1. We use the term , cleavage, to describe mitosis in the early animal embryo .
ID: 176610 • Letter: 1
Question
1. We use the term , cleavage, to describe mitosis in the early animal embryo . During cleavage , the size of the embryo does not increase , but the number of cells does . a . Which stage of the cell cycle do these cells bypass ? b. Does the ratio of nuclear material to cytoplasm increase or decrease as cleavage progresses ? 2. Radially symmetrical animals such as jellyfish do not form the mesoderm germ layer . What body structures do you expect to find lacking or formed differently in these animals? 4. Observe the slides marked Starfish blastula. Draw a blastula you observe in the space provided and label any of the structures you can identify. 5. Did the embryo increase in size from the unfertilized egg to early cleavage? Did it increase in size at the blastula stage ? explain 6 . Approximately how many cells did you observe in the early cleavage stage embryos ? About how many cells did you observe in the late cleavage stage ? 7. If a chicken egg has been fertilized , there is often red tissue near the germinal vesicles . Had your chicken egg been fertilized ? 8. As the chick embryo increase in size , how does the yolk change? ExplainPlease, needed Asap ! 1. We use the term , cleavage, to describe mitosis in the early animal embryo . During cleavage , the size of the embryo does not increase , but the number of cells does . a . Which stage of the cell cycle do these cells bypass ? b. Does the ratio of nuclear material to cytoplasm increase or decrease as cleavage progresses ? 2. Radially symmetrical animals such as jellyfish do not form the mesoderm germ layer . What body structures do you expect to find lacking or formed differently in these animals? 4. Observe the slides marked Starfish blastula. Draw a blastula you observe in the space provided and label any of the structures you can identify. 5. Did the embryo increase in size from the unfertilized egg to early cleavage? Did it increase in size at the blastula stage ? explain 6 . Approximately how many cells did you observe in the early cleavage stage embryos ? About how many cells did you observe in the late cleavage stage ? 7. If a chicken egg has been fertilized , there is often red tissue near the germinal vesicles . Had your chicken egg been fertilized ? 8. As the chick embryo increase in size , how does the yolk change? Explain
Please, needed Asap ! a . Which stage of the cell cycle do these cells bypass ? b. Does the ratio of nuclear material to cytoplasm increase or decrease as cleavage progresses ? 2. Radially symmetrical animals such as jellyfish do not form the mesoderm germ layer . What body structures do you expect to find lacking or formed differently in these animals? 4. Observe the slides marked Starfish blastula. Draw a blastula you observe in the space provided and label any of the structures you can identify. 5. Did the embryo increase in size from the unfertilized egg to early cleavage? Did it increase in size at the blastula stage ? explain 6 . Approximately how many cells did you observe in the early cleavage stage embryos ? About how many cells did you observe in the late cleavage stage ? 7. If a chicken egg has been fertilized , there is often red tissue near the germinal vesicles . Had your chicken egg been fertilized ? 8. As the chick embryo increase in size , how does the yolk change? Explain
Please, needed Asap !
Explanation / Answer
Ans1a : During cleavage the cells by pass the gap phases, G1 and G2 phases because the cells are under rapid division and mainly devoted to mitosis and cytokinesis.
Ans1 b: The ratio of nuclear material to cytoplasm increases as there is rapid division of cells, lacking an increase of cell mass that is DNA replication occurs rapidly but no cytoplasmic material is added.
Ans 2:Diploblastic animals like Jellyfish do not form mesoderm germ layer hence there will be no visceral organs like stomach and intestine rather they will have an open gastrovascular cavity or gelatinous matrix.
Ans 4: During early blastula we are able to find blastomeres lining the wall but in late they become so small that not easy to distinguish individual blastomeres. The hollow cavity blastocoel remains at the center.
Ans 5.No the embryo does not increase in size from unfertilized to early cleavage. No it did not increase in blastula stage. As there is no cytoplasmic mass addition only rapid mitosis occurs during cleavage.
Ans 5.No the embryo does not increase in size from unfertilized to early cleavage. No it did not increase in blastula stage. As there is no cytoplasmic mass addition only rapid mitosis occurs during cleavage.
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