Life at the Cellular Level

Question 1

Difference between passive and facilitated transport?

Answer 1

• Both require conc. gradients

- Facilitated needs carrier molecules

Question 2

Define endocytosis

Answer 2

Invagination of the cell membrane to take in extracellular materials

Question 3

Define exocytosis

Answer 3

• Vesicle produced
• Internally made proteins put inside vesicle
• Vesicle fuses with cell membrane and constituents move out

Question 4

Role of an occluding/tight junction

Answer 4

• Waterproof
• Seals gap in-between cells
• Stops absorbed nutrients from returning in-between the cells

Question 5

Role of adherens junction?

Answer 5

• Uses actin

- Connects two cells to each other to allow uniform movement

Question 6

Role of desmosomes

Answer 6

• Uses intermediate filaments

- Connects two cells to each other to allow uniform movement and structure

Question 7

Which of the two adhering junctions is stronger?

Answer 7

Desmosomes

Question 8

Role of gap junctions

Answer 8

Allow communication between cells

Question 9

What messenger molecules move through gap junctions

Answer 9

Small, water soluble

Question 10

What is the name of the protein that makes the pores of the mitochondria?

Answer 10

Porin

Question 11

What shape is mitochondrial DNA found?

Answer 11

Circular

Question 12

3 things found in the nucleus?

Answer 12

• DNA
• Nucleoproteins
• RNA

Question 13

Where is rRNA synthesised?

Answer 13

Nucleolus

Question 14

Role of the rough ER?

Answer 14

• Protein modification and transport

Question 15

Role of the golgi apparatus?

Answer 15

• Protein modification and packaging of complete polypeptides into vesicles
• Can synthesise complex polysaccharides

Question 16

What is the role of the smooth ER?

Answer 16

Breaks down 
- Drugs
- Glycogen
Synthesises 
- Lipids

Question 17

Role of lysosomes?

Answer 17

• Contain digestive enzymes so they don’t digest the cell

Question 18

Main functions of the cytoskeleton?

Answer 18

• Structure
• Motility
• Organisation of organelles
• Involved in cytoplasmic streaming

Question 19

3 parts of the cytoskeleton?

Answer 19

• Actin
• Intermediate filaments
• Microtubules

Question 20

What are intermediate filaments made of?

Answer 20

• Fibrous proteins

Question 21

What are microtubules made of?

Answer 21

Tubulin

Question 22

Name the 10 most common elements found in the body

Answer 22

• H
• O
• C
• N
• Ca
• Na
• Cl
• P
• S
• K

Question 23

What do S groups allow to form

Answer 23

Disulphide bridges

Question 24

What is configuration?

Answer 24

The FIXED arrangement of atoms in a molecule, either cis of trans

Question 25

What are the 5 reactions that occur in the body?

Answer 25

• Breaking and forming C-C bonds
• REDOX
• Internal rearrangements
• Group transfers
• Condensation/hydrolysis

Question 26

What is conformation?

Answer 26

• The PRECISE arrangement of atoms in a molecule with FREE ROTATION

Question 27

What is the role of the peroxisome?

Answer 27

• Break down of FA’s with chains longer than 22 C’s

- Breaking down hydrogen peroxide