Midterm 2 Lecture Slides Flashcards
(265 cards)
1
Q
Energy flows into an ecosystem as _____ and leaves as ____.
A
sunlight…heat
2
Q
___ drives cellular work
A
ATP
3
Q
About _____% of food ends up as ATP
A
30-35%
4
Q
The energy stored in organic molecules of food ultimately comes from ____
A
the sun
5
Q
Why do organic compounds possess potential energy?
A
the arrangement of electrons in the bonds
6
Q
Aerobic respiration
A
harvests chemical energy in presence of O2
7
Q
General Example Reaction
A
glucose+oxygen -> carbon dioxide + energy (ATP+heat)
8
Q
Fermentation
A
a partial degradation of sugars that occurs without O2
9
Q
Anaerobic respiration
A
similar to aerobic respiration, use substances other than O2 as an electron acceptor (like sulfate)
10
Q
What releases energy stored in organic molecules?
A
the transfer of electrons
11
Q
redox reactions
A
chemical reactions that transfer electrons between reactants
12
Q
Oxidation
A
a substance loses electrons (oxidized)
13
Q
Reduction
A
a substance gains electrons (reduced)
14
Q
T/F: All redox reactions transfer electrons.
A
FALSE: Some just change the electron sharing in covalent bonds (closer to electronegative atom)
15
Q
cellular respiration
A
the fuel (such as glucose) is oxidized and O2 is reduced
16
Q
Electrons from organiz compounds are usually first transferred to _____
A
NAD+
17
Q
NAD+ carries…
A
…high energy electrons and H
18
Q
NADH passes the electrons to the _____
A
electron transport chain
19
Q
The Stages of Cellular Respiration
A
1) glycolysis 2) the citric acid cycle 3) oxidative phosphorylation
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
21
Q
Does glycolysis occur without O2?
A
Yes, it can occur whether or not O2 is present.
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
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
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
25
How many ATP molecules are generated by glycolysis and the citric acid cycle together?
4 ATP by substrate-level phosphorylation
26
What are the electrons being carried by NADH and FADH2 going to be used for?
to generate an electrochemical/concentration gradient
27
Oxidative phosphorylation
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
28
In oxidative phosphorylation, how many proteins are in the chain?
I, II, III, IV (so 4)
29
How does redox play a role in the electron transport chain in oxidative phosphorylation?
The electron carriers become reduced as they receive an electron and oxidized as they pass it down to their more electronegative neighbor.
30
Electron carriers get ____ from ____ and pass it along until it finally becomes ____
e- .... NADH ... O2
31
The pathway of electrons is a ______ process.
spontaneous
32
Electrons ___ in free energy as they go down the chain
drop
33
At the end of the chain in oxidative phosphorylation, what happens?
the electrons are passed to O2 and form H2O
34
Chemiosmosis
the use of energy in a H+ gradient to drive cellular work
35
ATP synthase
H+ moving back across the membrane, passing through the protein complex / uses the exergonic flow of H+ to drive phosphorylation of ADP forming ATP
36
Electron transfer in the electron transport chain causes proteins to _____
pump H+ from the mitochondrial matrix to the inermembrane space (then ATP synthase happens)
37
proton-motive force
the H+ gradient
38
During cellular respiration, most energy flows in the sequence:
glucose -> NADH -> electron transport chain -> proton-motive force -> ATP
39
How much ATP is made during cellular respiration per glucose molecule?
32 ATP
40
fermentation
substrate-level phosphorylation instead of the electron transport chain
happens when there is not O2 in conjunction with glycolysis
41
How much ATP is produced during fermentation per glucose molecule?
2 ATP
42
Two common types of fermentation:
1. alcohol fermentation
| 2. lactic acid fermentation
43
alcohol fermentation
pyruvate is converted to ethanol in 2 steps:
1. releases CO2
2. produces ethanol
44
lactic acid fermentation
pyruvate is reduced by NADH / end product = lactate / no CO2 / human cells use when O2 is scarce
45
What are the only elements absolutely needed for energy?
C-H
46
Proteins are made of
amino acids
47
Glycolysis accepts a wide range of _____
carbohydrates
48
The most energy is in ____
lipids
49
What is necessary for proteins to be used in glycolysis?
