Chromosomes carry genetic information in a molecule called DNA. A type of cell division called mitosis ensures that when a cell divides each new cell produced has the same genetic information.
Which statement is true of genes?
A gene is a short section of DNA that codes for a protein
A single molecule of DNA
Humans have 46 genes
How many chromosomes does a human have in each body cell?
Which statement is correct about the cells produced by mitosis?
Two daughter cells are produced, each has the same number of chromosomes as the parent cells
Four daughter cells are produced, each has the same number of chromosomes as the parent cells
Two daughter cells are produced, each has half the number of chromosomes as the parent cells
What happens in the stage that is before mitosis in the cell cycle?
A period of DNA synthesis
The cytoplasm separates
A period of growth, during which time DNA is checked for errors
Which statement about stem cells is incorrect?
Embryonic stem cells can differentiate into more different cell types
Adult stem cells are limited to the bone marrow in adults
Bone marrow transplants use embryonic stem cells
A scientist observes 100 cancer cells with a microscope.
If 16 cells are undergoing mitosis, and the length of the cell cycle is 400 hours, what is the length of mitosis?
Which of the following is an ethical consideration about the use of embryonic stem cells?
In some cases embryos are being produced just so that stem cells can be extracted for research on therapies.
Transplants of stem cells from donors might transfer viruses to patients.
It is important to inform the public about the pros and cons of embryonic stem cell transplants.
Which statement is correct of plant stem cells?
Plant stem cells are identical in structure to animal stem cells
Plant stem cells are the elongated cells below the tip of the shoot
Plant stem cells occur in meristems
Why are meristematic cells grown in a sterile culture medium?
A culture medium that is sterile contains the correct nutrients
To avoid the growth of microorganisms
To reduce costs
What are guard cells in plants specialised to do?
Provide energy for the transport of sugars
Open and close to let carbon dioxide into the leaf for photosynthesis