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Biology 1113 > Midterm 2 Lecture Slides > Flashcards

Midterm 2 Lecture Slides Flashcards

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1
Q

Energy flows into an ecosystem as _____ and leaves as ____.

A

sunlight…heat

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2
Q

___ drives cellular work

A

ATP

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3
Q

About _____% of food ends up as ATP

A

30-35%

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4
Q

The energy stored in organic molecules of food ultimately comes from ____

A

the sun

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5
Q

Why do organic compounds possess potential energy?

A

the arrangement of electrons in the bonds

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6
Q

Aerobic respiration

A

harvests chemical energy in presence of O2

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7
Q

General Example Reaction

A

glucose+oxygen -> carbon dioxide + energy (ATP+heat)

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8
Q

Fermentation

A

a partial degradation of sugars that occurs without O2

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9
Q

Anaerobic respiration

A

similar to aerobic respiration, use substances other than O2 as an electron acceptor (like sulfate)

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10
Q

What releases energy stored in organic molecules?

A

the transfer of electrons

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11
Q

redox reactions

A

chemical reactions that transfer electrons between reactants

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12
Q

Oxidation

A

a substance loses electrons (oxidized)

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13
Q

Reduction

A

a substance gains electrons (reduced)

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14
Q

T/F: All redox reactions transfer electrons.

A

FALSE: Some just change the electron sharing in covalent bonds (closer to electronegative atom)

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15
Q

cellular respiration

A

the fuel (such as glucose) is oxidized and O2 is reduced

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16
Q

Electrons from organiz compounds are usually first transferred to _____

A

NAD+

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17
Q

NAD+ carries…

A

…high energy electrons and H

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18
Q

NADH passes the electrons to the _____

A

electron transport chain

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19
Q

The Stages of Cellular Respiration

A

1) glycolysis 2) the citric acid cycle 3) oxidative phosphorylation

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20
Q

Glycolysis

A

“sugar splitting” (into two molecules of pyruvate) / occurs in the cytoplasm in 2 phases : Energy investment and Energy payoff / produces 2 ATP and 2 NADH

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21
Q

Does glycolysis occur without O2?

A

Yes, it can occur whether or not O2 is present.

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22
Q

Oxidation of Pyruvate to Acetyl CoA

A

In the presence of O2, pyruvate can enter the mitochondrion (in euk cells) -> must be converted to acetyl CoA before Citric Acid Cycle / CO2 is releases and 1 molecule of NADH is formed for each pyruvate

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23
Q

The citric acid cycle (Krebs Cycle)

A

completes the breakdown of glucose and pyruvate to CO2 / generates: 1 ATP, 3 NADH, and 1 FADH2 per turn / acetyl joins cycle by combining with oxaloacetate (forms citrate) / 7 steps to decompose citrate back to oxaloacetate

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24
Q

In the Krebs Cycle, which products relay electrons extracted from food to the electron transport chain?

A

In the Krebs cycle, 3 NADH and 1 FADH2 do this

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25
Q

How many ATP molecules are generated by glycolysis and the citric acid cycle together?

A

4 ATP by substrate-level phosphorylation

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26
Q

What are the electrons being carried by NADH and FADH2 going to be used for?

A

to generate an electrochemical/concentration gradient

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27
Q

Oxidative phosphorylation

A

accounts for most of ATP synthesis / 2 electron carriers NADH and FADH2 donate electrons to the electron transport chain to power OP / in the cristae of the mitochondrion / mostly proteins in multiprotein complexes

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28
Q

In oxidative phosphorylation, how many proteins are in the chain?

A

I, II, III, IV (so 4)

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29
Q

How does redox play a role in the electron transport chain in oxidative phosphorylation?

A

The electron carriers become reduced as they receive an electron and oxidized as they pass it down to their more electronegative neighbor.

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30
Q

Electron carriers get ____ from ____ and pass it along until it finally becomes ____

A

e- …. NADH … O2

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31
Q

The pathway of electrons is a ______ process.

A

spontaneous

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32
Q

Electrons ___ in free energy as they go down the chain

A

drop

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33
Q

At the end of the chain in oxidative phosphorylation, what happens?

