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General Biology 1 > Final Exam > Flashcards

Final Exam Flashcards

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1
Q

SELECTED REVIEW QUESTION

Define homeostasis.

A

all organism maintain relatively constant internal conditions that are different from their environment

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2
Q

SELECTED REVIEW QUESTION

How are living systems organized? What characteristics do all organisms share?

A
  1. Cellular (atoms, molecules, organelles, cell) organismal (tissue, organ, organism) population (population, community), ecosystem, biosphere
  2. Cellular organization; ordered complexity; sensitivity; growth, development, and reproduction, energy utilization, homeostasis, evolutionary adaptation
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3
Q

SELECTED REVIEW QUESTION

Compare experimental and control variables.

A

Experimental variable - variable that is altered/changed/manipulated
Control variable - variable that is kept constant/not changed

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4
Q

SELECTED REVIEW QUESTION

What is meant by homologous trait? Provide an example

A

A trait with the same evolutionary origin, but different structure and function. E.g., the arms of humans, cats, bats, and horses

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5
Q

SELECTED REVIEW QUESTION

What is occurring in a redox reaction?

A

The coupling of oxidation and reduction. An atom or molecule is oxidized, meaning it loses an electron, while another is reduced, meaning in it gains an electron, in the same reaction.

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6
Q

SELECTED REVIEW QUESTION

Describe the following chemical bonds; hydrophobic interaction, ionic bond, covalent bond, hydrogen bond.

A

Hydrophobic interaction - forcing of hydrophobic portions of molecules together in presence of polar substances

Ionic bond - atoms with opposite electrical charges (ions) attract

Covalent bond - two atoms share one or more pairs of electrons

Hydrogen bond - sharing of H atom

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7
Q

SELECTED REVIEW QUESTION

Compare polar and nonpolar molecules.

A

Polar - electrons are not shared equally due to differences in electronegativity
- results in regions of partial negative charge near more electronegative atom, and regions of partial positive charge near less electronegative atom

Nonpolar - equal sharing of electrons
- affinity for electrons is the same between atoms

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8
Q

SELECTED REVIEW QUESTION

What influences the rate of chemical reactions?

A
  1. Temperature
  2. Concentration of reactants and products
  3. Catalysts
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9
Q

SELECTED REVIEW QUESTION

Understand the chemical properties of water, and the different emergent properties that result from them.

A
  1. Cohesion - polarity of water allows water molecules to be attracted to one another
    - responsible for water being liquid (not a gas) at moderate temps
  2. High specific heat - the amount of heat 1g of a substance must absorb or lose to changes its temperature by 1 C.
    - measures extent to which a substance resist changing its temperature when it absorbs or loses heat
  3. High heat of vaporization - amount of energy required to change 1g of a substance from a liqduid to a gas
  4. Lower density of ice - ice is less desne than liquid water because ydrogen bods in ice space water molecules far apart
  5. Solubility - polar water molecules are attracted to ions and polar compounds, making these compounds soluble
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10
Q

SELECTED REVIEW QUESTION

What is the relationship between dehydration and hydrolysis reactions?

A

Dehydration reactions - links monomers together to form polymers
- releases a water molecule for every bond formed

Hydrolysis - disassembles polymers into monomers
- adds a water molecule (reverses loss of water molecule)

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11
Q

SELECTED REVIEW QUESTION

Why do phospholipids form membranes and triglycerides don’t? OR Why do phospholipids spontaneously form bilayers?

A

Phospholipids spontaneously form bilayers due to their amphipathic structure. The term amphipathic describes molecules with hydrophilic and hydrophobic parts. In the case of phospholipids, their structure includes polar heads, which are hydrophilic, and nonpolar hydrocarbon tails, which are hydrophobic.

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12
Q

SELECTED REVIEW QUESTION

Explain how the structure of different macromolecules we learned about determines their function.

A
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13
Q

SELECTED REVIEW QUESTION

What type of bond joins two amino acids/nucleotides/saccharides together?

A

Amino acids - peptide bonds
Nucleotides - phosphodiester bonds
Saccharides - covalent bonds

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14
Q

SELECTED REVIEW QUESTION

Why is homeostasis of cellular conditions important for enzyme function?

