Cell structure 3.2.1

Question 1

Define the term prokaryotic cell

Answer 1

DNA is free in the cytoplasm

Question 2

Define the term eukaryotic cell

Answer 2

DNA is incased in the nucleus and contains membrane bound specialised organelle’s

Question 3

What is the structure and function of the cell-surface membrane?

Answer 3

fluid mosaic phospholipid bilayer with extrinsic and intrinsic proteins embedded.

• It separates cytoplasm from the extracellular environment
• selectively permeable membrane allows certain substances to enter and exit
• involved in cell recognition

Question 4

What is the role of cholesterol, glycoproteins and glycolipids in the cell surface membrane?

Answer 4

Cholesterol- steroid molecules connects phospholipids and reduces fluidity
Glycoproteins- cell signaling, cell recognition (antigens) and binding cells together
Glycolipids- cell signalling and recognition

Question 5

What is the structure and function of the nucleus?

Answer 5

• surrounded by a nuclear envelope, which is a semi-permeable double membrane
• nuclear pores allow substances to come and go
• contains DNA coiled around chromatin into chromosomes
• gene expression determines specilaisation and site
• the site of mRNA transcription, semiconservative replication and mitosis

Question 6

What is the structure and function of a mitochondrion?

Answer 6

• cristae, inner folded membrane where ETC takes place

- matrix, the fluid and the site of the krebs cycle

Question 7

What is the structure and function of chloroplasts?

Answer 7

• double membrane
• molecules of starch
• thylakoids and grana containing chlorophyll and is the site of the light-dependent reaction
• stroma, the fluid filled matrix and the site of the light-independent reaction