Cleavage (characteristics, chemical changes)

Question 1

it is a series of mitotic divisions which produces a blastula

Answer 1

Cleavage

Question 2

rapid ______ transforming the unicellular zygote into a multicellular embryo

Answer 2

mitotic divisions

Question 3

true or false
in cleavage there is no growth and cells become progressively smaller

Answer 3

True

Question 4

true or false
in normal, cells have to grow in the same size as the parent before it divides, which is the same thing in cleavage

Answer 4

False (no such thing in cleavage)

Question 5

true or false
much smaller cells enclose the blastocoel in the end

Answer 5

True

Question 6

true or false
there is a change in shape during cleavage

Answer 6

False

Question 7

true or false
qualitative changes in chemical composition is minimal

Answer 7

True

Question 8

true or false
cytoplasmic displacement is minimal which is obvious in fertilization during the formation of grey crescent

Answer 8

True

Question 9

true or false
the ratio of nucleus to cytoplasm progressively decreases during cleavage

Answer 9

False (increases)

Question 10

true or false
in chemical changes during cleavage there is an increase in nuclear material at the expense of mitochondria

Answer 10

False (expense of cytoplasm)

Question 11

true or false
the increase in nuclear material is from ribonucleic acids and cytoplasm which is from high molecular weight precursors

Answer 11

False (low molecular weight precursors)

Question 12

true or false
there is an unlimited rna synthesis during cleavage

Answer 12

False (limited)

Question 13

why is it that rRNA is not synthesized during cleavage, which led the limited mrna and trna synthesis?

Answer 13

during oogenesis egg was very busy in pre and vitellogenic stages, created many transcripts already

Question 14

it is the point wherein the embryo now starts to make new transcript when there is no transcripts left that are made during oogenesis

Answer 14

midblastula transition

Question 15

true or false
the nucleus of the embryo is made up of and has components of genes coming from the sperm or zygotic

Answer 15

True

Question 16

yes or no
does mammalian egg has yolk?

Answer 16

No

Question 17

what confirm the absence of yolk in mammalian egg

Answer 17

the treatment of mammalian egg with actinomycin

Question 18

it is an antibiotic which prevents cell division because it inhibits transcription

Answer 18

Actinomycin

Question 19

how does puromycin functions?

Answer 19

by automatically stopping translation

Question 20

true or false
in sea urchin the increase of protein synthesis is drastic while in the frog the increase is not so marked

Answer 20

True

Question 21

what are the three products made because they are very important in cleavage?

Answer 21

nuclear histones, tubulin, ribonucleotide reductase

Question 22

what converts rna to dna?

Answer 22

Ribonucleotide reductase

Question 23

true or false
dna polymerases are not yet present in necessary quantities, used for dna replication

Answer 23

False (already present)