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Biology Review Flashcards

1
Q

How are sister chromatids held together?

A

at a central region called the centromere

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2
Q

What type of cell does Mitosis divide?

A

somatic cells

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3
Q

what is it called when the nuclear division occurs?

A

karyokinesis

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4
Q

what is it called when the cell divides?

A

cytokinesis

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5
Q

How does the plant cell divide vs. animal cell?

A

Animal = cytokinesis

Plant = cell plate formation

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6
Q

What occurs in ANIMAL prophase?

A

The chromosomes condense and the CENTRIOLE PAIRS SEPARATE and move toward opposite poles of the cell

Spinld apparatus forms between them and the nuclear membrane dissolves, allowsin the spindle fibers to interact with chromosomes

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7
Q

When do the spindle apparatus attach to each chromatid?

what is the location of this attachment point?

A

metaphase = metaphase plate formation stage

kinetochore

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8
Q

When does the centromere split so that each chromatid has its own distinct centromere?

A

anaphase

spindle fibers (microtubules) pull sister chromatids to opposite ends as they shorten

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9
Q

When does the nuclear membrane reform?

Haploid or diploid?

A

Telophase

diploid (2N) as the original or parent nucleus

chromosomes uncoil and resume their interphase form

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10
Q

How does sexual reproduction differe from asexual reproduction?

A

two parents involved

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11
Q

What is the result of a (2N) diploid cell in Meiosis division?

A

four haploid cells called gametes

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12
Q

When does cross over occur?

A

Prophase I

between the tetrads = homologus chromosomes

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13
Q

What is the point of contact between the homologous chromosomes where crossing over can occur called?

A

chiasmata

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14
Q

When does disjunction occur?

A

Meiosis

Anaphase I

accounts for a fundamental Mendelian law - either chromosome can end up in either daughter cell

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15
Q

When does nondisjunction occur?

A

cells do not separate appropriately during meiosis

result = incoorect number of chromosomes

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16
Q

What are the six kingdoms?

A

bacteria, archaea, Fungi, Plantae, and Animalia

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17
Q

What is the cell membrane permeable to? what is it not permeable to?

A
  • Permeable to:
    • Small, nonpolar, hydrophobic molecules such as oxygen
    • small polar molecules, such as water
    • small charged particles can pass through using protein channels
  • Not permeable to:
    • Large charged molecules and charged ions cross membrane with help from carrier proteins
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18
Q

What is the smooth ER responsible for?

A

Metabolism and lipid production

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19
Q

How does transport within the cytoplasm occur?

A

cyclosis (streaming movement within the cell)

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20
Q

What is the difference between vesicles and vacuoles and where are they found?

A

Vacuoles are larger volume vesicles and are more likely to be found in plants than in animal cells

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21
Q

What are centrioles composed of and what are they responsible for?

A

microtubules

are involved in spindle organization during cell division

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22
Q

Animal cells have a pair of centrioles originated at a right angle to each other that lin in this region ___?___

A

centrosomes

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23
Q

Animals have this specific microtubule organelle and plant cells do not

A

centrioles

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24
Q

What are membrane - bound vesicles that contain hydrolytic enzymes involved in intracellular digestion?

A

Lysosomes

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25
Q

What is it called when an injured or dying cell self-destructs by rupturing the lysosome membrane

A

autolysis

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26
Q

What is the cytoskeleton function and what is it composed of? (describe each)

A
  • Function:
    • Supports the cell, maintains shape and aids in cell motility
  • Composed of:
    • Microtubules
      • Hollow rods made of polymerized tubulin
      • provide support, transport during cell division, cilia and flagella
    • Microfilaments
      • solid rods of actin
      • important for cell movement and support
    • Intermediate filaments
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27
Q

What is it called when the medium outside of the cell has less solute particles than inside the cell?

What will happen to the cell?

A

Medium is hypotonic to cell

cell will lyse (burst)

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28
Q

What is it called when the medium outside of the cell has more solute particles than inside the cell?

What will happen to the cell?

A

Medium is Hypertonic to cell

plasmolysis = cell will shrivel

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29
Q

Where does cellular respiration occur in prokariotes vs. eukaryotes?

