Living Environment Summary Notes

Cells

• Sequence of Structural Organization

  • Organelles → Cells → Tissues → Organs → Organ System (smallest/simplest to largest/complex).

• Unicellular Organisms

  • Single-celled, simple organisms.

  • Perform life processes without organ systems.

  • Example: Protozoan (paramecium).

• Multicellular Organisms

  • Complex organisms composed of many cells.

  • Perform life processes with organ systems.

• Homeostasis

  • Maintaining internal stability.

  • Involves nervous and endocrine systems.

Characteristics of Living Things

• Factors required to be considered a living thing:

  • Perform metabolic processes.

  • Maintain homeostasis.

  • Need energy for cell activities.

  • Composed of one or more cells.

Cell Structure

• Cell Organelle = Cell Part

Organelles and Their Homeostatic Functions

• Nucleus

  • Controls most cell activities.

  • Contains DNA (hereditary factors).

• Mitochondria

  • Site of aerobic cellular respiration (energy release).

• Chloroplast

  • Site of photosynthesis (autotrophic nutrition; found in plant cells).

• Cell Membrane

  • Selectively regulates the passage of materials into and out of the cell.

• Ribosomes

  • Site of protein synthesis (enzyme).

• Vacuole

  • Storage of waste, food, excess water.

Life Processes

• Life Process = cell metabolic/physiological activities = chemical reactions = cell processes.

Homeostatic Functions of Life Processes

Regulation

• Control and coordination of physiological activities.

Synthesis

• Forming complex molecules from simple molecules.

  • Example:

    • Photosynthesis: $CO<em>2 + H</em>2O \rightarrow C<em>6H</em>{12}O<em>6 + O</em>2 + H_2O$

    • Protein synthesis: amino acid + amino acid + amino acid → polypeptide (protein).

Respiration

• Release of stored energy from an organic molecule (glucose).

• Transfer of chemical energy to a more usable form (ATP).

Transport

• Movement of molecules into or out of the cell.

  • Passive transport (diffusion, osmosis).

  • Active transport.

Nutrition

• Autotrophic: Organisms produce their own food, e.g., plants.

• Heterotrophic: Organisms must obtain and ingest preformed organic molecules.

Digestion

• Breakdown of food into nutrients.

Excretion

• Removal of metabolic waste.

Comparison of Body Systems, Cell Organelles, and Life Processes

Interaction of Body Systems

• Example 1: Nucleus (DNA code) produces proteins via ribosomes.

• Example 2: Cell membrane allows glucose passage; mitochondria use it for cell respiration.

Body Systems and Their Functions/Disorders

Digestive System

• Organs: Stomach, small intestine, large intestine

• Functions: Breaks down food, reabsorption of water

• Disorder: Ulcer

• Note: Large organic molecules (starch, protein, lipid) are digested into small organic molecules (glucose, amino acid, fatty acid) which are end products of digestion and easily absorbed into blood vessels.

Respiratory System

• Organs: Nose, lungs, alveoli, bronchioles

• Functions: Filters air, exchange of gases in lungs and alveoli

• Disorders: Asthma, emphysema, bronchitis

• Note: $O<em>2$ diffuses from alveoli into blood vessels; $CO</em>2$ diffuses from blood vessels into alveoli.

Circulatory System

• Organs: Heart, veins, arteries

• Functions: Pumps blood, carries blood

• Disorders: Heart attack, leukemia

Excretory System

• Organs: Skin, kidneys, liver, lungs

• Functions: Removes wastes, regulates temperature, removes dead red blood cells, removes $CO_2$

• Disorder: Kidney stones

Nervous System

• Organs: Brain, nerve

• Functions: Regulates body activities, cell communication

• Disorders: Alzheimer's, polio

Endocrine System

• Organs: Glands

• Functions: Produces hormones, cell communication

• Disorder: Diabetes

Immune System

• Cells: White blood cells (WBC)

• Functions: Produce antibodies, engulf pathogens, attack/kill pathogens

• Disorders: AIDS, allergies

Biochemistry

Enzymes

• Organic catalysts that speed up the rate of reactions.

• End with "-ase".

• Composed of amino acids.

• Control specific chemical reactions (enzymatic activities).

• Have a specific shape that binds with their substrate.