A

Enzymes have very narrow range of environmental conditions. If enzymes experienced conditions outside of their normal range, such as excessive tempteratures of high pH, the enzyme’s natie configuration would be lost, a process known as denaturation. When proteins, like enzymes, become denatured, they are biologicall inactive, meaning they can not carry out their functions.

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15
Q

SELECTED REVIEW QUESTION

Why are cells small?

A

When cells are small, they are able to diffuse substances into and out the cell much more efficiently than cells that are larger. This is because larger cells have a greater surface area to volume ratio, meanin that when cell size increases, its volume increases more rapdily than its surface area, which increases the lenght of time substances diffuse across the cell. This as a conseuqnece will lead to higher energy demands, more marcomolecules to syntehsize, and a greater quantity of waste.

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16
Q

SELECTED REVIEW QUESTION

What affects the rate of diffusion in and out of a cell?

A
  1. Surface area
  2. Temperature
  3. Concentration gradient of diffusing substance
  4. Distance
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17
Q

SELECTED REVIEW QUESTION

What structural features do all cells share?

A
  1. Nucleoid or nucleus where genetic material is located
  2. Cytoplasm
  3. Ribosomes
  4. Plasma membrane
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18
Q

SELECTED REVIEW QUESTION

Defining features of Prokaryotic v. Eukaryotic cells; Plant v. Animal cells.

A

Prokaryotes:
- lack a nucleus
- cell wall (peptidoglycan)
- singular circular chromosome

Eukaryotes:
- nucleus
- membrane-bound organelles
- endoplasmic reticulum
- multiple linear chromosomes

Plant cells:
- cell wall (cellulose)
- chloroplasts
- plasmodesmata
- vacuoles; central vacuole

Animals:
- extracellular matrix (ECM)
- gap junctions

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19
Q

SELECTED REVIEW QUESTION

Describe the structure of transmembrane proteins.

A

Transmembrane domain - hydrophobic region of transmembrane protein that anchors it in membrane (composed of hydrophobic amino acids arranged into alpha helices)

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20
Q

SELECTED REVIEW QUESTION

What is Osmosis? Know the terms: hyper-, hypo- and isotonic.

A

Net diffusion of water across a membrane toward a higher solute concentration

Free water molecules move down their concentration gradient toward higher solute concentration

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21
Q

SELECTED REVIEW QUESTION

What happens to a cell in hypo-, hyper-tonic solution?

A

Hypotonic solution:
- solution with a lower concentration of solutes than cell
- water diffuses into cell from extracellular fluid
- cytoplasm is hypertonic relative to extracellular fluid
- causes cell to swell

Hypertonic solution:
- solution with a higher concentration of solutes than cell
- water diffuses out of cell
- cytoplasm is hypotonic relative to extracellular fluid
- causes cell to shrink

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22
Q

Describe polarity. Why are some molecules polar and others are not?

A
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23
Q

What is an emergent property? Can you describe an example?

A

novel properties arising from the way in which components interact; often cannot be deduced solely from knowledge of the individual components

These properties arise from the collaborative function of a system, but cannot be attributed to any one part of the system .

Example:
- DNA: looking at genetic code alone cannot predict of the things that make up an individual.

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24
Q

How does the structure of water molecules facilitate hydrogen bonding?

A

Water’s structure consists of two partial negative charges near oyxgen and two partial charges near each hydrogen. This difference in electronegativity is what makes a water molecule polar. This polarity allows water molecules to form hydrogen bonds, where the positively charged hydrogen of one molecule is attracted to the negatively charged oxygen of another molecule.

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25
Q

How do the structures of starch and cellulose affect their function?

A

Starch is known as a storage polysaccharide. It is made up alpha-glucose chains.

Cellulose is known as a structural polysaccharide. It is made up of beta-glucose chains

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26
Q

What features do hydrocarbons, carbohydrates and lipids share that make them good energy storage molecules?

A

All contain a high proportion carbon-hydrogen (C–H) bonds

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27
Q

In what way does the primary structure of a protein affect its tertiary structure, and ultimate function?