A

Prokariotes = cell membrane

Eukaryotes = mitochondria

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30
Q

Explain the central dogma

A

DNA (Self-replication back to itself)

Transcription

RNA

Translation

Protein

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31
Q

What is a nucleotide?

A

deoxyribose (a sugar) bounded to both a phosphate group and a nitrogenous base

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32
Q

What are the purines and what do they look like?

A

Guanine (G) and Adenine (A)

Double ring

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33
Q

What are the pyrimidines and what do they look like?

A

Cytosine (C), Uracil (U) and Thymine (T)

One ring structure

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34
Q

What did Watson-Crick DNA model look like?

A

Antiparallel arrangement

A - T

C - G

Via hydrogen bonding

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35
Q

What is the function of topoisomerase and DNA helicase?

A

Unwinding and separate the two single strands and breaks the hydrogen bonds between the nitrogenous bases of eeach nucleotide

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36
Q

Explain semiconservative replication

A

each new daughter helix DNA strand contains an intact strand from the parent helix and a newly synthesized strand

** The daughter strand of DNA formed from the parent strands are identical to the parent strands

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37
Q

Which direction does the DNA polymerase read the DNA parent strand?

A

3’ -> 5’

synthesizing DNA 5’ -> 3’

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38
Q

How many different codons are possible and how many amino acids total?

A

64

but only 20 amino acids need to be coded

39
Q

With there being so many different codons that code for the same amino acid, what is this called or referred to as?

A

degeneracy or redundancy of the genetic code

40
Q

What does it mean for mRNA to be monocistronic?

A

meaning one mRNA strand codes for one polypeptide

41
Q

What type of molecule contains the anticodon?

A

tRNA

42
Q

Explain the steps of transcription

A
  • Transcription
    • = process through which information coded in the base sequence of DNA is used to direct the synthesis of a strand of mRNA
  • Steps
    1. RNA polymerase binds to the DNA at a promoter region, a short DNA sequence found upstream from the site where transcription of specific RNA will take place
      • Humans = TATA Box
    2. Transcription factors then help RNA polymerase bind to the DNA molecule and initiate transcription
    3. RNA polymerase surrounds the DNA molecule after it has been opened by the action of DNA helicase and topoisomerase
    4. RNA polymerase then recruits and adds complementary RNA nucleotides based on DNA sequence
      • Synthesizing 5’ -> 3’
      • Where RNA polymerase reads 3’ -> 5’
    5. After transcription is completed, mRNA undergoes post-transcriptional processing
      • RNA that has not yet peen prcessed = hetero-nuclear RNA (hnRNA) or pre-RNA, and contains extra nuceotides that are not necessary to create the corresponding protein (introns and removed by spliceosomes)
      • Guanine cap and Poly-A tail is added to the ends of the molecule to prevent degredation once RNA leaves the nucleus
43
Q

Explain the steps of transcription

A
  • Translation
    • = Process through which mRNA codons are translated into a sequence of amino acids
    • Occurs in cytoplasm and involves tRNA, ribosomes, mRNA, amino acids, enzymes and other proteins
    • Four steps: Initiation, elongation, translocation and termination
  1. Initiation
    • begins when the ribosome binds to the mRNA near 5’end
    • Scans to find start codon (AUG)
      • Anticodon = 3’-UAC-5’
  2. Elongation
    • Hydrogen bonds form between mRNA codon in the A site of the ribosome and complementary anticodon on the incoming tRNA
    • Peptide bond is formed between amino acids attached to the tRNA in A site and AA attached to tRNA in P site
  3. Translocation
    • ribosome advances three nucleotides along mRNA in the 5’ to 3’ direction and new tRNA enters
  4. Termination
    • When one of three special mRNA trermination codons, or stop codons (UAA, UAG, or UGA) arrive in the A site which signal to terminate and do not code for an AA
    • Frequently, numerous ribosomes simultaneously translate a single mRNA molecule, forming a structure known as a polyribosome
44
Q

Explain ribosome translation and the units that make up the ribosome

A
  • Ribosome:
    • Location of translation
    • Composed of two subunits, one small and one large consisting of proteins and rRNA
    • Make up three binding sites for tRNA:
      • A (aminoacyl complex), P (peptide bond form) and E site (exit)
45
Q

What is assimilation?