A

the electrons are passed to O2 and form H2O

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34
Q

Chemiosmosis

A

the use of energy in a H+ gradient to drive cellular work

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35
Q

ATP synthase

A

H+ moving back across the membrane, passing through the protein complex / uses the exergonic flow of H+ to drive phosphorylation of ADP forming ATP

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36
Q

Electron transfer in the electron transport chain causes proteins to _____

A

pump H+ from the mitochondrial matrix to the inermembrane space (then ATP synthase happens)

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37
Q

proton-motive force

A

the H+ gradient

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38
Q

During cellular respiration, most energy flows in the sequence:

A

glucose -> NADH -> electron transport chain -> proton-motive force -> ATP

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39
Q

How much ATP is made during cellular respiration per glucose molecule?

A

32 ATP

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40
Q

fermentation

A

substrate-level phosphorylation instead of the electron transport chain
happens when there is not O2 in conjunction with glycolysis

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41
Q

How much ATP is produced during fermentation per glucose molecule?

A

2 ATP

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42
Q

Two common types of fermentation:

A
  1. alcohol fermentation

2. lactic acid fermentation

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43
Q

alcohol fermentation

A

pyruvate is converted to ethanol in 2 steps:

  1. releases CO2
  2. produces ethanol
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44
Q

lactic acid fermentation

A

pyruvate is reduced by NADH / end product = lactate / no CO2 / human cells use when O2 is scarce

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45
Q

What are the only elements absolutely needed for energy?

A

C-H

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46
Q

Proteins are made of

A

amino acids

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47
Q

Glycolysis accepts a wide range of _____

A

carbohydrates

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48
Q

The most energy is in ____

A

lipids

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49
Q

What is necessary for proteins to be used in glycolysis?

A

The proteins must be broken into amino acids and then the amino groups must be removed.

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50
Q

Fats are digested to _______ and ________

A

glycerol (glycolysis) and fatty acids (acetyl CoA)

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51
Q

How are fatty acids broken down?

A

beta oxidation

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52
Q

_______ is the most common mechanism for metabolic control.

A

Feedback inhibition

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53
Q

If ATP concentration begins to drop, respiration _______

A

speeds up

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54
Q

Autotrophs

A

sustain themselves without eating anything derived from other organisms

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55
Q

Autotrophs are the ____ of the biosphere

A

producers

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56
Q

What does photosynthesis occur in? (4)

A
  1. plants
  2. algae
  3. other unicellular eukaryotes
  4. some prokaryotes
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57
Q

Heterotrophs

A

obtain their organic material from other organisms

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58
Q

Heterotrophs are the ______ of the biosphere.

A

consumers

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59
Q

If a heterotroph consumes the remains of dead organisms, it is called a _______

A

decomposer

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60
Q

How does CO2 enter and O2 exit the leaf?

A

stomata

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61
Q

Where are chloroplasts found?

A

mainly in the cells of the mesophyll

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62
Q

Where is chlorophyll found?

A

in the thylakoid membrane

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63
Q

What gives plants their green color?

A

chlorophyll

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64
Q

Why is photosynthesis the opposite of respiration?

A

it reverses the direction of electron flow

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65
Q

Photosynthesis is ____

A

a redox reaction in which H2O is oxidized and CO2 is reduced

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66
Q

What is oxidized in photosynthesis?

A

H2O

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67
Q

What is reduced in photosynthesis?

A

CO2

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68
Q

Is photosynthesis endergonic or exergonic?

A

endergonic -> the energy boost is provided by light

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69
Q

True or false: Photosynthesis consists of light reactions.

A

True

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70
Q

What are the steps in photosynthesis?

A

Split H2O
Release O2
Reduce the electron acceptor NADP+ to NADPH
Generate ATP from ADP by photophosphorylation

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71
Q

What does the Calvin cycle do and where is it located?

A

The Calvin cycle (in the stroma) forms sugar from CO2, using ATP and NADPH

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72
Q

Does the dark reaction happen only at night?

A

No, it happens all the time; it just does not require the light.

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73
Q

The distance between two peaks of light’s rhythmic waves

A

wavelengths

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74
Q

the discrete particles in light

A

photons

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75
Q

Each photon has a ____ quantity of energy.