Factors Influencing Enzyme Reaction Rate

• Optimum Temperature: $37°C$

  • High temperature: enzyme reaction slows down, denatures enzymes.

• pH: Each enzyme functions at an optimum pH.

• Amount of Substrate/Enzyme

Examples of Enzymes and Substrates

Organic Compounds

• Contain carbon and hydrogen bonds.

Types of Organic Compounds

Chemical Processes

• Hydrolysis: Chemical process that breaks down complex substrates (e.g., digestion).

• Dehydration Synthesis: Chemical process that synthesizes simple materials into complex ones (e.g., protein synthesis, photosynthesis).

Energy Transformation Processes

Photosynthesis and Respiration

Notes

• Most autotrophic nutrition (photosynthesis) occurs in palisade layers of a leaf.

• Guard cells help plants maintain homeostasis by regulating gas exchange and water loss.

Autotrophic Nutrition - Photosynthesis

• Light energy is converted into chemical energy.

• Inorganic materials ($CO<em>2$, $H</em>2O$) are used to produce an organic material (glucose).

• Dehydration synthesis process.

• Occurs in the chloroplasts of autotrophs.

• Wavelength of light: red/blue - highly absorbed - effective in photosynthesis.

Factors Influencing Rate of Photosynthesis

• Amount of water: More $H_2O$, faster photosynthesis.

• Light intensity.

• Amount of $CO_2$

• Mineral presence.

Aerobic Cellular Respiration

• Glucose is oxidized to release a more usable form of energy.

• Releases stored energy (ATP) for cell activities.

• Hydrolysis process controlled by respiratory enzymes.

• Requires oxygen to completely breakdown glucose to produce ATP.

• Potential energy in glucose is transferred to ATP.

• Occurs in mitochondria of cells (e.g., muscle cells have many mitochondria).

• ATP = adenosine triphosphate

Transport

• Absorption of materials into the cell and distribution of materials within the cell.

Cell Membrane (Plasma Membrane)

• "Semipermeable" or "selectively permeable".

• Composed of proteins and lipids.

• Selectively controls passage of materials into and out of cells.

• Receptor proteins in cell membrane attach to specific molecules (hormones, neurotransmitters).

Materials that Can Diffuse Easily Into/Out of a Cell

• Glucose, food particles (diffused from small intestines).

• Oxygen (diffused from lung cells to blood cells, from blood cells to muscle cells).

• Carbon dioxide (diffused from blood cells to lung cells, from muscle cells to blood cells).

Active Transport

• Needs ATP for passage of materials.

• Large soluble or insoluble molecules like proteins, starch, fats.

• Movement of materials from a low concentration to a high concentration.

Passive Transport

• No energy is needed for passage of materials.

• Small molecules like glucose, water, dyes.

• Movement of materials from a high concentration area to a lower area.

• Diffusion = passive transport.

Osmosis

• Movement of WATER from a high concentration area to a lower area.

• Add salt: Water diffuses out of the cell - cell volume decreases (cell membrane and cytoplasm shrinks). No change in cell wall.

• Add distilled water: Water diffuses into the cell - cell volume increases (cell membrane and cytoplasm expands). No change in cell wall.

Genetics

Nucleic Acids

• Organic compound: DNA and RNA.

• Basic unit: nucleotide (phosphate group, sugar group, nitrogenous base).

• Nitrogenous base (A, T, C, G).

• DNA base sequence → RNA base sequence → amino acid sequence → shape of protein → protein function in cell.

Organization of Genetic Material (largest to smallest)

• Nucleus contains DNA (deoxyribonucleic acid) - genetic code to make PROTEINS.

• Gene - a segment of DNA

• DNA = known as a Polynucleotide - composed of many nucleotide

• Ribosomes is the location where proteins are assembled (made/produce/manufacture).

• Gene-chromosome theory: genes are located in a linear sequence on a chromosome.

• Each chromosome holds hundreds of genes.

Chromosomes

• Homologous Chromosomes = double strand

DNA Structure and Replication

• Watson and Crick discovered the structure of DNA - double helix.

• Complementary base pairing held together by weak hydrogen bonds.

• DNA Replication - copy of DNA strand.

  • Occurs prior to cell division - mitosis and meiosis.

