Eukaryotic Cells

Question 1

What is the structure of the NUCLEUS?

Answer 1

• Large, spherical membranes bound organelle
• Near centre of the cell
• Around 6 μm in diameter
• 10% of cell volume
  BUT can be oval, flattened, tiny, lobed.

Question 2

What is the structure of the ENDOPLASMIC RETICULUM?

Answer 2

• ‘Little net within the cytoplasm’
• intricately folded membrane
• 50% of the membrane in the cell
• Vesicles can bud off into transport proteins to Golgi Body

Question 3

What is the structure of the GOLGI APPARATUS?

Answer 3

• 4 to 6 flattened, smooth membrane bound compartments w/ associated vesicles
• Slightly concave, polarised structure

Question 4

What is the structure of the LYSOSOMES?

Answer 4

• Vesicles full of digestive enzymes that work best @ pH = 5

- 1μm in size

Question 5

Why do the enzymes in LYSOSOMES work at a different pH to our cytosol (liquid in cytoplasm @ pH=6.9)?

Answer 5

So they don’t digest the things that they aren’t supposed to.

Question 6

How do LYSOSOMES create their own enzymatic pH?

Answer 6

Proteins in lysosomal membrane pump H+ ions from the cytosol into lysosome.

Question 7

Why do LYSOSOMES create their own enzymatic pH?

Answer 7

Enzymes are v sensitive to pH as they are proteins, so any pH change affects the structure.

Question 8

What is the structure of the MITOCHONDRIA?

Answer 8

• Fairly large

- Double membrane - crista = inner membrane

Question 9

What is the structure of the CYTOSKELETON?

Answer 9

• Complex network of Microtubules, Actin filaments and Intermediate filaments

Question 10

What is the function of the NUCLEUS?

Answer 10

Controls the cell,

Regulates DNA & RNA actions

Question 11

What is the structure of the NUCLEAR ENVELOPE?

Answer 11

Contains pores for RNA to move out of

Question 12

What is the function of the NUCLEAR ENVELOPE?

Answer 12

Regulates what goes in and out of Nucleus

Question 13

What is the function of the RER?

Answer 13

• Covered with ribosomes in sheet-like appearance
• COLLECTS, STORES, PACKAGES + TRANSPORTS Proteins

(Crabs Smell Putrid Today)

Question 14

What is the function of the SER?

Answer 14

• SYNTHESISES + PROCESSES Lipids

Question 15

What are the 3 functions of the GOLGI?

Answer 15

1. Protein Modifications
   - Addition of sugars, fatty acids + phosphate groups
2. Protein Processing
3. Protein sorting + localisation
   - ‘Post office job’
   - Molecules and chemicals transported to areas where they are needed in+out of cell
   - Occurs in TGN (trans Golgi network)

Question 16

What is the function of the LYSOSOMES?

Answer 16

• Digest macromolecules
• Clean up broken down organelles
• Can be used to kill cells when they need to be destroyed = ‘apoptosis’

Question 17

What is the function of the MITOCHONDRIA?

Answer 17

• Energy Conversion, ATP Generation

- Oxidative phosphorylation, converting food energy + fatty acids into ATP through ETCs + proton gradients

Question 18

What is the function of the CYTOSKELETON?

Answer 18

• Cell Motility and intracellular movement (motor proteins)
• Support framework for the cell
• Gives cell its shape

Question 19

Why do we need to move things around the cell?

Answer 19

• Movement of organelles (microtubules)
• Movement of vesicles (microtubules)
• Whole cell movement is polarised + directional
• Movement is important in development