A

The primary structure comprises the amino acid sequence of a protein. The most important aspects that differentiates these amino acids is the R group. What makes the primary structure so fundamental to the overall shape of a protein is when the amino acid sequence is altered, the tertiary structure has to go through modifications as well. This is because in the tertiary structure, the R groups of amino acids go through bonding, and if the amino acid sequence is changed even slightly, this will change the R groups that are bonded together. They may not even bond together.

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28
Q

How does the structure of beta-barrels allow the passage of polar molecules? Think about the secondary and tertiary structure of the proteins specifically. What might you expect to see at these levels of protein structure?

A

The beta-barrel is a motif

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29
Q

In what cells would you expect to have a higher ratio of RER? SER? Explain your reasoning.

A

Cells with a higher ratio of RER are cells that synthesize proteins, such as antibodies, because RER is rough because its abundance of ribosomes, which perform the role of protein sysnthesis. Cells with a higher ratio of SER are cells in the testes, intestine, and brain, because these areas carry out extensive lipid synthesis, because one of the main functions of SER is to synthesize lipids and steroid hormones.

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30
Q

SELECTED REVIEW QUESTION

How does energy enter an ecosystem?

A

Sun

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31
Q

SELECTED REVIEW QUESTION

What are the first laws of thermodynamics?

A

Energy cannot be created or destroyed; it can only change from one form to another

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32
Q

SELECTED REVIEW QUESTION

What is meant by a change in free energy?

A

A change in free energy describes how reactions break bonds in reactants and form new ones in products, which results in changes in free energy.

This change is symbolized by the delt symbol.

Change in free energy is calculated as energy of products minus energy of reactants

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33
Q

SELECTED REVIEW QUESTION

What is the difference between endergonic and exergonic reactions?

A
  1. Endergonic - products contain more energy than reactants
  2. Exergonic - products contain less energy than reactants
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34
Q

SELECTED REVIEW QUESTION

What is activation energy?

A

Energy that must be processed by a molecule in order for it to undergo a specific chemical reaction

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35
Q

SELECTED REVIEW QUESTION

How can the rate of a reaction be increased?

A
  1. Increasing energy of reacting molecules
  2. Lowering activation energy
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36
Q

SELECTED REVIEW QUESTION

What is the structure of ATP? How does it store energy?

A
  1. Ribose (5-carbon sugar)
  2. Adenine
  3. Three phosphates

Stores energy within its triphopshate

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37
Q

SELECTED REVIEW QUESTION

Compare anabolic and catabolic metabolism.

A

Anabolism - chemical reactions that expend energy to build up molecules

Catabolism - chemicals reactions that harvest energy by breaking down molecules

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38
Q

SELECTED REVIEW QUESTION

What benefit do biochemical pathways provide to the cell?

A
  • not making energy when you have enough energy
  • not wasting energy/chemical resources
  • only active when products are needed
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39
Q

SELECTED REVIEW QUESTION

What is the role of NAD+ in cellular respiration?

A

Acts as electron acceptors and release the energy from the electrons into the ETC

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40
Q

SELECTED REVIEW QUESTION

Draw out glycolysis, CAC and the ETC.

A

Glycolysis:
- takes place in cytoplasm
- anaerobic (no oxygen)
- Glucose is split into two G3P
- 2 G3P becomes two pyurvate
- Two ADP molecules are converted into ATP
- Two NAD+ molecules are reduced to NADH

  • Pyruvate is transported into mitochondria
  • pyruvate is oxidized to an acetyl group
  • acetyl group binds to coenzyme A -> acetly-CoA
  • acetly-CoA is fed into CAC

CAC:
- matrix of mitochondria
- acetly-CoA + oxaloacetate = citrate
- citrate -> isocitrate (6C; isomer of citrate) -> a-ketoglutarate (5C) -> succinyl-CoA (4C) -> succinate (4C) -> fumarate (4C)-> malate -> oxaloacetate
- NAD+ is reduced to NADH
- FADH is reduced to FADH

ETC:
- inner membrane of mitochondria
- NADH + FADH2 are oxidized (release e-)
- NADH dehydrogenase - first carrier in ETC
- FADH2 feeds electrons to ubiquinone (skips first step)
- Ubiqiunone passes e- to bc1 complex
- Cytochrome c carries e- to cytochrome oxidase complex
- Protons pumped out of matrix into intermembrane space
- Chemiosmosis occurs
- ATP synthase uses protons to synthesize ATP

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41
Q

SELECTED REVIEW QUESTION

What are examples of negative feedback in Cell Respiration?