  • New strands formed using DNA template as a pattern.

  • DNA unzips at weak hydrogen bonds.

RNA

• Ribonucleic Acid = Single strand polynucleotide

Types of RNA

mRNA (messenger RNA)

• Copies code from DNA strand in the nucleus -- Transcription

• mRNA leaves the nucleus and goes to the Ribosome carrying the code to make proteins

tRNA (transfer RNA)

• Carries the specific amino acid to the ribosomes :occurs in Translation

• Amino acid sequence determines Shape of Protein determines

Codon

• Codes for an amino acid. Composed of 3 nucleotide (molecular bases)

• Examples of codons # of codons = 2 DNA codons TAT CGG RNA codons ADA GeC

Genetic Code

Genetic Disorders

Mutation

• A change in the DNA

• Normal Base Sequence ATT CGG ATT CGG ATT CGG

• Mutagenic Factor X-rays radiation UV ray

Gene Mutation

• Only One base nucleotide is changed

• Mutagenic factor = mutagens = factors in the environment that causes mutation (ie. X-Rays, chemicals…)

• Examples:

  • ATT CGA substitution

  • ATT CG deletion

  • ATTCGGG addition

Inheritance and Chromosomes

• Organisms that reproduce sexually inherit half of their DNA from each parent.

Sex Determination

• Sperm unites/fertilizes the egg resulting in

  • Normal male with 46 chromosomes

    • Sex of a child determine by male.
      22 autosome + Y
      22 autosome + X
      44 autosome + XY (sex chromosomes) XY

  • Normal female with 46 chromosomes
    22 autosomes + X
    22 autosomes + X
    44 autosomes + XX (sex chromosomes) XX

Karyotype

• Normal Male Karyotype: map or photograph of chromosomes

• Arranged by size/pair of homologous chromosomes

• Detect genetic disorders - Down syndrome- extra set of chromosome( #21)

DNA Code Translation (Example)

• DNA code sequence TTT AGG ATA CCG

• RNA base sequence AAA UCC UAU GGC

• Amino acid sequence Lys - Ser - Tyr - Gly

Mutation Consequences

• Can be neutral or harmful

• Example: change in amino acid sequence (UCC → UCU) may or may not alter protein function

• Mutation in a gene can be inherited if mutation occurs in the sex cells.

Techniques to Alter DNA

Gene Expression

• Environmental factors (light, temperature, environment) can influence the expression of certain genes.

Cell Differentiation

*Explain how two different types of cells containing the same genetic instruction can function differently in an organism.
*Possible Responses:
* Different segment of the DNA code is express by different cell environment.
* Cell differentiation occurred.
* Each type of cell expresses different genes
* Each cell produces a specific protein
* Different cells contain different proteins

Reproduction

• Life process: a. produces new cells or organism b. repairing of tissues

Types of Reproduction

Asexual

• Parents: one

• Cell division: mitosis

• DNA content in the offspring: same DNA as parent

• Variation: no variation

• Organisms: ameba, yeast,hydra, potato, apple,

Sexual

• Parents: two

• Cell division: meiosis

• DNA content in the offspring: ~ DNA from each parent

• Variation: has variation

• Organisms: human, animals

Types of Asexual Reproduction

Binary Fission

• equal division of nuclear material and cytoplasm

• example organisms - protest such as ameba, paramecium, euglena

Budding

• equal division of nuclear material and unequal cytoplasm division

• example organisms - yeast cells, hydra

Sporulation

• release of spores.

• ex. mushroom or bread mold

Regeneration

• producing an organism from each halve of parent cell. Re-growth of missing body palis due to undifferentiated cells.

• Ex. starfish, planaria ,lobster

Vegetative Propagation

• new plants formed from roots, leaf, or stems. Grafting

Mitotic Cell Division

• Process of forming two identical daughter cells from a single parent cell: Offsprings (daughter cells) genetically identical to parent cell. Inherited same DNA as parent cell.

• Asexual Reproduction is the reproductive method. Associated with Cloning method

• In multicellular organisms - produces Diploid Cells (body cells)

• Cell Cycle: cell begins to divide

1. in unicellular cell DNA is copied $2N =2N$

2. in a plant cell

3. Telophase in an animal cell

Cancer: uncontrollable cell division

Sexual Reproduction

• Two parent cells form an offspring that is genetically different from them.

