SB1. Key Concepts in Biology - Cells

Question 1

SB1b - How are animal cells different to plant cells?

Answer 1

• Animal cells, do not have cell walls, chloroplasts or vacuoles like plants do.
• They only have nuclei, ribosomes, mitochondria, cytoplasm and a cell surface membrane.

Question 2

SB1b - Describe the function of each of these subcellular organisms in Eukaryotic cell:

Cell Membrane -

Nucleus -

Cytoplasm -

Mitochondria -

Ribosomes -

Cell Wall -

Chloroplasts-

Vacuole -

Answer 2

• Cell membrane: controls what enters and leaves the cell
• Nucleus: contains DNA that controls cell activities
• Cytoplasm: fills the cell and where reactions occur
• Mitochondria: Where respiration takes place
• Ribosomes: Where protein synthesis takes place Plant only:
• Cell wall: Protects the cell
• Chlorplasts: Contain chlorophyll used in photosynthesis
• Vacuole: Stores cell sap

Question 3

SB1c - What are the adaptations of the following cells:

• Egg cell
• Sperm cell
• Cilliated epithelial cell
• Cells lining the small intestine

Answer 3

• Egg cell: Has a haploid nucleus, with a special cell membrane to allow only one sperm cell in and many nutrients in its cytoplasm
• Sperm cell: Has an acrosome with enzymes to penetrate the egg cell with lots of mitochondria and a tail to swim
• Ciliated epithelial cell: Lined with cilia and packed with mitochondria this allows the cell to have a ‘wavy’ movement to move an egg along
• Microvilli: The cells lining the small intestine have small folds called microvilli which increase its surface area making absroption easier

Question 4

SB1c - What is the function of a gamete?

Answer 4

• Gametes are sex cells used in reproduction.
• Examples are sperm and egg cells.