Cellular Division

Question 1

DNA of prokaryotes is?

Answer 1

one circular chromosome attached to inside of cell membrane

Question 2

eukaryotic cells store genetic info in chromosomes

Answer 2

10-50 chromosomes in cells.
humans have 23 pairs (46 chromosomes)

Question 3

Each chromosome is comprised of?

Answer 3

A single DNA molecule

Question 4

chromosomes can’t be seen when cells aren’t dividing and are called?

Answer 4

chromatin

Question 5

DNA is tightly coiled around proteins called?

Answer 5

HISTONES

Question 6

duplicated chromosomes are called chromatids and are held together by?

Answer 6

centromere

Question 7

first 22 pairs are called?

Answer 7

autosomes

Question 8

last pair is?

Answer 8

Alosome - sex chromosome (XX female, XY male)

Question 9

asexual reproduction types?

Answer 9

mitosis and binary fission

Question 10

sexual reproduction involves?

Answer 10

egg and sperm to form zygote (not identical to parent)
meiosis is eg

Question 11

cell cycle consists of?

Answer 11

interphase, mitosis, cytokinesis

Question 12

interphase consists of?

Answer 12

G1 - primary growth
S - synthesis (DNA replicated)
G2 - secondary growth phase

Question 13

what happens in G1 stage?

Answer 13

cells mature by making more cytoplasm and organelles

Question 14

what happens in S stage?

Answer 14

DNA is replicated

Question 15

what happens in G2 stage?

Answer 15

all cell structres needed for division are made (centrioles).
organelles and proteins are synthesised

Question 16

what is mitosis?

Answer 16

division of nucleus (happens only in eukaryotes)
aka karyokinesis
doesnt occur in brain cells

Question 17

4 mitotic stages?

Answer 17

prophase, metaphase, anaphase, telophase

Question 18

what happens in early prophase?

Answer 18

chromatin in nucleus condenses to form visible chromosomes
mitotic spindle forms from fibers in cytoskeleton or centrioles

Question 19

what happens in late prophase?

Answer 19

nuclear membrane and nucleolus are broken down.
spindle fibres called KINETOCHORES attach to centromere.
spindle finishes forming

Question 20

spindles form from what?

Answer 20

microtubules in plants.
centrioles in animals.

Question 21

what happens in metaphase?

Answer 21

chromosomes which are attached to kinetochore fibres move to centre of the cell.
chromosomes are at the EQUATOR.

Question 22

what happens in anaphase?

Answer 22

sister chromatids are pulled appart to opposite poles of the cell by kinetochore fibres

Question 23

what happens in telophase?

Answer 23

spindle disassembles.
nuclear envelope forms around each set of sister chromatids.
nucleolus reappears.
CYTOKINESIS occurs.
chromosomes reappear as chromatin,

Question 24

what is cytokinesis?

Answer 24

division of cytoplasm.
cell plate in plant cells.
cleavage furrow in animal cells.

Question 25

properties of daughter cells of mitosis?

Answer 25

same number of chromosomes as parent cell.
identical to each other but smaller than parent.

Question 26

Diploid number??

Question 27

What are special proteins that increase chances that a normal cell develops into a tumor cell?

Answer 27

ONCOGENES

Question 28

meiosis: how many chromosomes does daughter cell have?

Answer 28

half of original cell (parent cell is diploid, splits into 3 monoploid cells)

Question 29

meiosis in testes?

Answer 29

SPERMATOGENESIS

Question 30

meiosis in ovaries?

Answer 30

OOGENESIS

Question 31

2 haploid games come together to form what?

Answer 31

a diploid zygote

Question 32

same genes, same alleles = ?

Answer 32

sister chromatids

Question 33

same genes, different alleles = ?

Answer 33

homologs (they separate in meoisis I)

Question 34

meoisis must reduce chromosome number by half because?

Answer 34

fertilization restores 2n number

Question 35

in meoisis I, homologs separate

Answer 35

in meoisis II, sister chromatids separate

Question 36

meoisis: early prophase?

Answer 36

homologs pair up, crossing over happens

Question 37

meoisis: late prophase?

Answer 37

chromosomes condense and spindle forms

Question 38

2 homologous chromosomes join to form a?

Answer 38

TETRAD (called synapsis)

Question 39

meoisis: metaphase I?

Answer 39

homologoues pairs of chromosomes align along equator

Question 40

meoisis: anaphase I?

Answer 40

homologs separate and move to opposite poles.
sister chromatids remain attached at their centromeres

Question 41

meoisis: telophase I?

Answer 41

nuclear envelopes reassemble.
spindle disappears.
cytokinesis.