A

The building up of new tissues from digested food materials

46
Q

Explain two major types of regulation

A
  • Regulation = The control of physiological activities. The body’s metabolism functions to maintain its internal environment in a changing external environment
    • Homeostasis = regulation by hormones and the nervous systerm
    • Irritability - the ability to respond to a stimulus and is part of regulation
47
Q

Explain the difference between external respiration and internal respiration

A
  • External respiration = entrance of air into the lungs and the gas exchange between the alveoli and the blood
  • Internal respiration = exchange of gas between the blood and the cells and the intracellular processes of respiration
48
Q

What are the fuel molecules in living cells?

A

carbohydrates and fats

49
Q

Explain the basic repiration reaction

A
  • High energy hydrogen atoms are removed from organic molecules
    • = dehydrogenation and is an oxidative reaction
  • Subsequent acceptance of hydrogen by a hydrogen acceptor (oxygen is the final step) is a reduction component of the redox reaction
50
Q

Explain the catabolism of glucose

A

Degrative oxidation of glucose occurs in two stages:

  1. Glycolysis = 2 pyruvate produced (energy payoff and energy production stage)
  2. Cellular respiration = 34 ATP produced
  • TOTAL ATP PRODUCTION = 36 ATP
51
Q

What is the Aerobic Glycolysis pathway?

A

With oxygen

  1. Glucose
  2. Glycolysis -> 2 pyruvate + 2 ATP + 2 NADH
    • = 8 ATP (2 substrate, 6 oxidative)
    • ​​Occurs in cytoplasm
  3. Decarboxylation of pyruvate (pyruvate processing) -> 2 Acetyl - CoA + 2 NADH + 2 CO2
    • = 6 ATP (oxidative)
    • Occurs from cytoplasm into mitochondria
  4. Kreb Cycle (citric acid cycle) -> 2 x (3 NADH + 1 FADH2 + 1 ATP + 2 CO2)
    • = 2 ATP total (substrate)
    • Occurs in mitochondria
  5. Electron transport chain -> 2 x (3 NADH x 3 ATP/NADH = 9 ATP and 1 FADH2 x 2 ATP/FADH2 = 2 ATP) + 2 ATP Total Cell Respiration
    • = 22 ATP​
    • occurs in inner mitochondria matrix
      • Cytochromes = electron carriers (each carrier is reduced as it accepts e- and oxidized as e- is transfered)
      • O2 is the final electron acceptor and forms H2O
  6. Total Aerobic catabolism process = 36 ATP
52
Q

Explain the anaerobic glycolysis pathway

A

No oxygen:

  1. Glucose
  2. Glycolysis = 2 pyruvate + 2 ATP + 2 NADH
  3. Fermentation (Pyruvate = electron acceptor) =
    1. Alcohol fermentation -> ethanol + NAD+ + 2 ATP
    2. Lactic acid fermentation -> lactic acid + NAD+ + 2 ATP
53
Q

When does glycolysis begin?

A

when glucose reacts with hexokinase to form glucose 6 phosphate (2 ATP required for step)

= 2 pyruvate + 2 NADH + 2 ATP (substrate)

produced

54
Q

What occurs in step 4 of glycolysis?

A

Fructose 1,6-biphosphate is split into two three-carbon molecules: dihydroxyacetone phosphate and glycoeraldehyde 3-phosphate (PGAL)

dihydroxyacetone phosphate is then isomerized into PGAL

Therefore two molecules of PGAL produced

55
Q

When does the citric acid cycle (Krebs cycle) begin?

