2(b) Cells

Question 1

Describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

Question 2

Describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

Answer 2

Nucleus
* Controls DNA and controls the activities of the cell.

Cytoplasm
* Site of chemical reactions.

Cell membrane
* Controls what enters and exits the cell. It is selectively permeable.

Cell wall
* Maintains shape of cell and provides structure made of cellulose.

Mitochondria
* Site of aerobic respiration.

Chloroplasts
* Site of photosynthesis. Contains chlorophyll.

Ribosomes
* Site of protein synthesis

Vacuole
* Stores cell sap-water, sugar and pigment.

Question 3

Know the similarities and differences in the structure of plant and animal cells

Answer 3

Both:
* Mitochondria
* Nucleus
* Cell membrane
* Ribosome
* Cytoplasm

Plant:
* Cell wall
* Vacuole
* Chloroplast

Question 4

Explain the importance of cell differentiation in the development of specialised cells

Answer 4

• It allows cells to specialize and perform specific functions in an organism..
• Differentiation is controlled by genes in the nucleus.
• It enables the formation of tissues and organs.
• Without differentiation, complex multicellular organisms would not exist.

Question 5

Understand the advantages and disadvantages of using stem cells in
medicine

Answer 5

Advantages
* Treating untreatable conditions, growing organs for transplants, and scientific research.

Disadvantages
* Embryonic stem cells can have high rejection rates.
* Adult stem cells have a determined cell type.
* Obtaining any form of stem cell is a difficult process.
* Stem cell treatments are an unproven commodity.
* Stem cell research is a costly process.
* We do not know if there are long-term side effects to worry about.