Unit 4 Exam Flashcards
1
Q
DNA replication is a semiconservative process
A
old DNA is strung in with new DNA
2
Q
binary fission
A
1 mother cells yields 2 daughter cells, that are genetically identical
- old DNA and new DNA move to opposite sides
- 2 nucleotoids are assembled
- septum is partitioned in the middle of 2 daughter cells (FtsZ facilitates)
- when septum is complete, cell pinches in two
3
Q
nucleosome
A
1 part of DNA around histone
4
Q
solenoid
A
bunch of nucleosomes
5
Q
organization of DNA
A
DNA -> nucleosome -> solenoid -> chromatin loop -> rosettes of chromatin loops -> mitotic chromosome
6
Q
n chromosome
A
haploid
7
Q
2n chromosome
A
diploid
8
Q
Xn chromosome
A
polyploid
9
Q
proteins that package DNA in Eubacteria
A
SMC proteins
10
Q
proteins assist packaging DNA in Archaea
A
histone proteins
11
Q
proteins that assist packaging DNA in eukaryotes
A
histone proteins
12
Q
karyotype
A
visual representation of all of an organism’s chromosomes
13
Q
loci
A
physical location of gene in DNA
14
Q
gene
A
a DNA sequence coding a specific trait
15
Q
homologous chromosomes
A
same genes at the same loci
16
Q
allele
A
alternate form of a gene
17
Q
sister chromatids
A
replicated copies, bound by cohesion proteins and kinetochores
18
Q
clonal
A
each cell produced by cell division is identical, bacterial cell division
19
Q
chromatin
A
complex of about 40% DNA and about 60% protein
20
Q
nucleosome
A
composed on DNA and histone proteins, gives a bead on a string appearance
21
Q
heterochromatin
A
inactive domains of chromatin
22
Q
euchromatin
A
active domains of chromatin
23
Q
2 phases of cell cycle
A
interphase and M phase
24
Q
3 phases of interphase
A
G1, S, G2
25
2 phases of M phase
mitosis and cytokinesis
26
G1 phase
gap phase 1, primary growth phase of the cell, longest phase
27
S phase
synthesis, phase in which cell synthesizes a replica of its DNA genome
28
G2 phase
gap phase 2, second growth phase, microtubules begin to reorganize to form a spindle, involves preparation for separation of the newly replicated genome
29
mitosis
essential step in the separation of the two daughter genomes
30
5 stages of mitosis
prophase, prometaphase, metaphase, anaphase, telophase
31
cytokinesis
phase of the cell cycle when the cytoplasm divides, creating two daughter cells
32
cytokinesis in animal cells vs plant cells
animal cells: cleavage furrow
plant cells: cell plate
33
G0 phase
sometimes done in G1 before DNA replication, resting state
34
centromere
point of constriction on the chromosome containing repeated DNA sequences that bind specific proteins
35
kinetochore
proteins making up a disk like structure on chromosome, functions as an attachment site for microtubules
36
prophase
begins when individual condensed chromosomes first become visible with the light microscope, formation of spindle apparatus, nuclear envelope breaks down, golgi and ER are dispersed
37
prometaphase
chromosomes attach to microtubules at kinetochores, chromosomes move to equator of cell
38
metaphase
all chromosomes are aligned at equator of cell (metaphase plate), chromosomes are attached to opposite poles and under tension
39
anaphase
proteins holding centromeres are degraded, freeing individual chromosomes, chromosomes are pulled to opposite poles, spindles poles move apart
40
telophase
chromosomes are clustered at opposite poles and decondense, chromosomes turn into chromatin, nuclear envelopes reform, golgi and ER is reformed, spindle is disassembled
41
anaphase A
kinetochores are pulled by microtubules
42
anaphase B
poles move away from each other
43
G1/S checkpoint
primary point at which the cell decides whether or not to divide, nutritional state, growth factors, size of the cell
44
G2/M checkpoint
assesses the success of DNA replication, passage commits the cell to mitosis and cytokinesis, uses MPF
45
MPF
mitosis promoting factor, damage to DNA inhibits MPF
46
spindle checkpoint
assures all the chromosomes are attached to the spindle in prep for anaphase, uses APC
47
CdK
protein kinase that activates numerous cell proteins by phosphorylating them