A

If NADH is not oxidized fast enough: NADH levels rise and inhibit pyruvate dehydrogenase –> prevents conversion of pyruvate to acetyl-CoA

Citric Acid Cycle: high amounts of ATP shuts down CAC and acetyl-CoA is channeled into fat synthesis

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42
Q

SELECTED REVIEW QUESTION

What drives the proton pumps in the ETC?

A

The electrons released by the electron carriers (NADH and FADH2), which drives the protons out of the matrix and into the intermembrane space.

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43
Q

SELECTED REVIEW QUESTION

Explain how cellular respiration is a catabolic process whereas photosynthesis is an anabolic process.

A

In a catabolic reaction, energy is being harvest by breaking down molecules. In the context of cellular respiration, molecules are being oxidized and broken down into smaller molecules. For example, glucose is eventually split into two pyruvate. The end of glycolysis also yields two NADH and two net ATP. these two NAD+ have been reduced after accepting electrons from oxidized molecules. This energy through glycolysis and the CAC will build up the energy which will then be released into the ETC, which help drive ATP synthase to produce ATP molecules, which are forms of energy.

In an anabolic reaction, energy is expended in order to build up molecules. Photosynthesis best shows this type of reaction, because instead of breaking down glucose, the Calvin cycle is using CO2 and RuBP to create 2 G3P, which can then be used to combine into a molecule of glucose.

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44
Q

SELECTED REVIEW QUESTION

What is the primary difference between the ‘light-reactions’ and the Calvin cycle? Describe what is happening in both processes

A

Light-reactions - use energy in sunlight to make ATP and reduces NADP+ to NADPH
1. Photosystem II absorbs photons, exciting electrons that are passed to plastoquinone.

  1. b6-f complex receives electrons from PQ and passes them to plastocyanin and carries them to photosystem I
  2. Photosystem I absorbs photons, exciting electrons that are passed to ferrodoxin and then to NADPH
  3. ATP synthase

Calvin cycle - use ATP and NADPH from light-reactions to produce organic molecules from CO2
1. Carbon fixation:
- CO2 reacts with RuBP to form two 3PG

  1. Reduction: 3PG is reduced to G3P
  2. Regeneration of RuBP: 3PG is used to regenerate RuBP
  • G3P can be converted to glucose
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45
Q

SELECTED REVIEW QUESTION

What is meant by carbon fixation.

A

Formation of organic molecules from CO2

46
Q

SELECTED REVIEW QUESTION

What are the four types of cell signaling? Compare and contrast.

A
  1. Direct contact - molecules on surface of one cell are recognized by receptors on adjcanet cell (e.g., jap junctions)
    - signals are shorter lived; travelling less distance
  2. Paracrine signaling - secretions from one cell have an effect only on cells in the immediate area/neighboring cells (e.g., signaling between immune cells)
    - short lived, local effects
  3. Endocrine signaling - hormones are released into organism’s circulatory system, which carries them to target cells (e.g., hormones)
  4. Synaptic signaling - nerve cells receive signals, whcih binds to receptor on nearby cells (e.g., neurotransmitter)
    - short lived; target cells in close proximity to neuron
47
Q

SELECTED REVIEW QUESTION

Define signal transduction pathway.

A

In signal transduction, a ligand binds to its receptor protein. This creates pathways that lead to cellular responses in the cell.

48
Q

SELECTED REVIEW QUESTION

Compare intracellular receptors and membrane receptors?

A

Intracellular receptors:
- bind to hydrophobic ligands
- receives signals from lipid-soluble or noncharged, nonpolar small molecules

Cell-surface/membrane receptors:
- bind to hydrophilic ligands

49
Q

What affects the rate of enzyme catalyzed reactions?

A
  1. Temperature
  2. pH
  3. Inhibitors and activators
50
Q

What is meant by feedback inhibition and why is it important for the cell?

