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Question 1: Part A: Chromosomal DNA is duplicated during the phase of the cell cycle. a) G1 b) G2 c) Mitotic d) S Part B: Sister chromatids separate from one another during mitosis in.. a) Anaphase b) Metaphase c) Prophase d) Telophase Part C: Cells move automatically through the G1, S, G), and M phases of the cell cycle. However, movement through the cycle is also controlled at various _by internal and external factors that can either push the cell along the cycle or stop the cell from moving ahead in the cycle. a) Checkpoints b) Promoter Regions c) Regular Regions d) S Locations Part D Cancer is a group of many different diseases that all are caused by... a) Cells unable to exit the GO stage of the cell cycle b) Inability to process energy c) Loss of protein function d) Uncontrolled cell division

Answer 1

Question 1 Part A answer

Option d is the correct answer.In animal cells during S phase(synthesis phase) DNA replication starts in the nucleus and centriole duplicates in the cytoplasm.

G1(Gap1) phase represents the interval between mitosis and initiation of DNA replication.

In G2(Gap2) phase proteins are synthesised in preparation for mitosis.

M phase or mitosis phase represents the phase of actual cell division.

Part B answer

Option a is the correct answer.During anaphase centromeres split and chromatids separates and they move to opposite poles.

During prophase chromosomal material condenses to form compact mitotic chromosomes.Chromosomes are seen to be composed of two chromatids attached together at the centromer.

In metaphase spindle fibres attach to kinetochores of chromosomes and metaphasic plate formation occur.

In telophase identity of chromosome is lost as discrete elements,nuclear envelope assembles,nucleolus,ER and golgi apparatus reform.

Part C answer

Option a is the correct answer.Examples of check points are G1 checkpoint,G2 checkpoint etc.

Part D answer

Option d is the correct answer.Cancer cells lack contact inhibition.therefore they undergo uncontrolled cell division.Cancer cells have protein functions and ability to process energy.