48
APC
anaphase promoting complex, at spindle checkpoint, it senses everything in order and triggers anaphase
49
phenotype
physical makeup of an organism
50
genotype
genetic makeup of all organisms
51
homozygous cross
same copies of alleles
52
homozygous dominant
AA
53
homozygous recessive
aa
54
heterozygous cross
1 has dominant allele and 1 has recessive allele, Aa
55
pleiotropy
1 gene affects multiple traits
56
sex determination
inheritance pattern of sex chromosomes, determining XX vs XY
57
sex differentiation
developmental process to build the phenotype, driven by hormones to differentiate the sex, I.e., gonads, genitalia, body hair
58
AIS
androgen insensitivity syndrome
59
non disjunction
failure of chromosomes to properly separate in meiosis
60
trisomic
extra chromosome, ex. Down syndrome and Klinefelter syndrome
61
monosomic
missing 1 chromosome
62
XO-turner syndrome
only having X chromosome
63
sex linked traits
affect males more than females, more genes on X chromosome
64
autosomal
affected balance between genders
65
epigenetics
mechanisms that alter gene expression
66
gametes
egg and sperm, each contained two chromosomes
67
somatic cells
nonreproductive cells of embryos and mature individuals, containing 4 chromosomes
68
zygote
a single cell fused together from egg and sperm
69
syngamy
fertilization of egg and sperm to form a zygote
70
meiosis
produces haploid cells (egg or sperm) to form diploid cells, splitting the number of chromosomes before fusing them together to make sure they have the same number of chromosomes
71
sexual reproduction
alternation of meiosis and fertilization, child will inherit 23 chromosomes from mother and 23 chromosomes from father
72
germline cells
cells set aside for future animal reproduction, undergo meiosis to create haploid gametes
73
synapsis
when homologous chromosomes find each other and become closely associated, or pairing
74
synaptonemal complex
joining the paired homologs, consists of a central element connected by filaments to two sets of lateral elements that interact with the homolog
75
crossing over
process allows the homologs to exchange chromosomal arms, producing genetic recombination (humans typically have 2-3)
76
recombinants
chromosomes resulting from crossing over
77
chiasmata
sites of crossing over
78
main distinction of meiosis from mitosis
2 divisions with 1 round of DNA replication, pairing of homologous chromosomes
79
independent assortment
in meiosis I, pole may either receive the maternal or paternal homolog from any chromosome pair
80
tetrad
2 homologous chromosomes paired next to each other
81
Mendel's P-generation
establish true breeding parent lines through self fertilization
82
Mendel's F1 generation
perform reciprocal crosses
83
anthers
male part containing pollen to give rise to haploid spermc
84
carpel
female part containing ovules that give rise to haploid eggs
85
Mendel pea plant experiment
cut anthers off a purple plant and give it pollen (sperm) from a white plant
F1 generation of crossing just produced purple plants
F2 generation produced 3 purple (dominant) to 1 white (recessive)
86
genotype
total set of alleles that an individual contains
87
phenotype
physical appearance or other observable characteristics of that individual, result from an allele's expression
88
principle of segregation
2 alleles for a gene segregate during gamete formation and are rejoined at random, one from each parent, during fertilization
89
Punnett square
simple diagram visualizing the F2 possibilities
90
Principle of Independent Assortment
in a cross, the alleles of a gene segregate independently of other genes
91
testcross
an individual with unknown genotype is crossed with the homozygous recessive genotype
92
phenotypic plasticity
different phenotypes for the same genotype due to environmental conditions
93
polygenic inheritance
additive contributions to a phenotype by several genes giving a continuous distribution of a trait (ex. height), more than 1 gene mediates expression of a trait
94
heritability
variation in phenotype due to genetic factors
95
pleiotropic