A

Feedback inhibition is when the end-product of the pathways becomes the allosteric inhibitor by binding to the allosteric site of the first enzyme in the pathway

51
Q

Can a catalyst make an endergonic reaction exergonic?

A

No, it can only make it faster.

52
Q

Why is ATP not a good long-term storage molecule? Focus on structure and function.

A

Instability of phosphate bonds in ATP. Phosphate groups are highly negatively charged and strongly repel one another

53
Q

Explain how NADH (and FADH2) relate to ATP synthesis.

A

NADH and FADH2 collect electrons and release them into the electron transport chain, which helps drive the proton pump for ATP synthase, synthesizing ATP. This way of making ATP is known as oxidative phosphorylation

54
Q

Explain the relationship between Protein Kinases and Phosphatases.

A

Protein kinase - class of enzyme that adds a phosphate to proteins

Phosphatase - class of enzyme that removes phosphate groups from proteins

55
Q

In what ways are Cellular Respiration and Photosynthesis connected, in reference to their products and reactants? Make sure you give at least one specific example of a product/reactant involved in both pathways.

A

Cellular respiration and photosynthesis both utilize glucose. Cellular respiration uses glucose as a reactant to make products such as pyruvate in Glycolysis, which is further oxidized into acetyl-CoA, which is then utilized as a reactant in the citric acid cycle. Photosynthesis uses reactants such as CO2, to make glucose as a product, specifically during the Calvin cycle.

56
Q

SELECTED REVIEW QUESTION

What does ploidy number refer to? What is haploid? What is diploid?

A

Ploidy - number of set chromosomes an organism has

Haploid (n) - one complete set of chromosomes

Diploid (2n) - total number of chromosomes; two sets of identical chromosomes

57
Q

SELECTED REVIEW QUESTION

Describe the structure of Chromosomes and Chromatin; understand how its structure changes throughout the cell cycle.

A
  • Chromosomes are composed of chromatin
  • ## Chromatin is a complex of DNA and protein
58
Q

SELECTED REVIEW QUESTION

What is implied when a protein is highly conserved?

A

When a protein is referred as highly conserved, it is implying that a protein has remain unchanged throughout its evolution. An example of this would be histone proteins, which play a role in the structure of the nucleosome.

59
Q

SELECTED REVIEW QUESTION

What happens in Interphase? What are the main events in each phase?

A

G1:
- cells undergo major portion of their growth (i.e., primary growth phase)

S:
- DNA is replicated

G2:
- chromosomes begin to condense
- microtubules begin to reorganize to form a spindle

60
Q

SELECTED REVIEW QUESTION

What happens in M Phase? What are the main events in each phase?

A

Prophase:
- Chromosomes become condensed and become visible
- Cytoskeleton disassembles
- Spindle apparatus forms
- Nuclear envelope breaks down

Metaphase:
- chromosomes align at equator of cell (metaphase plate)

Anaphase:
- proteins holding sister chromatids together at centromere are removed

  • Anaphase A: kinetochores are pulled toward the poles
  • Anaphase B - poles move apart

Telophase:
- spindle apparatus disassembles
- nucleus envelopes reform around chromosomes

61
Q

SELECTED REVIEW QUESTION

Describe the structure and function of the Spindle Apparatus.

A

Structure: composed of microtubules (spindle fibers)

Function: carries out separation of chromosomes during cell division

62
Q

SELECTED REVIEW QUESTION

For each of the 3 checkpoints: When do they occur? Why do they occur when they do? What causes the cell cycle to stop at each?

A

G1/S checkpoint:
- occurs when cell decides whether or not to divide
- stops when there is damage to DNA, lack of growth factors, and starvation conditions

G2/M checkpoint:
- occurs when assessing success of DNA replication
- stops when DNA has not been replicated accurately

Spindle checkpoint:
- occurs when ensuring all chromosomes are attach to spindle in preparation for anaphase
- stops when sister chromatids are not attached correctly spindle

63
Q

SELECTED REVIEW QUESTION

How do cells know when to divide?

A

Cells know when to divide through the influence of their environment, growth factors, such as MPF, and cyclin-dependent kinases (Cdks), which work along side MPF. This is true because when there is a lack of growth factors and there are starvation conditions in the environment, the cell will not proceed with the first checkpoint of the cell cycle: G1/S checkpoint.