A

fixed

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76
Q

Pigments

A

substances that absorb visible light

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77
Q

Wavelengths that are not absorbed are

A

reflected or transmitted

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78
Q

Chlorophyll ______ and _______ green light

A

reflects and transmits

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79
Q

Chlorophyll a

A

main photosynthetic pigment

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80
Q

Chlorophyll b and carotenoids

A

broaden the spectrum used for photosynthesis

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81
Q

absorption spectrum

A

a graph plotting a pigment’s light absorption versus wavelength

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82
Q

action spectrum

A

profiles the relative effectiveness of different wavelengths of radiation in driving a process

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83
Q

When a pigment absorbs light…

A

…it goes from a ground state to an unstable excited state

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84
Q

Photons are given off when

A

an excited electron falls back to ground state (fluorescence)

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85
Q

If illuminated, an isolated solution of chlorophyll will

A

fluoresce, giving off light and heat.

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86
Q

Photosystems

A

complexes of chlorophyll and proteins in the thylakoid membrane

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87
Q

light-harvesting complexes

A

consists of various pigment molecules bound to proteins; transfer the energy of photons to the reaction center

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88
Q

reaction-center complexes

A

special pair of chlorophyll a in the reaction center uses the energy from light not only to boost one of their electrons to a higher energy level, but also transfer it to a different molecule

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89
Q

primary electron acceptor

A

in the reaction center accepts excited electrons and is reduced as a result

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90
Q

Light Reaction - Linear Electron Flow

A
  1. A photon hits a pigment and its energy is passed among pigment molecules until it excites P680
  2. An excited electron from P680 is transferred to the primary electron acceptor (we now call is P680)+
  3. H2O is split by enzymes, and the electrons are transferred from the hydrogen atoms to P680+, thus reducing it to P680 (O2 released)
  4. Each electron “falls” down an electron transport chain from the primary electron acceptor of PS II to PS I
  5. Energy released by the fall drives the creation of a proton gradient across the thylakoid membrane
  6. In PS I, transferred light energy excites P700, which loses an electron to a primary electron acceptor
    -P700+ accepts an electron passed down from PS II via
    the electron transport chain
  7. Each electron “falls” down an electron transport chain from the primary electron acceptor of PS I to the protein ferredoxin (Fd)
  8. The electrons are then transferred to NADP+ and reduce it to NADPH
    -The electrons of NADPH are available for the reactions of the Calvin cycle
    • This process also removes an H+ from the stroma
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91
Q

strongest known oxidizing agent

A

P680+

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92
Q

In a light reaction, what drives ATP synthesis?

A

diffusion of H+ (protons) across the membrane

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93
Q

What “fills the hole” in PSII?

A

H2O

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94
Q

What “fills the hole” in PSI?

A

e-

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95
Q

Chloroplasts and mitochondria generate ATP by _____

A

chemiosmosis

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96
Q

Mitochondria use _____ for chemiosmosis

A

food

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97
Q

Chloroplasts use _____ for chemiosmosis

A

light

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98
Q

In mitochondria, ____ are pumped into the intermembrane space and drive _____ synthesis as they diffuse back into the mitochondrial matrix

A

protons; ATP

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99
Q

In chloroplasts, ____ are pumped into the thylakoid space and drive ______ synthesis as they diffuse back into the stroma.

A

protons; ATP

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100
Q

Calvin cycle

A
  1. builds sugar from smaller molecules by using ATP and the reducing power of electrons carried by NADPH
  2. Carbon enters the cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phosphate (needs 3 times cycle)
  3. for 1G3P cycle, cycle uses 9 ATP and 6 NADPH
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101
Q

How many G3P do you need to make glucose?

A

2

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102
Q

3 phases of Calvin cycle

A
  1. carbon fixation (rubisco)
  2. reduction
  3. regeneration of the CO2 acceptor
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103
Q

What best distinguishes living things from non-living?

A

The ability to produce more of their own kind

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104
Q

Cell cycle

A

the life of a cell from formation to its own division

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105
Q

Reproducing

A

when prokarytic cell and unicellular eukaryotic organism divides

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106
Q

Multicellular eukaryotes depend on cell division for

A

development from a fertilized cell
growth
repair

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107
Q

Types of cell division

A
  1. cell division which results in daughter cells with identical genetic information:
    binary fission
    mitosis
  2. cell division which yields nonidentical daughter cells that have half as many chromosomes as the parent cell
    meiosis
108
Q

Binary fission

A 
reproduction of bacteria and archaea
chromosomes replicates (beginning at the origin of replication)
plasma membrane pinches inward, dividing cell into 2
109
Q