an allele has more than one effect on the phenotype (ex. sickle cell anemia, cystic fibrosis), single gene may affect multiple traits
96
incomplete dominance
phenotype of heterozygote is intermediate between those of the two homozygotes
97
codominant
when each allele has its own affect on the phenotype, heterozygotes show aspects of both homozygotes (ex. AB blood type)
98
A blood type
add only galactosamine, iA dominant to i
99
B blood type
add only galactose, iB dominant to i
100
AB blood type
add both galactose and galactosamine, iAiB, codominant
101
O blood type
no sugar is added, ii allele, i is recessive
102
Drosophila study
found the gene for eye color to be sex linked in fruit flies
103
dosage compensation
one of the X chromosomes is inactivated in females, which ensures an equal level of expression from the sex chromosomes
104
barr body
inactivated X chromosome
105
genetic mosaics
their individual cells may express different alleles, depending on which chromosome is inactivated
106
genomic imprinting
phenotype of a specific allele is expressed when the allele comes from one parent but not from the other
107
epigenetic inheritance
epigenetic change is defined as a mitotically of meiotically stable change in gene function that does not involve a change in DNA sequence
108
linkage
do not undergo independent assortment, they are near each other so they will segregate
109
increase in distance between 2 genes on a chromosome....
more crossing over
110
recombination frequency
frequency of recombinant progeny in a testcross divided by total number of progeny
111
monosomy
loss of a single chromosome, most do not survive
112
trisomy
gain of a single chromosome, can lead to embryonic lethality
113
three point cross
to order genes, recombinant is in the middle, 2 parental on either side
114
pedigree
consistent graphical representation of matings/offsprings for a particular trait
square = male
circle = female
115
pedigree analysis
- is the trait dominant or recessive?
- is the trait sex linked or autosomal? (seen much more in males, then sex linked)
116
hemophilia
recessive disorder, expressed only when an individual does not possess any copy of the normal allele and so cannot produce one of the proteins necessary for clotting
117
amniocentesis
procedure that permits the prenatal diagnosis of many genetic disorders, takes hypodermic syringe to extract amniotic fluid for testing
118
CVS
chorionic villus sampling; injecting the syringe through the vaginal canal and extracting some of the placenta for testing
119
SRY gene
directs ovaries to become testes and clitoris to become penis
120
sequence of nitrogenous bases
go from 5' phosphate group to 3' hydroxy group
121
Chargaff's rules
proportion of A always equals T, and proportion of G always equals C
122
how many hydrogen bonds forming A-T base pair
2 hydrogen bonds, easier to open
123
how many hydrogen bonds forming G-C base pair
3 hydrogen bonds
124
oriC
origin of DNA replication in E coli
125
replicon
DNA controlled by an origin
125
terminus
where the DNA replication ends in E coli
126
DNA polymerase 1
acts on lagging strand
127
DNA polymerase 2
proofreading
128
DNA polymerase 3
main replicating enzyme
129
endonucleases
cut DNA internally
130
exonucleases
remove nucleotides from end of DNA
131
helicase
enzyme with DNA unwinding activity, requires ATP, forming single strands
132
supercoiling
unwinding of two strands, introduces torsional strain
133
topoisomerases
enzymes that can alter the topological state of DNA, ex. gyrase
134
gyrase
type of topoisomerase, goes before helicase to relieve torsional strain so polymerase can replicate new DNA
135
leading strand
strand synthesized in a continuous fashion from an initial primer
136
lagging strand
strand that is discontinuous
137
Okazaki fragments
DNA fragments synthesized on the lagging strand
138
replication fork
partial opening of a DNA helix to form 2 single strands, produces a forked structure
139
DNA ligase
seals the "nick," joining the Okazaki fragments into complete strands
140
primose
synthesizes RNA primers