The proteins must be broken into amino acids and then the amino groups must be removed.
50
Fats are digested to _______ and ________
glycerol (glycolysis) and fatty acids (acetyl CoA)
51
How are fatty acids broken down?
beta oxidation
52
_______ is the most common mechanism for metabolic control.
Feedback inhibition
53
If ATP concentration begins to drop, respiration _______
speeds up
54
Autotrophs
sustain themselves without eating anything derived from other organisms
55
Autotrophs are the ____ of the biosphere
producers
56
What does photosynthesis occur in? (4)
1. plants
2. algae
3. other unicellular eukaryotes
4. some prokaryotes
57
Heterotrophs
obtain their organic material from other organisms
58
Heterotrophs are the ______ of the biosphere.
consumers
59
If a heterotroph consumes the remains of dead organisms, it is called a _______
decomposer
60
How does CO2 enter and O2 exit the leaf?
stomata
61
Where are chloroplasts found?
mainly in the cells of the mesophyll
62
Where is chlorophyll found?
in the thylakoid membrane
63
What gives plants their green color?
chlorophyll
64
Why is photosynthesis the opposite of respiration?
it reverses the direction of electron flow
65
Photosynthesis is ____
a redox reaction in which H2O is oxidized and CO2 is reduced
66
What is oxidized in photosynthesis?
H2O
67
What is reduced in photosynthesis?
CO2
68
Is photosynthesis endergonic or exergonic?
endergonic -> the energy boost is provided by light
69
True or false: Photosynthesis consists of light reactions.
True
70
What are the steps in photosynthesis?
Split H2O
Release O2
Reduce the electron acceptor NADP+ to NADPH
Generate ATP from ADP by photophosphorylation
71
What does the Calvin cycle do and where is it located?
The Calvin cycle (in the stroma) forms sugar from CO2, using ATP and NADPH
72
Does the dark reaction happen only at night?
No, it happens all the time; it just does not require the light.
73
The distance between two peaks of light's rhythmic waves
wavelengths
74
the discrete particles in light
photons
75
Each photon has a ____ quantity of energy.
fixed
76
Pigments
substances that absorb visible light
77
Wavelengths that are not absorbed are
reflected or transmitted
78
Chlorophyll ______ and _______ green light
reflects and transmits
79
Chlorophyll a
main photosynthetic pigment
80
Chlorophyll b and carotenoids
broaden the spectrum used for photosynthesis
81
absorption spectrum
a graph plotting a pigment's light absorption versus wavelength
82
action spectrum
profiles the relative effectiveness of different wavelengths of radiation in driving a process
83
When a pigment absorbs light...
...it goes from a ground state to an unstable excited state
84
Photons are given off when
an excited electron falls back to ground state (fluorescence)
85
If illuminated, an isolated solution of chlorophyll will
fluoresce, giving off light and heat.
86
Photosystems
complexes of chlorophyll and proteins in the thylakoid membrane
87
light-harvesting complexes
consists of various pigment molecules bound to proteins; transfer the energy of photons to the reaction center
88
reaction-center complexes
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
89
primary electron acceptor
in the reaction center accepts excited electrons and is reduced as a result
90
Light Reaction - Linear Electron Flow
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
91
strongest known oxidizing agent
P680+
92
In a light reaction, what drives ATP synthesis?
diffusion of H+ (protons) across the membrane
93
What "fills the hole" in PSII?
H2O
94
What "fills the hole" in PSI?
e-
95
Chloroplasts and mitochondria generate ATP by _____
chemiosmosis
96
Mitochondria use _____ for chemiosmosis
food
97
Chloroplasts use _____ for chemiosmosis
light
98
In mitochondria, ____ are pumped into the intermembrane space and drive _____ synthesis as they diffuse back into the mitochondrial matrix
protons; ATP
99
In chloroplasts, ____ are pumped into the thylakoid space and drive ______ synthesis as they diffuse back into the stroma.
protons; ATP
100
Calvin cycle
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
101
How many G3P do you need to make glucose?
2
102
3 phases of Calvin cycle
1. carbon fixation (rubisco)
2. reduction
3. regeneration of the CO2 acceptor
103
What best distinguishes living things from non-living?