• Each parent cell contributes ~ of DNA to offspring. Provides Genetic Variation.

• Involves Meiosis Cell Division
  Involves Meiosis Cell Division

• one haploid cell (egg) meiosis in Females ovaries (reproductive, sex cells) (1 haploid cell). Contributes to Genetic Variation

• four haploid cells meiosis in Males testes = (reproductive, sex cells) sperm (4 haploid cells)

• Meiosis Cell division, Occurs in sex organ /glands = Gonads: male testis female ovary

• Separation of homologous chromosomes results in monoploid (haploid) cells.

• Produces males gametes = Sperms (reproductive, sex cells) 4 haploid cells

• Produces females gametes = Ovaries (reproductive, sex cells) 1 haploid cell Contributes to Genetic Variation

Chromosome Number

• Diploid number (2n): total number of chromosome in a species. Human is 46 chromosomes (body cells)

• Monoploid number (n):one-half of the total number of chromosomes in a species. 23 chromosomes (sex cells

Fertilization

• Process that restores the diploid Number of Chromosomes, in which the sperm and the egg unite to form a zygote

Genetic Content Comparison

• Sperm - has 23 chromosome / carries ~ of parent 's DNA / a monoploid cell

• Egg - has 23 chromosomes / ~ of parent's DNA / a monoploid cell

• Zygote - has 46 chromosomes / diploid cell

• Body cells of parent - has 46 chromosomes / diploid cells

• Body cells of developing embryo - has 46 chromosomes / diploid cells

Types of Development

• Embryo Development Cleavage ---- gastrulation ---- differentiation meio sis zygote 3 embryo developmental process

Human Reproduction

Female Reproductive Tract

*Ovary:
paired gonads, reproductive organ

• Ovary:
  Process- site of meiosis (egg production- gamete production, egg maturation)
  Process- hormone production - estrogen / progesterone
  *Oviduct: paired organs

• Oviduct:
  Process- site of internal fertilization
  Process- site of cleavage (mitosis)

• Uterus: thin sac, placenta formed

• Uterus:
  Uterus lining thickens by estrogen & progesterone -during menstrual cycle
  Process- site of internal development (fetal/embryo)

Male Reproductive Tract

*Testes: paired gonads, reproductive organs
Process: site of meiosis (sperm production - gamete production)
Process: hormone production - Testosterone

• Scrotum: sac, provides optimum temperature 2-3 degrees below body temperature

• Penis: adaptive structure for internal fertilization

Fetal Development

• Placenta: structure that is formed in the uterus form from maternal tissues I fetal tissues

• Functions of placenta: provides Nutrition( obtains nutrients), Respiration (exchange of gases) and Excretion (gets rid of waste from fetus)
  *Umblical Cord: serves as an attachment from fetus to placental tissues

Factors Affecting Fetal Development

Twins

• Fraternal twins - 2 eggs fertilized by 2 different sperm (Non-Identical or fraternal twins result from two separately fertilized eggs, so they are no more genetically similar than non-twin siblings.)
  *

• Identical twins - 1 egg fertilized by 1 sperm with a genetic similarty, although some studies have suggested that the DNA in identical twins is not exactly the same because of environmental factor can have an affect.

Cell Division Comparison

Menstrual Cycle

• Menstrual Cycle Control by hormones, hypothalamus, and pituitary gland
  Phases at the Menstrual Cycle

• production of progesterone by tissue in a follicle
  1 folllide Stage Event Maturation of the egg and secre tion of estrogen. hormones: FSH Estrogen
  2 ovulation Stage Event Release of the egg. hormones: LH Progesterone
  3 l~lic Stage Event Shedding of tlie thidc.- enad uterine lining Hormones:
  *Negative feedback example:
  High level of FSH cause increase of Estrogen
  High level of Estrogen lowers FSH level

*Hormones FSH: regulates egg maturation, LH: regulates ovulation (egg released from ovary), Estrogen: released from ovary, thickens uterus lining , Progesterone: released from ovary, thickens uterus lining

Evolution

Evolution: change in species over time. Existing life forms have evolved from earlier life forms.