Genome

A

all of the DNA in a cell

110
Q

Somatic cells

A

non reproductive

have two sets of chromosomes

111
Q

gametes

A

reproductive cells

have half as many chromosomes as somatic cells

112
Q

DNA molecules packaged into

A

chromosomes

113
Q

In chromosomes, DNA is associated with ____

A

proteins

114
Q

chromatin

A

a complex of DNA and protein that condenses during cell division

115
Q

each duplicated chromosome has two ____ ____ (joined copies of the original chromosome

A

sister chromatids

116
Q

centromere

A

the narrow “waist” of the duplicated chromosome (where the 2 sister chromatids are the most closely attached

117
Q

sister chromatids are attached along their lengths by

A

proteins cohesins

118
Q

The cell cycle consists of

A 
Interphase (90% - cell growth and copying of chromosomes in preparation for cell division)
    G1 phase
   S phase
   G2 phase
Mitotic (M) phase (cell division
   Mitosis (division of nucleus
   cytokinesis (division of cytoplasm)
119
Q

Mitosis

A 
Prophase
Prometaphase
Metaphase
Anaphase
Telophase and Cytokinesis
120
Q

Just before Mitsosis

A

Chromosomes duplicated during S phase
Chromosomes have not yet condensed
2 centrosomes have formed
nuclear envelope encloses the nucleus

121
Q

Prophase

A

Chromosomes begin to condense by looping
nucleoli disappeared
mitotic spindle begins to form

122
Q

Prometaphase

A

nuclear envelope fragmented (starte to have DNA free in cytoplasm)
chromosomes have become even more condensed
some of the microtubules of mitotic spindle attach to kinetochores

123
Q

kinetochores

A

protein complexes associated with centromeres

124
Q

Metaphase

A

chromosomes have all arrived at the metaphase plate

microtubules organize chromosomes in center of cell (caused by counteracting polar forces)

125
Q

Anaphase

A

begins when the cohesin proteins are cleaved
allows 2 sister chromatids of each pari to part suddenly (now 2 separate chromosomes)
now 2 daughter chromosomes begin moving toward opposite ends as their kinetochore microtubules shorten
cell elongated as nonkinetochore microtubules lengthen

126
Q

telophase/cytokinesis

A

2 daughter nuclei reform with new nuclear envelopes
chromosomes become less condensed
microtubules will disappear
cell is longer and split begins

127
Q

mitotic spindle

A

a structure made of microtubules that controls chromosome movement during mitosis

128
Q

In animal cells, the spindle includes ____ ____ ____

A

the centrosomes, the spindle microtubules, and the asters

129
Q

centrosome

A

microtubule organizing center

130
Q

aster

A

a radial array of short microtubules

131
Q

separase

A

cleaves the cohesins between sister chromatids in anaphase

132
Q

What elongates the cell?

A

Nonkinetochore microtubules from opposite poles overlapping and pushing against each other

133
Q

In animal cells, cytokinesis occurs by a process known as _____, forming a ____ ____

A

cleavage; cleavage furrow

134
Q

In plant cells, a ___ ____ forms during cytokinesis

A

cell plate

135
Q

Cell cycle control system

A

directs sequential events of cell cycle / has checkpoints [ places where cell cycle stops until given the “go ahead”]

136
Q

What can give a signal for the cell cycle control system?

A

cellular surveillance mechanisms within the cell

137
Q

Thre important checkpoints

A

G1, G2, M

138
Q

most important checkpoint

A

G1

139
Q

If it does not receive the signal at G1, a cell will enter ____

A

G0, a nondividing state

140
Q

Cells will not begin anaphase until

A

all chromosomes are properly attached to the spindle at the metaphase plate (ensures that daughter cells have the correct number of chromosomes) M checkpoint

141
Q

2 types of regulatory proteins involved in cell cycle control:

A

cyclins and cyclin-dependant kinases (Cdks)

142
Q

The activity of a Cdk rises and falls with

A

changes in concentration of its cyclin partner

143
Q

MPF

A

(maturation-promoting factor) is a cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase

144
Q

growth factors

A

released by certain cells and stimulate other cells to divide

145
Q

2 mechanisms which regulate optimal density of cells:

A
  1. density-dependent inhibition (less than a single layer)

2. anchorage dependence (need surface)