The ability to produce more of their own kind
104
Cell cycle
the life of a cell from formation to its own division
105
Reproducing
when prokarytic cell and unicellular eukaryotic organism divides
106
Multicellular eukaryotes depend on cell division for
development from a fertilized cell
growth
repair
107
Types of cell division
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
Binary fission
```
reproduction of bacteria and archaea
chromosomes replicates (beginning at the origin of replication)
plasma membrane pinches inward, dividing cell into 2
```
109
Genome
all of the DNA in a cell
110
Somatic cells
non reproductive
| have two sets of chromosomes
111
gametes
reproductive cells
| have half as many chromosomes as somatic cells
112
DNA molecules packaged into
chromosomes
113
In chromosomes, DNA is associated with ____
proteins
114
chromatin
a complex of DNA and protein that condenses during cell division
115
each duplicated chromosome has two ____ ____ (joined copies of the original chromosome
sister chromatids
116
centromere
the narrow "waist" of the duplicated chromosome (where the 2 sister chromatids are the most closely attached
117
sister chromatids are attached along their lengths by
proteins cohesins
118
The cell cycle consists of
```
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
Mitosis
```
Prophase
Prometaphase
Metaphase
Anaphase
Telophase and Cytokinesis
```
120
Just before Mitsosis
Chromosomes duplicated during S phase
Chromosomes have not yet condensed
2 centrosomes have formed
nuclear envelope encloses the nucleus
121
Prophase
Chromosomes begin to condense by looping
nucleoli disappeared
mitotic spindle begins to form
122
Prometaphase
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
kinetochores
protein complexes associated with centromeres
124
Metaphase
chromosomes have all arrived at the metaphase plate
| microtubules organize chromosomes in center of cell (caused by counteracting polar forces)
125
Anaphase
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
telophase/cytokinesis
2 daughter nuclei reform with new nuclear envelopes
chromosomes become less condensed
microtubules will disappear
cell is longer and split begins
127
mitotic spindle
a structure made of microtubules that controls chromosome movement during mitosis
128
In animal cells, the spindle includes ____ ____ ____
the centrosomes, the spindle microtubules, and the asters
129
centrosome
microtubule organizing center
130
aster
a radial array of short microtubules
131
separase
cleaves the cohesins between sister chromatids in anaphase
132
What elongates the cell?
Nonkinetochore microtubules from opposite poles overlapping and pushing against each other
133
In animal cells, cytokinesis occurs by a process known as _____, forming a ____ ____
cleavage; cleavage furrow
134
In plant cells, a ___ ____ forms during cytokinesis
cell plate
135
Cell cycle control system
directs sequential events of cell cycle / has checkpoints [ places where cell cycle stops until given the "go ahead"]
136
What can give a signal for the cell cycle control system?
cellular surveillance mechanisms within the cell
137
Thre important checkpoints
G1, G2, M
138
most important checkpoint
G1
139
If it does not receive the signal at G1, a cell will enter ____
G0, a nondividing state
140
Cells will not begin anaphase until
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
2 types of regulatory proteins involved in cell cycle control:
cyclins and cyclin-dependant kinases (Cdks)
142
The activity of a Cdk rises and falls with
changes in concentration of its cyclin partner
143
MPF
(maturation-promoting factor) is a cyclin-Cdk complex that triggers a cell's passage past the G2 checkpoint into the M phase
144
growth factors
released by certain cells and stimulate other cells to divide
145
2 mechanisms which regulate optimal density of cells:
1. density-dependent inhibition (less than a single layer)
| 2. anchorage dependence (need surface)
146
If cells are not regulated by the 2 mechanisms for optimal density than they are
cancerous
147
A normal cell is converted to a cancerous cell by a process called ____
transformation
148
malignant tumor
invades surrounding tissues and can metastasize
149
metastasize
exporting cancer cells to other parts of the body
150
Meiosis
how chromosomes pass from parents to offspring in sexually reproducing organisms
151
asexual reproduction
a single individual passes all of its genes ot its offspring without the fusion of gametes
152
clone
a group of genetically identical individuals from the same parent (MITOSIS)
153
sexual reproduction
2 parents give rise to offspring that have unique combinations of genes inherited from the 2 parents
154
gametes
reproductive cells (sperm and eggs)
155
What produces gametes?
