Chapter 2.1 - cell division

Question 1

Mitosis is for _______________

Throughout your life cells continued to be replaced as they are worn out.

Answer 1

repair and growth of cells.

Question 2

What types of cells aren’t constantly dying and being replaced

Answer 2

nerve and brain

Question 3

WE grow from a single cell to a trillion cells (person) via the _____________

Answer 3

cell cycle.

Question 4

Which rate of the cell cycle is variable? ie which stage takes different time -sometimes long/sometimes short

Answer 4

Stage 1 - Most variable in length - Cell grows bigger and increases in mass and carries out its normal cell activities.
At this stage the cell is storing energy (takes more time)
As it is carrying out it’s function each cell has a different function so each type of cell would have a different length of time.
Stage 2 and 3 are relatively quick and energy expending

Question 5

When will the cell cycle be more rapid in a human?

Answer 5

Whenever more cells are needed eg during periods of growth therefore in the embryo and infant stages

Question 6

Which stage in the cell cycle takes the longest time

Answer 6

Stage 1

Question 7

When will the cell cycle be very slow in a human?

Answer 7

In an old person - they aren’t growing anymore

- terminally sick person (cancer) - they can’t repair anymore

Question 8

What is mitosis?

Answer 8

cell division in the cell cycle to produce two identical cells.

Question 9

As a result of mitosis all your normal body cells have the same _____________

Answer 9

chromosomes

Question 10

Explain what happens in the 3 stages of cell division

Answer 10

Stage 1 - Longest stage in cell cycle

• Grows bigger, increases mass and carries out normal cell activities
• Most IMPORTANTLY replicates their DNA to form 2 copies of each chromosomes ready for cell division
• Also increases the number of sub-cellular structures (mitochondria, ribosomes and chloroplasts) ready for cell division

Stage 2 - Mitosis in chromosomes is pulled to each corner of the dividing cell
- nucleus divides

Stage 3 The cytoplasm and cell membranes also divide to form two identical daughter cells with 4 chromosomes (have exactly the same DNA)

Question 11

_____________________ have the shortest cell cycle. The embryonic cells divide RAPIDLY /SLOWLY in order to make different cells present in the body and growth. They have a short lifespan.

Answer 11

embryonic cells

rapidly

Question 12

Why are plant stem cells different from humans

Answer 12

Plants can differentiate all through their lives. Even when they differentiate they can change (it’s not permanent)