing into the pollen tube reaching down the stigma through the style and attaching to an ovule in the ovary.
This is pollination
Inside the ovule, the female spores are produced which then develop into female gametophytes. Each gametophyte produces 4 gametes but only 1 survives which's consists of an egg cell and a polar nuclei body and 6 other cells.
When the sperm reach the ovule, one sperm fertilizes the egg and the other fertilized the polar nuclear body developing into an endosperm that acts as a source of nutrition later on for the seed. -> Fertilization
The zygote then develops into a seed in the ovary and when fully mature, the ovary develops into a fruit to protect the seed and acts as a vehicle for transportation for the seed.
How are fruits vehicles of transportation
Fruits can be carried by wind, animals, water, etc.
What is sporopollenin and why is it considered an evolutionary advantage
Sporopollenin is a material found in he casings of shells and pollen that is unnaturally resistant to chemical and biological changes, allowing seeds and pollen to survive HARSH conditions and still pollinate or germinate.
What is phototropism and how does it work?
Phototropism is the tendency for plants to grow in response to light
When sunlight hits a plant in an angle, the auxins in the plant move to the shaded side of the plant. When there are a lot of auxins on one side of a plant, they promote cell elongation, and therefore promote cell elongation on the shaded side of the plant. This causes the plant to grow tawdry the light since the side facing the light is not elongating.
What is gravitropism and how does it work?
Plastids in the plant cell called amyloplasts react to gravity. When a plant is growing slanted, the amyloplasts settle in the bottom corner of the plant and induce cell elongation. Therefore the cells on the bottom portion of the slanted plant elongate faster therefore making the plant grow upright!
What is thigmotropism and how does it work?
When the stem makes contact with an object, the cells that make contact with the object slow their growth/elongation, making the stem wrap around the object.
Body Plans
Bilateral Symmetry Radial Symmetry Asymmetrical
What shape do aquatic animals usually have an why?
Fusiform Shape The Fusiform shape allows aquatic organisms to limit drag on their body's from water.
What governs land animals adaptations?
Gravity
What is an exoskeleton
Hard outer covering (shell) that provides protection to organs, allows the attachment of muscles and only in land animals, prevents desiccation
What is the main limitation of an exoskeleton
Exoskeletons cannot grow with the organism and as such they need to be molted then replaced in order for animals to grow
Endotherm
An animal that maintains an internal body temperature through metabolic activity,
Exotherm
Animals that regulate their body temperatures by exchanging heat with their environment
What are the 4 types of animal tissues
Epithelial, Connective, Muscle, Nervous
What are the different cells that make up epithelial tissue
Squamous epithelial cells: Flat, thin, round cells
Can be in a single thin layer (facilitate diffusion) or stratified (protect body from damage)
Cuboidal epithelial cells: uCbe shaped cells
Secrtete glandular materials (often found in gland tissues)
Columnar epithelial cells
Tall cells that are almost always in a single cell arrangement
Transitional Epithelial Cells
Found in the bladder
Stratified and stack on top of each other but can TRANSITION to be very thin layers in order to expand the volume of the bladder
What are the different Tissues are part of Connective Tissue
Adipose, Blood, Fibrous, Areolar, Bone, Cartilage Tissue
Adipose Tissue
Fat Tissue Found in Subcutaneous fat tissue Cells: Adipocytes (stores fat)
Blood Tissue
Liquid extracellular matrix: plasma
Found in...blood Cells: erthythrocytes (RBC) and leukocytes(WBC)
Fibrous Tissue
Tissue that binds structures together
Found in the dermis, TENDONS and Ligaments
Cells: Fibroblasts and Macrophages
Fibers: Mostly Collagen
Loose/ Areolar Tissue
Binds skin together and to underlying organs and keeps organs in place
Found in the dermis
Most widespread
Cells: Fibroblasts, Macrophages, neutrophils, and some lymphocytes
Fibers: A little bit of all 3
Bone Tissue
Most rigid connective tissue, Internally supports body structures
Found in the Skeleton
Cells: Osteoblasts (make other osteo- cells), Osteocytes (regulate calcium deposition), and Osteoclasts (recycle osteocytes and bone tissue to make room for new bone- very active in bone repair)
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