Meiosis
156
Why is sexual reproduction so common?
Sexual reproduction produces genetic diversity. (inc chance of some offspring surviving in changing environments)
157
karyotype
ordered display of chromosomes from a cell
158
human somatic cells have ____ chromosomes total
46 (23 pairs)
159
The 2 chromosomes in each pari are called
homologous chromosomes (homologs)
160
T/F: Chromosomes in a homologous pair are the same length and shape and carry genes controlling the same inherited characters
True
161
autosomes
same for both sexes (22 pairs)
162
Sex chromosomes
denoted by a letter (XX = female and XY = male)
163
Each replicated chromosome consists of _________
2 identical sister chromatids
164
The chromatids of 2 homologous chromosomes are called ____ chromatids
nonsister
165
diploid cell
2 sets of chromosomes
166
haploid
contains a single set of chromosomes (gametes)
167
life cycle
generation-to-generation sequence of stages in the reproductive history of an organism
168
meiosis
produce haploid cells
169
fertilization
union of haploid cells
170
zygote
fertilized egg (diploid - one set of chromosomes from each parent)
171
Some algae can include both a diploid and haploid ____
multicellular stage
172
Like mitosis, meiosis is preceded by the ______ of chromosomes in _____
replication; interphase
173
Meiosis's 2 consecutive cell divisions
Meiosis I
| Meiosis II
174
2 cell divisions result in ___ daughter cells
4
175
Each daughter cell has ______ as many chromosomes as the parent cell
half
176
Meiosis I
Prophase I
Metaphase I
Anaphase I
Telophase I and cytokinesis
[Meiosis I: Separates homologous chromosomes]
177
Prophase I
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
chiasmata
sites of crossover
179
Metaphase I
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
Anaphase I
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
Telophase I and Cytokinesis
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
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II and cytokinesis
separates siter chromatids
183
Prophase II
a spindle apparatus forms
| In late prophase II, chromosomes (each still composed of 2 chromatids) moved toward the metaphase plate
184
Metaphase II
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
Anaphase II
the sister chromatids separate
| now move as 2 newly individual chromosomes toward opposite poles
186
Telophase II and Cytokinesis
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
The original source of genetic diversity
mutations
188
alleles
different versions of genes created by mutations
189
Cause of genetic variation
reshuffling of alleles during sexual reproduction
190
Three mechanisms of reshuffling
independent assortment of chromosomes
crossing over
random fertilization
191
Independent Assortment of Chromosomes
homologs orient randomly at metaphase I of meiosis(number of possible combos is 2^n)
192
Crossing Over
```
recombinant chromosomes (combine DNA inherited from each parent)
1:3 crossover event per chromosohome
```
193
synaptonemal complex
zipper-like structure that holds the homologs together tightly
194
Random fertilization
any sperm can join with any egg
195
Mendel
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
Advantages of using peas:
Short generation time
Large number of offspring
Mating could be controlled
Plants could be allowed to self-pollinate or could be cross pollinated
197
character
a heritable feature that varies among individuals
198
trait
each variant for a character
199
heritable factor
gene
200
true-breeding
produce offspring of the same variety when they self-pollinate
201
hybridization
mating 2 contrasting, true-breeding varieties
202
P generation
true-breeding plants
203
F1 generation
the hybrid offspring of the P generation
204
What theory did Mendel disprove?
