Cells

Question 1

What do all cells possess? (4)

Answer 1

1) Cell membrane
2) DNA
3) Cytoplasm
4) Ribosomes

Question 2

Characteristics of prokaryotic cells

Answer 2

• Small
• No internal membrane - bound organelles
• Examples: bacteria
• No true nucleus

Question 3

What are the functions of the plasma membrane of the cell? (3)

Answer 3

Semi permeable membrane:

1) Retention of organically produced chemicals
2) transport of molecule: diffusion, facilitated diffusion, osmosis, active transport
3) communication via receptors

Question 4

Structure of plasma membrane

Answer 4

Phospholipid bilayer
Cholesterol (inner)- prevent lysis
Proteins

Question 5

Examples of cell membrane pathologies

Answer 5

Hemoglobinopathies e.g sickle cell anaemia and thalassemia

• hereditary
• defect in haemogloblin
• alteration in lipid bilayer organisation -> decreased RBC life span
• RBC not replaced effectively

Question 6

Where in the nucleus are ribosomes constructed

Answer 6

Nucleolus

Question 7

Nuclear envelope structure allows RNA to pass through. Why?

Answer 7

• double membrane structure

- DNA can not pass. only RNA

Question 8

What is a nucleosome?

Answer 8

In eukaryotic cells, DNA wrapped around a histone

Question 9

What is a chromatin?

Answer 9

condensed DNA and proteins that form chromosomes. Found in the nucleus. The sections are telomere, centromere and arm

Question 10

Where does Transcription occur?

Answer 10

In the nucleus

RNA polymerase is used to copy DNA into RNA

Question 11

What is the function of ribosomes?

Answer 11

facilitate protein translation