A

When the two-carbon acetyle group from acetyl-CoA combines with oxaloacetate, a four-carbon molecule, to form the six-carbon citrate

Through a series of steps, two CO2 are released and oxaloacetate is regenerated for use in another turn of the cycle

56
Q

Explain carbohydrates as an alternate energy source than glucose

A

Disaccharides are hydrolyzed into monosaccharides, most of which can be converted into glucose or glycolytic intermediates

Glycogen stored in the liver can be converted, when needed, into a glycolytic intermediate

57
Q

Explain fats as an alternate energy source than glucose

A
  • Fat moleules are stored in adipose tissue in the form of triglycerides
    • When needed, they are hydrolyzed by lipases to fatty acids and glycerol and are carried by the blood to other tissues for oxidation
  • Glycerol can be converted into PGAL, a glycolytic intermediate
  • A fatty acid must first be “activated” in the cytoplasm; this process requires two ATP. Once activated, the fatty acid is transported into mitochondria and taken through a series of beta-oxidation cycles that convert it into two-carbon fragments, which are then converted into acetyl-CoA.
    • For each round of beta oxidation, 1 NADH + 1 FADH2 is produced
  • Fats yield the greatest number of ATP / gram
    • Long term energy
58
Q

Explain proteins as an alternate energy source to glucose

A
  • The body degrades proteins only when not enough carbohydrate or fat is available
  • Most amino acids undergo a transamination reaction in which they lose an amino group to form an alpha-keto acid
  • The carbon atoms of most AA are converted into acetyl-CoA, pyruvate or one of the intermediates of the citric acid cycle
  • Oxidative deamination removes an ammonia molecule directly from the amino acid. Ammonia is a toxic substance in vertebrates. Fist can excrete ammonia, whereas insects and birds convert it to uric acid, and mammals convert it to urea for excretion
59
Q

What two components must be present for an enzyme to function? explain

A
  • Enzymes are proteins.
    • Many enzymes are conjugated proteins (proteins that consist of amino acids attached to other groups via covalent bonds)
  • Coenzyme
    • nonprotein component
      • can be metal cations such as Zn2+ or Fe2+ or other small organic groups and vitamins
    • Cofactors that bind to the enzyme by strong covalent bonds are called prosthetic groups
60
Q

What are the two theories for enzymes? explain

A
  1. Lock and Key Theory
    • The spatial structure of an enzyme’s active site is exactly complementary to the spatial structure of its substrate
  2. Induced Fit Theory
    • The active site has a flexible shape that when the appropriate substrate comes in contact with the active site, the conformation of the active site changes to fit the substrate
    • More widely accepted theory
61
Q

Explain enzyme specificity

A
  • Temperature:
    • As temperature increases, the rate of enzyme action increases until an optimum temperature is reached (usually around 40 deg C). Above that temp = deactivation
  • pH:
    • For each enzyme there is an optimum pH. Most of a human optimum = pH 7.2 except stomach pH = 2 and pancreatic enzymes pH =8.5
  • Concentration Enzyme and Substrate:
    • When concentrations of both are low, many of the active sites on enzyme are unoccupied and the reaction rate is low
    • Increases in concentration of substrate will increase the reaction rate until all of the active sites are occupied = Velocity max (Vmax)
62
Q

Explain the difference between Competitive Inhibition and Noncompetitive Inhibition

A
  • Competitive inhibition
    • Molecules that are similar to the substrate bind to the active site of the enzyme
      • If concentration of both the substrate and the similar substrate are the same, they will compete for the active site
    • Because the active site is inhibited by the competitor the enzyme activity is inhibited
    • Substrate can outcompete the competitor and will still be able to reach the Vmax
  • Noncompetitive Inhibition
    • A substance that forms strong covalent bonds with an enzume, making it unable to bind with its substrate, and consequently a noncompetitive inhibitor cannot be displaced by an addition of excess substrate
      • Therefore it is irreversable and never able to reach Vmax
    • ​​A noncompetitive inhibitor may be bound at, near or far from the active site
      • Allosteric inhibition = Other site than active
63
Q

What is the basic unit of heredity?

A

gene

composed of DNA and are located on Chromosomes

64
Q

What was MendelFour Principles of Inheritance?

A
  1. Genes exist in alternative forms (allels). A gene controls a specific trait in an organism
  2. An organism has two alleles for each inherited trait, one inherited from each parent
  3. The two alleles segregate during meiosis, resulting in gametes that carry only one allele for any given inherited trait
  4. If two alleles in an individual organism are different, only one will be fully expressed, and the other will be silent.
    • Expressed = dominent
    • Silent allele = recessive
      • Two copies of same allele = homozygous
      • two different alleles = heterozygous
65
Q

For a test cross, first explain what it is and two what happens if it is crossed with a parent AA or a parent Aa?