64
Q

SELECTED REVIEW QUESTION

Compare somatic cells and gametes. How do their genomes vary? Where are they found in animals (humans)?

A

Somatic cells:
- diploid nonreproductive cells
- Two sets of chromosomes are present
- can be found anywhere in the body
- mitosis

Gametes:
- haploid reproductive cells
- Only one set of chromosomes is present
- only found in egg and sperm
- meiosis

65
Q

SELECTED REVIEW QUESTION

What happens during fertilization, specifically in terms of c’some number?

A

Fertilization is a process involving the fusion of gametes, which are haploid, to produce a new cell, called a zygote, which is diploid. During this process, the zygote is receiving haploid chromosomes from both the mother and the father. Since a haploid is only one set of chromosomes, which in humans is 23, these chromosomes fusing together will produce a cell that has two sets of chromosomes, making the cell diploid. This ensures that cells do not exceed beyond the normal number of chromosomes, which in humans is 46.

66
Q

SELECTED REVIEW QUESTION

Generally, what is Meiosis? What it the primary function of Meiosis? What types of cells are being formed at the end of meiosis?

A

Meiosis is a reduction division process that occurs during gamete formation, and produces cells with half the normal number of chromosomes, in other words, cells that are haploid.

The primary function of meiosis is to reduce the number of chromosomes in gametes, so when they fuse to make a zygote, the cell returns to the normal number of chromosomes.

The types of cells being formed once meiosis is completed are four haploid daughter cells. These cells will go on to be gametes, or the reproductive cells of the body, such as eggs and sperm.

67
Q

SELECTED REVIEW QUESTION

Compare Meiosis I and II.

A

Meiosis I:
- homologous chromosomes become closely associated through a process called synapsis
- homologous chromosomes align along metaphase plate (metaphase I)
- sister chromatids remained connected and segregate together to opposite poles (anaphase I)

Meiosis II:
- synapsis and crossing over does not occur
- sister chromatids pull toward opposite poles (anaphase II)

68
Q

SELECTED REVIEW QUESTION

Why are homologous chromosomes pairing in Prophase I?

A

Homologous pairing of chromosomes allows crossing over to occur, a process in which chromosomes exchange segments of each other. And since the chromosomes are closely associated, chromosomes are able to remain intact during anaphase I. Since the chromosomes have exchanged genetic material and are now in separate cells, the sister chromatids will separate during anaphase II, creating a large range of genetic diversity. Without the initial step of homologous pairing, none of this would occur.

69
Q

SELECTED REVIEW QUESTION

What is Crossing over? How/ when does it occur? Why is it important and what does it result in?

A
  • homologues exchange chromosomal material
  • Occurs during prophase I
  • results in genetic diversity
70
Q

SELECTED REVIEW QUESTION

Outline the basic structure of Mendel’s experimental design.

A
  1. Produce true-breeding lines for each trait he was studying
  2. Cross-fertilize true-breeding strains having alternate forms of a trait
  3. Allow the hybrid offspring to self-fertilize for several generations and count the number of offspring showing each form of the trait
71
Q

SELECTED REVIEW QUESTION

Draw out a Monohybrid cross – what parentage of the F1 have the dominant phenotype? What is the Phenotyptic ratio? Genotypic ratio?

A
  • 100%
  • 3:1
  • 1:2:1
72
Q

SELECTED REVIEW QUESTION

Define: allele, homozygous, heterozygous, genotype, phenotype

A

Allele - different variations of a gene

Homozygous - an individual that possesses two identical allels

Heterozygous - an individual that possesses two dissimilar alleles

Genotype - total set of alleles an individual contains

Phenotype - physical appearance of an individual

73
Q

SELECTED REVIEW QUESTION

How can different genotypes result in the same phenotype? Or Why does the 1:2:1 genotype ratio – appear as the 3:1 phenotype ratio?

