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Biology Honors > biology: cellular reproduction > Flashcards

biology: cellular reproduction Flashcards

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0
Q

what is in the nucleus

A

deoxyribonucleic acid
chromatin
chromosome
histones

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1
Q

why do cells divide?

A

need for large surface-volume ratio

limited capacity of nucleus

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2
Q

deoxyribonucleic acid function

A

DNA
provided information for determining characteristics
majority in nucleus

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3
Q

what is chromatin and where is it found

A

threadlike form of DNA

exists when cell is not dividing

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4
Q

at is a chromosome and where is it found in cell cycle?

A

condensed form of DNA
during cell division
allows movement without tangling or breaking

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5
Q

what is a histone and what do they do?

A

protein DNA wraps around
provide stability/ organization and compaction to fit in cell
creates a nucleosome

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6
Q

what about prokaryotes that do not have a nucleus?

A

single, circular DNA
“naked”- no histones to wrap around
no nucleus, DNA attaches to plasma membrane

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7
Q

chromatid

A

duplicated half of a chromosome

collectively identical halves called “sister chromosomes”

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8
Q

centromere

A

protein dish that attaches sister chromatids together

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9
Q

Sex chromosomes

A

chromosomes that determine sex
in humans 2 X= female
1 Y and 1 X= male

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10
Q

autosomes

A

all chromosomes except sex chromosomes
all sexually reproducing organisms have two copies of each
one from each parent

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11
Q

homologous chromosomes

A

two copies of each autosome

same size, shape, and genetic information

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12
Q

karyotype

A

picture of chromosome in dividing state

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13
Q

diploids

A

cells that have two homologies of each chromosome
represented as 2n
in humans found in every single cell except sperm or egg

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14
Q

haploid

A

cell that has one set of chromosomes, half of diploid
represented as n or 1n
in humans only in sperm or egg (23 chromosomes)

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15
Q

how do prokaryotes divide?

A

easy because theirs no nucleus
asexual
binary fission
division of one cell into two identical cells

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16
Q

what happens during binary fission? 5 steps

A
  1. DNA replicates
  2. New cell membrane grows between DNA
  3. Cell grows to twice its size
  4. Cell wall grows around new membrane
  5. Cell divides into two identical cells
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17
Q

how do eukaryotes divide?

A

more complicated due to nucleus

mitosis and meiosis and then cytokinesis

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18
Q

what is mitosis

A

division of one nucleus (2n) into two identical nuclei (2n)

used for all cells except sperm and egg

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19
Q

what is meiosis

A

division of one nucleus (2n) into two haploid nuclei (1n)

used for sperm and egg

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20
Q

what is cytokinesis

A

division of cytoplasm

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21
Q

wht is the cell cycle?

A

repeating set of events in the life of a cell

includes interphase, mitosis, and cytokinesis

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22
Q

what is interphase?

A

time when cell is not dividing
most time spent in this phase
DNA in chromatin form
three phases

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23
Q

G1 phase

A

first phase
longest phase
cell volume grows as it produces cell components

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24
S phase
second phase DNA replication occur 92 chromatids- two per chromosome
25
G2 phase
third and final phase | cell gets ready for mitosis/ cytokinesis
26
G0 phase
non-dividing state, most human cells | some cells never divide like muscle and nerve fiber
27
what triggers a cell to leave interphase and begin to divide?
regulated by proteins and feedback signal
28
cell growth (G1) checkpoint
cell healthy and suitable size- go to S phase | unfavorable conditions- stop and rest or go to G0
29
DNA synthesis G2 checkpoint
accurate DNA synthesis/ replication- go to M phase
30
Mitosis checkpoint
chromosomes lined up correctly- finish mitosis
31
what is cell senescence
limited number of times a cell divides
32
what happens if cell loses control?
``` mutations in DNA can cause: checkpoints not to work properly unresponsiveness to crowding unlimited number of cell dividion CANCER ```
33
benign tumor
growing mass of cells that pose no threat to life
34
malignant tumor
growing mass of cells that may invade or destroy healthy tissue (cancer)
35
metastasis tumor
malignant cells that travel beyond original cite of growth
36
Carcinogen tumor
any substance that causes cancer
37
carcinomas
cancer of the skin and tissue that line the organs of the body
38
lymphomas tumor
cancer of the lymphatic tissue
39
leukemia tumor
cancer of white blood cells
40
how does mitosis work? what are the stages?
divides nucleus so both daughter cells are genetically identical 1. prophase 2. metaphase 3. anaphase 4. telophase
41
prophase
1. nuclear envelope and nucleoli disappear 2. chromatin condenses into chromosomes 3. centrioles (in chromosomes) separate to opposite sides 4. mitotic spindles radiate from centrosome
42
metaphase
1. chromosomes connected to spindle fibers at centromere | 2. chromosomes arranged across center of cell
43
anaphase
1. sister chromatids pulled apart into individual chromosomes
44
telophase
1. Nuclear envelope forms around each set of chromosomes to form two nuclei 2. chromosomes turn back into chromatin 3. Nucleoli reappear
45
how does the rest of the cell divide?
cytokinesis
46
cytokinesis
divides cytoplasm into two cells during telophase
47
cytokinesis in animal cells
cleavage furrow forms | ring of microfilaments contracts and pinches cell into two cells
48
cytokinesis in plant cells
vesicles from golgi bodies join at a midline and form cell plate cell plate becomes cell wall and divides cell into two cells
49
how are haploid gametes form?
meiosis
50
what is meiosis
reduction division, if it doesn't happen zygote won't form produces daughter cells with half genetic information of parents sperm and egg each have 23 chromosomes (1n) sperm (1n) + egg (1n) = zygote with 46 chromosomes
51
meiosis 1
homologous chromosomes seperate and from haploid cell
52
meiosis 2
sister chromatids seperate
53
meiosis 1- prophase 1
tetrad forms- homologous chromosomes pair together crossing over occurs DNA exchanged between chromatids of homologous pairs source of genetic variation in species centrosomes move to opposite poles spindle fiber forms
54
meiosis 1- metaphase 1
spindle fibers attach to centromeres | random alignment of tetrads at midline of cell
55
meiosis 1- anaphase 1
homologous from tetrads randomly separate to opposite poles | independent assortment- source of variation in species
56
telophase 1 and cytokinesis
chromosomes reach opposite poles two nuclei now formed with half the chromosomes (1n) each chromosomes contains two chromatids cytokinesis occurs
57
prophase 2
no tetrads no crossing over
58
metaphase 2
chromosomes align singly on metaphase plate (no tetrads)
59
anaphase 2
sister chromatids separate now each called a chromosome | chromosomes migrate to opposite poles
60
telophase 2
each cell contains half the chromosomes (1n)
61
gametognensis
formation of gametes (sperm or egg)
62
oogenesis
formation of eggs in ovaries one large (1n) egg cell and three small (1n) polar body cells formed by meiosis due to unequal cytokinesis
63
spermatogenesis
formation of sperm in testes | four (1n) sperm cells formed by meiosois

Biology Honors (13 decks)

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