146
Q

If cells are not regulated by the 2 mechanisms for optimal density than they are

A

cancerous

147
Q

A normal cell is converted to a cancerous cell by a process called ____

A

transformation

148
Q

malignant tumor

A

invades surrounding tissues and can metastasize

149
Q

metastasize

A

exporting cancer cells to other parts of the body

150
Q

Meiosis

A

how chromosomes pass from parents to offspring in sexually reproducing organisms

151
Q

asexual reproduction

A

a single individual passes all of its genes ot its offspring without the fusion of gametes

152
Q

clone

A

a group of genetically identical individuals from the same parent (MITOSIS)

153
Q

sexual reproduction

A

2 parents give rise to offspring that have unique combinations of genes inherited from the 2 parents

154
Q

gametes

A

reproductive cells (sperm and eggs)

155
Q

What produces gametes?

A

Meiosis

156
Q

Why is sexual reproduction so common?

A

Sexual reproduction produces genetic diversity. (inc chance of some offspring surviving in changing environments)

157
Q

karyotype

A

ordered display of chromosomes from a cell

158
Q

human somatic cells have ____ chromosomes total

A

46 (23 pairs)

159
Q

The 2 chromosomes in each pari are called

A

homologous chromosomes (homologs)

160
Q

T/F: Chromosomes in a homologous pair are the same length and shape and carry genes controlling the same inherited characters

A

True

161
Q

autosomes

A

same for both sexes (22 pairs)

162
Q

Sex chromosomes

A

denoted by a letter (XX = female and XY = male)

163
Q

Each replicated chromosome consists of _________

A

2 identical sister chromatids

164
Q

The chromatids of 2 homologous chromosomes are called ____ chromatids

A

nonsister

165
Q

diploid cell

A

2 sets of chromosomes

166
Q

haploid

A

contains a single set of chromosomes (gametes)

167
Q

life cycle

A

generation-to-generation sequence of stages in the reproductive history of an organism

168
Q

meiosis

A

produce haploid cells

169
Q

fertilization

A

union of haploid cells

170
Q

zygote

A

fertilized egg (diploid - one set of chromosomes from each parent)

171
Q

Some algae can include both a diploid and haploid ____

A

multicellular stage

172
Q

Like mitosis, meiosis is preceded by the ______ of chromosomes in _____

A

replication; interphase

173
Q

Meiosis’s 2 consecutive cell divisions

A

Meiosis I

Meiosis II

174
Q

2 cell divisions result in ___ daughter cells

A

4

175
Q

Each daughter cell has ______ as many chromosomes as the parent cell

A

half

176
Q

Meiosis I

A

Prophase I
Metaphase I
Anaphase I
Telophase I and cytokinesis

[Meiosis I: Separates homologous chromosomes]

177
Q

Prophase I

A

each chromosome pairs wit its homolog and crossing over occurs
The DNA molecules of non-sister chromatids are broken and then rejoined to each other
X-shaped regions called chiasmata are sites of crossover

178
Q

chiasmata

A

sites of crossover

179
Q

Metaphase I

A

pairs of homologs line up at the metaphase plate

microtubules from one pole are attached to the kinetochore of one chromosome (both sister chromatids) of each tetrad

180
Q

Anaphase I

A

pairs of homologous chromosomes separate
one chromosome of each pari moves toward opposite poles, guided by the spindle apparatus
sister chromatids remain attached at the centromere and move as one unit toward the pole

181
Q

Telophase I and Cytokinesis

A

each half of the cell has a haploid set of chromosomes (still 2 sister chromatids)
cytokinesis usually occurs simultaneously (forming 2 haploid daughter cells)

182
Q

Meiosis II

A

Prophase II
Metaphase II
Anaphase II
Telophase II and cytokinesis

separates siter chromatids

183
Q

Prophase II

A

a spindle apparatus forms

In late prophase II, chromosomes (each still composed of 2 chromatids) moved toward the metaphase plate

184
Q

Metaphase II

A

the sister chromatids are arranged at the metaphase plate
because of crossing over in meiosis I THE TWO SISTER CHROMATIDS ARE NO LONGER GENETICALLY IDENTICAL
the kinetochores of sister chromatids attach to microtubules extending from opposite poles

