Unit 2 - Components of a cell

Question 1

Describe the function of the nucleus.

Answer 1

• Controls the cell by controlling the production of mRNA and tRNA.
• Contains DNA stored as chromosomes.
• Manufactures ribosomal RNA

Question 2

Adaptations of the nucleus.

Answer 2

Nuclear pores embedded in nuclear envelope allow mRNA & ribosomes to pass-through -Double membrane

Question 3

Describe the function of the mitochondrion.

Answer 3

-The site of the aerobic stages of respiration and therefore releases ATP during respiration from substances like glucose.
FOR = …

• Double membrane with inner membrane folded into cristae to provide a large surface area for the attachment of enzymes in respiration

Question 4

Describe the function of chloroplasts.

Answer 4

• Photosynthesis (Double membrane)
• Contains DNA and chlorophyll to carry out photosynthesis
  1 disc=thylakoid(contain chlorophyll)
  1 stack=granum
  multiple stacks=grana
  Fluid filled matrix = Stroma

Question 5

Describe the function of the smooth endoplasmic reticulum.

Answer 5

-Synthesise store and transport lipids and carbohydrates

Question 6

Describe the function of the rough endoplasmic reticulum.

Answer 6

• Provide a large surface area for the synthesis of glycoproteins and proteins
• Coated in ribosomes which make proteins

Question 7

Describe the function of the Golgi apparatus.

Answer 7

• Modifies and packages proteins into vesicles for transport

Question 8

Describe the function of lysosomes.

Answer 8

• Fuse with vesicles and produce digestive enzymes to hydrolyse pathogens, old organelles, food molecules and cells
• Break down cells(exocytosis)

Question 9

Describe the function of Ribosomes.

Answer 9

• Site of Protein synthesis
  80S eukaryotic 70S prokaryotic

Question 10

Describe the function of the Cell wall.

Answer 10

-Provide mechanical strength and support to the cell and the plant
-made of Murein in prokaryotes, cellulose in eukaryotes

Question 11

Describe the function of the vacuole.

Answer 11

• Acts as temporary storage, contains cell sap
• Maintain cell structure

Question 12

.Describe the specialised eukaryotic cells.

Answer 12

-Red blood cells – no nucleus or organelles to increase the volume for haemoglobin

-Ciliated epithelial cells – increases the surface area

-Leaf palisade cells – contain dense chloroplasts for photosynthesis

Question 13

Describe 2 Structures found only in Prokaryotic cells.

Answer 13

-Flagellum(NOT ALL/CAN HVE MORE THAN 1) - Movement of bacteria
-Mesosome - inner foldings of the cell membrane.

Question 14

Describe 2 Structures found only in Prokaryotic cells.

Answer 14

• Slimy(Protein) capsule - Reduce water loss & protect from phagocytosis
• Plasmid(can have more than 1) - small circles of DNA carrying a few genes

Question 15

Describe 3 structures found in a virus

Answer 15

NON LIVING ORGANISMS
- DNA or RNA
- Protein coat called a capsid
- Attachment proteins on the outside

Question 16

Define a Eukaryotic and Prokaryotic Cell

Answer 16

(bigger)Eukaryotic - DNA contained in the nucleus, contains membrane-bound specialised organelles
(smaller)Prokaryotic - DNA ‘free’ in the cytoplasm, no membrane-bound organelles