Cell Biology (P1)

Question 1

Name five subcellular structures that both plant and animal cells have.

Answer 1

Nucleus
Cytoplasm
Cell membrane
Mitochondria
Ribosomes

Question 2

What three things do plant cells have that animal cells don’t?

Answer 2

Cell wall
Permanent vacuole
Chloroplasts

Question 3

Where is genetic material found in animal cells?

Answer 3

Nucleus.

Question 4

Where is genetic material found in bacteria cells?

Answer 4

In the cytoplasm floating freely.

Question 5

What type of organisms are bacteria - prokaryotes or eukaryotes?

Answer 5

Prokaryotes.

Question 6

Which gives higher resolution - a light microscope or an electron microscope?

Answer 6

An electron microscope.

Question 7

What is cell differentiation?

Answer 7

The process by which a cell changes to become specialised for its job.

Question 8

Give three ways that a sperm cell is adapted for swimming to an egg cell.

Answer 8

Long tail
Streamlined head
Lots of mitochondria in the cell to provide energy

Question 9

Draw a diagram of a nerve cell. Why is it this shape?

Answer 9

The extensions help the neuron pass chemical and electrical messages quickly through the body.

Question 10

What are chromosomes?

Answer 10

Chromosomes are coiled up lengths of DNA molecules. Each chromosome carries a large number of genes controlling the development of different characteristics. Each person has two copies of each chromosome from each parent, 23 pairs in total.

Question 11

What is the cell cycle?
(Growth and replication)

Answer 11

Growth & Replication:
- In a cell that’s not dividing, the DNA is all spread out in long strings.
-Before division, the cell grows and increases the amount of subcellular structures such as mitochondria and ribosomes.
- It then duplicates its DNA so there is only one copy for each new cell.

Question 12

What is the cell cycle?
(Mitosis)

Answer 12

Mitosis is the stage where the cell divides.
- The chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell.
- Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells - the nucleus has been divided.
-Lastly, the cytoplasm and cell membrane divide.

Question 13

What is mitosis used for by multicellular organisms?

Answer 13

Replaces worn-out cells such as skin cells.

Question 14

Give two ways that embryonic stem cells could be used to cure diseases.

Answer 14

Replace faulty cells
Genetic cloning

Question 15

Why are some people against using human embryos in stem cell research?

Answer 15

For the same reason people are against abortions as it is potential human life.

Question 16

What is diffusion?

Answer 16

The gradual movement of particles from places where there are lots of them to places where there are fewer of them.

Question 17

Name three substances that can diffuse through cell membranes

Answer 17

Glucose
Amino acids
Water

Question 18

Two substances that can’t diffuse through cell membranes

Answer 18

Starch and proteins.

Question 19

What type of molecules move by osmosis?

Answer 19

Water molecules.

Question 20

Two differences between active transport and diffusion

Answer 20

Diffusion moves molecules down concentration gradient while active transport takes them against concentration gradient. Diffusion is passive, which means it does not require energy, while active transport does.

Question 21

Give three adaptations of exchange surfaces that increase the efficiency of diffusion.

Answer 21

Villi in the digestive system
Alveoli in the respiratory system
Leaves being flat

Question 22

Give two ways villi in the small intestine are adapted for absorbing food

Answer 22

A single layer of surface cells
A very good blood supply to assist quick absorption

Question 23

Explain how leaves are adapted to maximise the amount of carbon dioxide that gets to their cells

Answer 23

Leaves are adapted for photosynthesis and gaseous exchange. They are adapted for photosynthesis by having a large surface area, and contain openings, called stomata to allow carbon dioxide into the leaf and oxygen out.