A

The 1:2:1 genotype ratio consists of dominant homozygous, heterozygous, and recessive homozygous. The 3:1 phenotype consists of 3 dominant 1 recessive. The answer is in the heterozygous condition in the 1:2:1 genotype ratio. Because a dominant trait can be expressed in both the heterozygous and homozygous condition, while recessive is only expressed in the homozygous condition, the heterozygous will always display the dominant allele in the phenotype, because while consists of both a dominant and recessive, and dominant outshines the recessive

74
Q

SELECTED REVIEW QUESTION

What is the principle of segregation? What is the principle of independent assortment?

A

Principle of Segregation - two alleles for a gene segregate during gamete formation and are rejoined at random, one from each parent, during fertilization. I.e., alternative alleles for a character segregate from each other during gamete formation and remain distinct.

Principle of Independent Assortment - in a dihybrid cross, the alleles of each gene assort independently. I.e., segregation of different allele pairs is independent

75
Q

SELECTED REVIEW QUESTION

Why would Aneuploidy in sex chromosomes be less severe than in autosomes?

A

The reason aneuploidy in sex chromosomes would be less severe than in autosomes is because sex chromosomes do not contain nearly as many functional genes as autosomes do. Majority of the time, people with aneuploidy in sex chromosomes are still born with normal features, still reach maturity, and overall retain most normal functioning. For example, in the disorder Triple X, or XXX, females have an extra X chromosome, but show no signs of disability, impairment or disease. The only thing that distinguishes them from anyone else is only one of the X chromosomes is functional, and the other two are Barr bodies, meaning the other X chromosomes are inactivated. In autosomes, however, aneuploidy can be much more catastrophic. For example, trisomy on chromosome 21, an autosome, results in Down syndrome. Continuing with trisomy, an extra autosomes on chromosomes 13, 15, or 18 can result in severe defects at birth, and the infant will likely not live for more than a few months.

76
Q

SELECTED REVIEW QUESTION

What are Chargaff’s rules?

A
  1. Amount of adenine always equals amount of thymine; amount of guanine always equals amount of cytosine
  2. Ratio of G-C and A-T varies with different species
77
Q

SELECTED REVIEW QUESTION

Describe complementary base-pairing.

A

Base-pairs are complementary pairs bases, in particular a purine and a pyrimidine. For example, adenine always pairs with thymine because adenine is a purine and thymine is a pyrimidine. If two purines, like adenine and guanine, were paired, the pairs would be too wide. Describing these base-pairs as complementary means that every sequence of bases has a complementary sequence. Going back to the base pairs, if the first base in the sequence was cytosine, the complementary base would begin with guanine.

78
Q

SELECTED REVIEW QUESTION

Compare/contrast DNA and RNA polymerase.

A

DNA polymerase:
- add bases to 3’ end of existing strands
- synthesize in a 5’-to-3’ direction
- requires a primer

RNA polymerase:
- synthesizes primers

79
Q

SELECTED REVIEW QUESTION

Describe the antiparallel configuration of the double helix.

A

The antiparallel configuartion of the double helix describes to the opposite polarity of the DNA strands, meaning that the two strand’s polarities run in different directions. For example, if one strand has a polairty of 5’-3’, the other strand would have a polairty of 3’-5’.

80
Q

SELECTED REVIEW QUESTION

How are the two strands of a double helix held together?

A

The two strands are held together by hydrogen bonds between bases on opposite strands.

81
Q

SELECTED REVIEW QUESTION

What is meant by semiconservative replication?

A

Semicontinuous replication describes the way DNA strands are synthesized. The leading strand, for example, is synthesized contiously from an initial primer, while the lagging strand is sytnehsized discontionusly, requiring multiple pirming events. This continuous-disocontinous way of synthesizing averages to a semicontinous replication of DNA strands.

82
Q

SELECTED REVIEW QUESTION

Describe the events of (1) Initiation, (2) Elongation and (3) Termination in E.coli?

A

Initiation:
- replication begins in origin of replication (oriC)

Elongation:

Termination:

83
Q

SELECTED REVIEW QUESTION

Why is the lagging strand replicated differently than the leading strand?

A

Polymerases can synthesize DNA in only one direction (5’-3’), and the two DNA strands run in opposite directions (polarity - 5’-3’ and 3’-5’). This means that only the leading strand can be synthesized contiously because it follows the direction of synthesis, will the lagging strand does not, meaning it needs to be synthesized into fragments called Okazaki fragments each with its own primer.