A
  • Test cross is an unknown crossed with a homozygous recessive (aa)
  • Test cross x parent AA
    • offspring = Aa = 100% dominant phenotype
  • Test cross x parent Aa
    • offspring = 2 Aa, 2 aa =
      • 50% dominant phenotype
      • 50% Recessive phenotype
66
Q

What is Mendel’s Second Law: Law of Independant Assortments mean?

A

Law of Independant Assortment

Inheritance of one such traite is completely independant of another = dihybrid cross

67
Q

Explain why Drosophila melanogaster were chosen for Mendelian genetic research

A

Drosophila melanogaster = fruit fly

  • It reproduces often (short life cycle)
  • It reporduces in large numbers (large sample size)
  • Its chromosomes (especially in the salivary glands) are large and easily recognizable in size and shape
  • Its chromosomes are few (4 pairs, 2N = 8)
  • Mutations occur relatively frequently
68
Q

Explain Incomplete dominance and codominance

A
  • Incomplete Dominance = blends of the parent phenotype
    • ex. white and red flowers make pink
  • Codominance = when multiple alleles exist for a given gene and more than one of them is dominant.
    • Both dominant alleles are simultaneously expressed
    • ex. ABO blood groups as there are three different alleles: IA, IB and i
      • both IA and IB are dominant and i is recessive
    • Does not include a blend of phenotypes…
69
Q

In sexually differentiated species most chromosomes exist in a pair of homologes called………?

But what are se determination chromosome pair called?

A
  • autosomes
  • Sex chromosomes
70
Q

What are examples of sex-linked recessive in humans?

A

Hemophilia and color-blindness

71
Q

Explain cytoplasmic inheritance and drug resistance

A
  • Heredity systems exist outside the nucleus (ex. DNA found in the mitochondria and other cytoplasmic bodies)
    • Important for determining characteristics of organalles
  • Drug resistance in many microorganism is regulated by cytoplasmic DNA, known as plasmids, that contain one or more genes. Plasmids can be massed from one bacterial cell to another via transformation
72
Q

What is nondisjunction and what are examples of this?

A
  • Either the failure of homologous chromosomes to separate properly during meiosis I or the failure of sister chromatids to separate properly during meiosis II
    • Trisomy (somatic cells will have 2N+1 chromosomes) = three copies of that chromosome
      • Down syndrome = trisomy of chromosome 21
    • Monosomy (somatic cells will have 2N-1 chromosome) = single copy of that chromosome
73
Q

What are mutagenic agents?

A

cosmic rays, X-rays, ultraviolet rays, and radioactivity as well as chemical compounds such as colchicine, which inhibits spindle formation

= carcinogenic (cancer-causing)

74
Q

What are the types of mutations?

A
  • Point mutations = nucleic acid is replaced by another nucleic acid
  • Silent mutation = new codon codes for same amino acid, no change in resulting protein
  • Missense mutation = new codon does for a different amino acid
  • Nonsense mutation = new codon codes for stop codon
  • Frameshift mutation = addition or deletion that shifts down one that causes a complete change in the Amino Acid sequence
75
Q

State and explain two examples of genetic disorders

A
  • Phenylketonuria (PKU)
    • molecular disease caused by the inability to produce the proper enzyme for the metabolism of phenylalanine
    • Individuals are unable to consume products containing aspartame
    • Clinical symptoms: increased concentration of phenylalanine in blood, increased concentration of phenylaline and its by-products in urine and mental retardation
  • Sickle-cell anemia
    • red blood cells become crescent-shaped because they contain defective hemoglobin
76
Q

Explain Bacterial Genome and its replication

A
  • Bacterial Genome:
    • Single circular chromosome located in the nucleoid region of the cell
    • Many bacteria also contain smaller circular rings of DNA called plasmids, containing accessory genes
      • Episomes are plasmids that are capable of integration into the bacterial genome
  • Replication:
    • Begins at a unique origin of replication and proceeds in both directions simultaneously
      • synthesizing 5’ -> 3’
77
Q

