Cell Cycle Flashcards
1
Q
cell cycle
A
- division of somatic cell into 2 daughter cells
- include: interphase & mitotic phase
2
Q
interphase occurences
A
- 3 phases: G1, S, G2
- chromosomes present as chromatin
- genes are transcribed to mRNA to make protein
3
Q
G1 phase
A
- last 8-10 hours
- growth and metabolism
- results: replicated chromosomes
4
Q
S phase
A
- last 6-8 hours
- DNA replicated + connected by centromere (sister chromatid)
- kinetochore proteins attach to centromere
5
Q
G2 phase
A
- last 4-6 hours
- enzymes and proteins are produced
- 2 sister chromatids attached at centromere
6
Q
mitosis
A
- 1 hour to complete
- growth and tissue repair
- involves: mitosis & cytokinesis
- results: 2 genetically identical daughter cells
7
Q
prophase
A
- chromatin is visible
- nuclear membrane & nucleoli disappear
- centrosomes go to opposite poles
- centromere have spindle fiber
- kinetochore attach to spindle microtubules
8
Q
metaphase
A
- sister chromatids lines in center of cell (metaphase plate)
- 46 chromosomes
9
Q
anaphase
A
- kinetochore fibers separate sister chromatids to pole
- cytokinesis begins
10
Q
telophase
A
- spindle break
- chromosomes uncoil > chromatin
- nuclear membrane & nucleoli appear
- results: 2 identical daughter cells
11
Q
meiosis
A
- sex cells
- 2n diploid to n haploid
- includes: meiosis I & meiosis II
12
Q
meiosis I
A
- separate homologous pairs
- diploid to haploid
13
Q
meiosis II
A
- separate sister chromatids
- result: 4 haploid gametes
- steps are the same as meiosis I
14
Q
prophase I
A
- synapsis
- tetrad: 4 sister chromatids
- crossing over (in synapsis)
15
Q
metaphase I
A
- tetrad align at plate
- microtubules attach to kinetochore
16
Q
anaphase I
A
- homologous pairs separate to poles
17
Q
telophase I
A
- each pole has haploid number chromosomes
18
Q
cytokinesis I
A
- overlaps telophase
- results: 2 haploid w/ 2 sister chromatids
19
Q
fertilization / development
A
haploid sperm + oocyte = diploid zygote
20
Q
pre-embryonic develoment
A
- first 2 weeks after fertilization
- zygote > embryo
cleavage division: dividing cell > morula (solid ball of cells)
21
Q
gestation
A
morula divides > blastocyst
- 5 days after fertilization
22
Q
blastocyst
A
- fluid filled cavity
- composed of:
trophoblast cell: surround blastocyst + provide nourishment (becomes chorion)
embryoblast: becomes embryo
23
Q
implantation
A
- attachment of blastocyst to endometrium
- 5-7 days post
- embryoblast > embryonic disk
disk consists of…
epiblast: rise to fetus
hypoblast: rise to yolk sac
24
Q
embryonic development
A
- 3rd-8th week post
- endoblast layer has ectoderm, mesoderm, endoderm
25
what happens at the 4th-8th week post??
- major organs develop
- heart beats
- brains begins too develop
- limb buds differenciate
26
ectoderm
form nervous system + epidermal layer
27
mesoderm
form muscle, bone, blood vessels, dermis
28
endoderm
form epithelial layer of digestive, respiratory, urinary, reproductive tract & associated glands
29
embryonic membranes consist of...
1) amnion
2) yolk sac
3) chorion
4) allantois
30
amnion
- from epiblast
| - filled cavity surrounding embryo (reduce disturbances)
31
yolk sac
- from hypoblast
| - produce early blood & germ cells
32
chorion
- from trophoblast cells
- fetal portion of placenta
- surrounds embryonic membranes
33
allantois
- pocketing of yolk sac
| - umbilical cord & urinary bladder
34
fetal development
- 9th-40th week
35
inheritance
- transfer of genetically determined characteristics
36
genetics
study of inheritance
37
genes
segment of DNA on chromosome to direct protein synthesis
38
chromosomes
DNA + histone proteins
39
alleles
same locus on chromosome
40
homozgous alleles
both gene copies encode same version of gene
41
heterozygous alleles
both gene copies encode diff. version of gene
42
dominant allele
fully exposed trait
43
recessive allele
can be hidden by dominant
44
genotype
genetic makeup of person
45
phenotype
how genotype is expressed
46
sex chromosomes: male & female
male: never homozygous (genotype depends on X carriers)
female: can be homo/hetero (X chromosomes carry same gene at same loci)
47
what is a punnett square?
predicts characteristic of offspring + probability of inheritance
48
what is autosomal inheritance?
genes located on chromosomes 1-22