The blending theory (bc he got the same results no matter which way he crossed them)
205
F2 generation
F1 generation self-pollinated or cross-pollinates with other F1
206
F2 generation in Mendel's flowers
3:1 purple to white
207
Mendel's Model: 1st Concept
alternative versions of genes account for variation in inherited characters (alleles)
208
Mendel's Model: 2nd Concept
for each character , an organism inherits 2 alleles, one from each parent (meiosis)
209
homozygous
2 identical alleles for a character
210
heterozygous
two different alleles for a gene
211
Mendel's Model: 3rd Concept
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
phenotype
physical appearance
213
genotype
genetic makeup
214
Mendel's Model: 4th Concept (The Law of Segregation)
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
Punnett square
possible combinations of sperm and egg
216
The Law of Independent Assortment
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
monohybrid cross
crossing monohybrids (heterozygous for one character)
218
t/f: Genes located near each other on the same chromosome tend to be inherited together
True
219
Multiplication rule
the probability that 2 or more independent events will occur together is the product of their individual probabilities
220
addition rule
the probability that any one of two or more exclusive events will occur is calculated by adding together their individual properties
221
multi-character cross
uses rules of multiplication to consider 2 Punnet squares of 4 instead of one of 16
222
Situations in which inheritance of characters by a single gene may deviate from simple Mendelian patterns:
When alleles are not completely dominant or recessive
When a gene has multiple alleles
When a gene produces multiple phenotypes (pleiotropy)
223
Complete dominance
occurs when phenotypes of the heterozygote and dominant homozygote are identical
224
incomplete dominance
the phenotype of F1 hybrids is somewhere between the phenotypes of the 2 parental varieties
225
Codominance
2 dominant alleles affect the phenotype in separate, distinguishable ways
226
ABO blood(# phenotypes and # of alleles)
4 phenotypes, 3 alleles
227
Inheritance of 2 or more genes may deviate from simple Mendelian patterns in
epistasis
| polygenic inheritance
228
Epistasis
a gene at one locus alters the phenotypic expression of a gene at a second locus
229
quantitative characters
those that vary in the population along a continuum
230
polygenic inheritance
an additive effect of 2 or more genes on a single phenotype (skin color and height)
231
pedigrees
a family tree that describes the interrelationships of parents and children across generations
232
Recessive disorders
show up only in individuals homozygous for the allele
233
carriers
heterozygous individuals who carry the recessive allele
234
Examples of recessive disorders
albinism, cystic fibrosis, sickle-cell
235
Dominantly inherited disorders
dwarfism, Huntington's disease
236
Thomas Hunt Morgan
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
wild type
normal
238
mutant
traits alternate to normal
239
Sex chromosomes in mammals
big X and smaller Y
240
Why do X and Y behave like homologues in men?
short segments at the end of Y are homologous with X
241
Does X have genes unrelated to sex?
Yes, X has many genes unrelated to sex, but Y does not
242
What is responsible for the development of the testes in the embryo?
SRY (sex-determining region on the Y) gene on the Y chromosome
6th week
243
sex-linked gene
located on either sex chromosome
244
Y-linked genes
genes on the Y chromosome (few)
245
X-linked genes
genes on the X chromosome (follow specific patterns of inheritance)
246
For a recessive X-linked trait to be expressed
A female needs 2 copies of the allele (homo)
| A male needs only one copy of the allele (hetero)
247
Some disorders caused by recessive alleles on the X chromosome in humans
color blindness
| hemophilia
248
X-linked disorders are more common in ______
men
249
If a condition/disease is recessive, then _______
heterozygous females will not have the problem
250
What happens to the extra X in a woman?
It condenses to a Barr body
| if heterozygous for a gene on the X, then mosaic
251
Mendel's Law
each pair of alleles segregates independently of each other pair of alleles during gamete formation
252
parental types
offspring type matches parents
253
recombinant type
offspring is a new combination of traits
254
Any 2 genes on different chromosomes assorting independently have a ____% frequency of recombination
50
255
linked genes
genes located on the same chromosome that tend to be inherited together
256
Recombinant inconsistencies caused by
crossing over of homologous chromosomes
257
linkage map
a genetic map of a chromosome based on recombination frequencies (map unit = 1%)
258
Recombination frequencies are higher if
the number is higher (the genes are far away) [most 50%]
259
What is the source of all new alleles?
Random mutations
260
nondisjunction
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
aneuploidy
an unusual amount of chromosomes
262
Can live with nondisjunction. Results in:
downs, klinefelter, turner
263
2 normal exceptions to Mendelian
genomic imprinting
| inheritance of organelle genes
264
extranuclear genes are inherited _______ because the zygote's cytoplasm comes from the ________
maternally; egg
265
genomic imprinting
silencing certain genes depending on which parent passed them on
result of the methylation of cysteine nucleotides
Most are critical for embryonic development.