Explain Genetic Variance of bacteria

A
  • Bacteria reproduce via Binary Fission
    • Asexual process
  • Have three mechanism for increasing genetic variance of a population:
    1. Transformation
      • foreign chromosome fragment (plasmids) is incorporated into the bacterial chromosome via recombination, creating new inheritable genetic DNA
    2. Conjugation
      • Described like sexual mating and therefore transfers genetic material between two bacteria that are temporarily joined
        • Only bacteria containing plasmids, called sex factors, are capable of conjugating = F factor
          • With Plasmid = F+ , without F-
      • Conjugation between F+ and F- = 2F+
      • Sometimes sex factor becomes integrated into the bacterial genome and during conjugation the bridge breaks before entire transformation = Hfr cells = high frequency of recombination
    3. Transduction
      • bacteriophage is a virus that infects its host bacterium by attaching to the bacterium, boring a hole through the bacterial cell wall, and injecting its viral DNA while its protein coat remains attached to the cell wall.
      • Transduction occurs when fragments of the bacterial chromosome become packaged into the viral progeny produced during such a viral infection
        • The closer two genes are to one another ona chromosome, the more likely they will be to transduce together; that fact allows geneticsts to map genes to a high degree of percision
  • Recombination:
    • Occurs when linked genes are separated, breaks and rearranges
78
Q

Explain bacterial gene regulation and the two types

A
  • Gene regulation:
    • Regulation of transcription and allows them to control metabolism
      • based on the accessibility of RNA polymerase to genes being transcribed and is directed by an operon, which consists of structural genes, and operator region and a promoter region on the DNA before the protein coding gene
        • Operator = sequence of nontranscribable DNA = repressor binding site
        • Promotor = noncoding sequence of DNA that surves as the initial binding site for RNA polymerase
        • regulator gene, which codes for the synthesis of a repressor molecule that binds to the operator and blocks RNA polymerase
  • Inducible systems
    • Require the presence of a substance, inducer, for transcription to occur
      • repressor binds to operator = no transcription (bound to operator)
      • inducer bind to repressor = transcription
        • Inducer-repressor complex formed and cannot bind to operator to inhibit transcription
  • Repressible systems
    • are in a constant state of transcription unless a corepressor is present to inhibit transcription
      • repressor + corepressor = no transcription (bound to operator)
        • ​corepressors are often end products of biosythetic pathways they control
      • repressor only = transcription
79
Q

What was Lamarckian Evolution theory vs. Darwin’s?

A
  • Lamarckian = use or disuce and acquired characteristics
    • ex. Long necks of giraffs?
  • Darwin = fitness to survive and reproduce
80
Q

What were the outlined basic agents that Darwin determined lead to evolutionary change = natural selection

A
  1. Overpopulation:
    • more offspring are produced than can survive
  2. Variations:
    • Offspring naturally showed variation/differences in their characteristics compared to those of their parents. beneficial mutations
  3. Competiton:
    • compete for necessities of life
  4. Natural selection:
    • some organisms have variations that give them advantages over other members of the species
  5. Inheritance of the variations:
    • individuals that survive live to adulthood to reporduce and thus transmit these favorable variations
  6. evolution of new species:
    • over generations of natural selection, the favorable changes (adaptations) are perpetuated in the species
81
Q

What is speciation?

What are demes?

A
  • Speciation:
    • is the evolution of new species, which are groups of individuals that can interbreed freely with each other but not with members of other species
  • Demes
    • before speciation, small, local populations form within a species
      • if these demes become isolated, speciation may occur
82
Q

Explain the types of evolution paths

A
  • Biologists seek to understand the evolutionary relationships among species alive today, evolutionary history = phylogeny
  • branches:
    1. Convergent evolution: groups develop in similar ways when exposed to similar environments
    2. Parallel evolution: similar to convergent evolutionbut occurs when a more recent ancestor can be identified
    3. Divergent evolution: occurs when species with a shared ancestor develop differing traits due to dissimilarities between their environments
83
Q