185
Q

Anaphase II

A

the sister chromatids separate

now move as 2 newly individual chromosomes toward opposite poles

186
Q

Telophase II and Cytokinesis

A

arrive at the opposite poles
nuclei form, and chromosomes condensing
cytokinesis separates the cytoplasm
at the end: there are 4 daughter cells (each with a haploid set of unreplicated chromosomes)

EACH DAUGHTER CELL IS GENETICALLY DISTINCT FROM THE OTHERS AND FROMT HE PARENT CELL

187
Q

The original source of genetic diversity

A

mutations

188
Q

alleles

A

different versions of genes created by mutations

189
Q

Cause of genetic variation

A

reshuffling of alleles during sexual reproduction

190
Q

Three mechanisms of reshuffling

A

independent assortment of chromosomes
crossing over
random fertilization

191
Q

Independent Assortment of Chromosomes

A

homologs orient randomly at metaphase I of meiosis(number of possible combos is 2^n)

192
Q

Crossing Over

A 
recombinant chromosomes (combine DNA inherited from each parent)
1:3 crossover event per chromosohome
193
Q

synaptonemal complex

A

zipper-like structure that holds the homologs together tightly

194
Q

Random fertilization

A

any sperm can join with any egg

195
Q

Mendel

A

Austrian monk - discovered the basic principles of heredity by breeding garden peas
“Particulate” theory of inheritance - the idea that parents pass on discrete heritable units (genes)

196
Q

Advantages of using peas:

A

Short generation time
Large number of offspring
Mating could be controlled
Plants could be allowed to self-pollinate or could be cross pollinated

197
Q

character

A

a heritable feature that varies among individuals

198
Q

trait

A

each variant for a character

199
Q

heritable factor

A

gene

200
Q

true-breeding

A

produce offspring of the same variety when they self-pollinate

201
Q

hybridization

A

mating 2 contrasting, true-breeding varieties

202
Q

P generation

A

true-breeding plants

203
Q

F1 generation

A

the hybrid offspring of the P generation

204
Q

What theory did Mendel disprove?

A

The blending theory (bc he got the same results no matter which way he crossed them)

205
Q

F2 generation

A

F1 generation self-pollinated or cross-pollinates with other F1

206
Q

F2 generation in Mendel’s flowers

A

3:1 purple to white

207
Q

Mendel’s Model: 1st Concept

A

alternative versions of genes account for variation in inherited characters (alleles)

208
Q

Mendel’s Model: 2nd Concept

A

for each character , an organism inherits 2 alleles, one from each parent (meiosis)

209
Q

homozygous

A

2 identical alleles for a character

210
Q

heterozygous

A

two different alleles for a gene

211
Q

Mendel’s Model: 3rd Concept

A

if the 2 alleles at a locus differ, then 1 (the dominant allele) determines the organism’s appearance, and the other (the recessive allele) has no noticeable effect

212
Q

phenotype

A

physical appearance

213
Q

genotype

A

genetic makeup

214
Q

Mendel’s Model: 4th Concept (The Law of Segregation)

A

the 2 alleles for a heritable character separate/segregate during gamete formation and end up in different gametes
(an egg or sperm gets only one of the 2 alleles that are present in the organism)

215
Q

Punnett square

A

possible combinations of sperm and egg

216
Q

The Law of Independent Assortment

A

Each pair of alleles segregates independently of each other pair of alleles during gamete formation

[crossing 2 true-breeding parents differing in 2 characters produces dihybrids in the F1 generation (heterozygous for both characters)
A dihybrid cross (a cross between F1 dihybrids, can determine whether 2 characters are transmitted to offspring as a package or independently]

applies only to genes on different, nonhomologous chromosomes or those far apart on the same chromosome

217
Q

monohybrid cross

A

crossing monohybrids (heterozygous for one character)

218
Q

t/f: Genes located near each other on the same chromosome tend to be inherited together

A

True

219
Q

Multiplication rule

A

the probability that 2 or more independent events will occur together is the product of their individual probabilities

220
Q

addition rule

A

the probability that any one of two or more exclusive events will occur is calculated by adding together their individual properties

221
Q

multi-character cross

A

uses rules of multiplication to consider 2 Punnet squares of 4 instead of one of 16

222
Q

Situations in which inheritance of characters by a single gene may deviate from simple Mendelian patterns:

A

When alleles are not completely dominant or recessive
When a gene has multiple alleles
When a gene produces multiple phenotypes (pleiotropy)