84
Q

SELECTED REVIEW QUESTION

Why is replication of eukaryotic chromosomes more complicated than prokaryotic? And how do eukaryotic cells overcome these challenges?

A

Eukaryotes:
- larger amount of DNA organized into multiple chromosomes
- linear structure of chromosomes

85
Q

If the number of c’somes was not reduced prior to gamete formation, what would happen to the number of c’somes within the zygote?

A

Chromosome number would double with each fertilization, and after only a few generations, the number of chromosomes in each cell would become impossibly large

86
Q

Compare Euchromatin and Heterochromatin, how do they differ functionally?

A

Euchromatin - active domains of chromatin

Heterochromatin - inactive domains of chromatin

87
Q

In detail explain the primary differences between Mitosis and Meiosis?

A

Mitosis:
- produces two diploid cells
- single nuclear division after DNA replication

Meiosis:
- homologous pairing
- crossing over
- two nuclear divisions with no DNA replication between them
- produces four haploid cells

88
Q

If females have double the X-genes, do they express twice as many proteins encode on the X c’somes? Why or why not.

A

No, because of dosage compensation. This ensures an equal level of expression from sex chromosomes despite a differing number of sex chromosomes in males and females. This is accomplished by inactivating one of the X chromosomes in females, making it a Barr body.

89
Q

Can individuals have more than two alleles for a gene, why or why not?

A

No.

90
Q

What is meant by polarity in reference to DNA structure and replication?

A

Polarity refers to relationship of the two ends of a DNA strand: 3’ (hydroxyl) end and 5’ (phosphate) end. These ends can be oriented either 5’-3’ or 3’-5’.

91
Q

What is meant by the statement, “A newly synthesized DNA strand is complementary to the parent strand, not identical”

A

This statement described the complementary base-pairing that occurs between DNA strands. For example, if the parental strand begins with TCAG, the other strand would be AGTC.

92
Q

QUIZ QUESTION

An atom with 8 protons, 8 electrons, and 7 neutrons is positively charged

A

False

93
Q

QUIZ QUESTION

Oil does not mix in water due to

A

Hydrophobic exclusion

94
Q

QUIZ QUESTION

For the following atoms, determine if they are reactive or non-reactive (inert)

A

Flourine (7 valence electrons) - reactive
Neon (8 valence electrons) - inert
Sodium (1 valence electron) - reactive

95
Q

QUIZ QUESTION

In 2-3 sentences, explain why water is a polar covalent bond.

A

Water is a polar covalent bond because oxygen has a greater electronegativity than hydrogen, so they do not share valence electrons equally. Oxygen pulls more of the electrons, resulting in a partial negative charge, while hydrogen ends up with a partial positive charge.

96
Q

quiz question

The emergent properties of water we have discussed (high specific heat, high heat of vaporization, ect..) are most directly the result of __________.

A

hydrogen bonding

97
Q

Following a _____________ reaction, a water molecule is produced.

A

Dehydration

98
Q

Hydrocarbons, molecules that are primarily C-H bonds, are ________.

A

Non-polar

99
Q

Polypeptide polymers are made up of ______ monomers.

A

amino acids

100
Q

___________ bonds result from sharing one or more electrons.

A

Covalent

101
Q

Due to hydrogen bonding, solid water is less dense than liquid water

A

True

102
Q

Nucleic Acid polymers are made up of ____________ monomers.

A

nucleotide

103
Q

An atom with 8 protons, 7 electrons and 8 neutrons is positively charged.

A

True

104
Q

Ribosomes are the site of _________________ synthesis.

A

protein

105
Q

Both plant and animal cells have mitochondria.

A

True

106
Q

Saturated fatty acids are more likely to be solid at room temperature

A

True

107
Q

β-pleated sheets form as part of a protein’s___________ structure.

A

Secondary

108
Q

The _____________ determines the unique chemical properties of an amino acid.

A

side-chain (R group)

109
Q

Solutes move from ________________ to __________________ concentration.

A

high; low

110
Q

The rough endoplasmic reticulum is so named due to the fact that _________, are embedded in the membrane

A

Ribosomes

General Biology 1 (13 decks)

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