Explain the conditions that the Hardy-Weinberg Principle MUST follow

A
  • The population is very large
  • No mutations affect the gene pool
  • Mating between individuals in the population is random
  • There is no net migration of individuals into or out of the population
  • The genes in the population are all equally successful at reproducing
84
Q

State the Hardy-Weinberg Equation

A

p + q = 1

(p + q)2 = 12

p2 + 2pq + q2 = 1

where: p = frequency of dominant

q = requency of recessive

85
Q

Explain the Evidence of Evolution

A
  • Fossil Record: Direct evidence
    • Types of fossils: teeth, bones, in rocks, tar pits, ice and amber (fossil resin of trees), Petrification = minerals replace the cells of organisms, imprints, molds and casts
  • Comparative Anatomy:
    • Homologous Structures: structures that have the same basic anatomical features and evolutionary origins
    • Analogous Structures: structures with similar functions but may have different evolutionary origins and entirely different patters of development
  • Comparative Embryology:
    • Stages of development of the embryo resemble the stages in an organism’s evolutionary history
      • two-layer gastrula = similar to hydra, a cnidarian
      • Three-layer gastrula = similar to flatworm
      • The earlier the stage at which it diverges, more dissimilar
  • Comparative Biochemistry (physiology):
    • Most organisms demonstrate the same basic needs and metabolic processes, require nutrients, similar organelles and ATP energy
  • Vestigial Structures:
    • Have no known current function but apparently had some ancestral function
86
Q

Explain the heterotroph hypothesis for origin and early evolution of life

A
  • First forms of life lacked the ability to synthesize their own nutrients = heterotrophs
    • depended upon outside sources of food
  • Primitive seas containsed simple inorganic and organic compounds such as:
    • salts, methane, ammonia, hydrogen and water
    • energy = heat, electrocity, solar radiation (X-rays and UV), cosmic rays and radioactivity
87
Q

Explain Primordial soup and formation and evidance of organic synthesis

A
  • The presence of building blocks (salts, methane, ammonia, hydrogen, water and energy) may have led to the synthesis of simple organic molecules
    • sugars, amino acids, purines and pyrimidines. these molecules dissolved in the “primordial soup”
    • after many years, the simple monomeric molecules combined to form a supply of macromolecules
  • Evidence of organic synthesis:
    • An aparatus was set up with the primordial soup ingredients on early eart to see if macromolecules could develope and they did
  • Formation of primative cells:
    • Colloidal protein molecules tend to clump together to form coacervate droplets.
      • droplets tend to posses a definite internal structure and highly likely that they developed on early earth
88
Q

Explain the development of Autotrophs

A
  • The primitive heterotrphs slowoly evolved complex biochemical pathwyas, enabling them to use a wider variety of nutrients
  • Evolved anaerobic respiration processes to convert nutrients to energy however, needed nutrients faster than the environment could provide
    • Autotrophs are able to produce organic compounds, including energy-containing molecules, from substances in their surroundings
89
Q

What are the four general categories that living organisms can divide into? name and describe a type

A
  • Autotrophic anaerobes = chemosynthetic bacteria
  • Autotrophic aerobes = green plants and photoplankton
  • Heterotrophic anaerobes = yeast
  • Heterotrophic aerobes = amoebas, earthworms and humans
90
Q

What are homologous structures?

A

similar in origin but not necessarily in function

91
Q

As the ociean became saltier, whales and fish independently evolved mechanisms to maintain the concentration of salt in their bodies. what type of evolution explains this?

A

convergent

92
Q

In a particular Hardy-Weinberg population, there are only two eye colors: brown and blue. thirty-six percent of the population has blue eyes, the recessive trait. What percentage of the population is heterozygous for brown eyes?

A

The percentage of the population with blue eyes (genotype = bb) = 36% = q2 = 0.36; therefore q = 0.6

because p + q = 1 , p = 0.4

the frequency of heterozygous brown eyes is

2 p q = 2 (0.4) (0.6) = 0.48 = 48% is heterozygous for brown eyes

93
Q
A

DAT Study Cards (5 decks)

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