223
Q

Complete dominance

A

occurs when phenotypes of the heterozygote and dominant homozygote are identical

224
Q

incomplete dominance

A

the phenotype of F1 hybrids is somewhere between the phenotypes of the 2 parental varieties

225
Q

Codominance

A

2 dominant alleles affect the phenotype in separate, distinguishable ways

226
Q

ABO blood(# phenotypes and # of alleles)

A

4 phenotypes, 3 alleles

227
Q

Inheritance of 2 or more genes may deviate from simple Mendelian patterns in

A

epistasis

polygenic inheritance

228
Q

Epistasis

A

a gene at one locus alters the phenotypic expression of a gene at a second locus

229
Q

quantitative characters

A

those that vary in the population along a continuum

230
Q

polygenic inheritance

A

an additive effect of 2 or more genes on a single phenotype (skin color and height)

231
Q

pedigrees

A

a family tree that describes the interrelationships of parents and children across generations

232
Q

Recessive disorders

A

show up only in individuals homozygous for the allele

233
Q

carriers

A

heterozygous individuals who carry the recessive allele

234
Q

Examples of recessive disorders

A

albinism, cystic fibrosis, sickle-cell

235
Q

Dominantly inherited disorders

A

dwarfism, Huntington’s disease

236
Q

Thomas Hunt Morgan

A

first solid evidence associating a specific gene with a specific chromosome (early 20th century)
fruit fly eye color [only 4 pair chromosome]
Determined that white eye must be on X-chromosome

237
Q

wild type

A

normal

238
Q

mutant

A

traits alternate to normal

239
Q

Sex chromosomes in mammals

A

big X and smaller Y

240
Q

Why do X and Y behave like homologues in men?

A

short segments at the end of Y are homologous with X

241
Q

Does X have genes unrelated to sex?

A

Yes, X has many genes unrelated to sex, but Y does not

242
Q

What is responsible for the development of the testes in the embryo?

A

SRY (sex-determining region on the Y) gene on the Y chromosome
6th week

243
Q

sex-linked gene

A

located on either sex chromosome

244
Q

Y-linked genes

A

genes on the Y chromosome (few)

245
Q

X-linked genes

A

genes on the X chromosome (follow specific patterns of inheritance)

246
Q

For a recessive X-linked trait to be expressed

A

A female needs 2 copies of the allele (homo)

A male needs only one copy of the allele (hetero)

247
Q

Some disorders caused by recessive alleles on the X chromosome in humans

A

color blindness

hemophilia

248
Q

X-linked disorders are more common in ______

A

men

249
Q

If a condition/disease is recessive, then _______

A

heterozygous females will not have the problem

250
Q

What happens to the extra X in a woman?

A

It condenses to a Barr body

if heterozygous for a gene on the X, then mosaic

251
Q

Mendel’s Law

A

each pair of alleles segregates independently of each other pair of alleles during gamete formation

252
Q

parental types

A

offspring type matches parents

253
Q

recombinant type

A

offspring is a new combination of traits

254
Q

Any 2 genes on different chromosomes assorting independently have a ____% frequency of recombination

A

50

255
Q

linked genes

A

genes located on the same chromosome that tend to be inherited together

256
Q

Recombinant inconsistencies caused by

A

crossing over of homologous chromosomes

257
Q

linkage map

A

a genetic map of a chromosome based on recombination frequencies (map unit = 1%)

258
Q

Recombination frequencies are higher if

A

the number is higher (the genes are far away) [most 50%]

259
Q

What is the source of all new alleles?

A

Random mutations

260
Q

nondisjunction

A

pairs of homologous chromosomes or sister chromatids do not separate normally during Meiosis I or II

[one gamete receives 2 of the same type of chromosome, and another receives no copy - ANEUPLOIDY]

261
Q

aneuploidy

A

an unusual amount of chromosomes

262
Q

Can live with nondisjunction. Results in:

A

downs, klinefelter, turner

263
Q

2 normal exceptions to Mendelian

A

genomic imprinting

inheritance of organelle genes

264
Q

extranuclear genes are inherited _______ because the zygote’s cytoplasm comes from the ________

A

maternally; egg

265
Q

genomic imprinting

A

silencing certain genes depending on which parent passed them on
result of the methylation of cysteine nucleotides
Most are critical for embryonic development.

Biology 1113 (7 decks)

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