Wk 2

Question 1

What are the components of the plasma membrane?

Answer 1

• Phospholipids
• Proteins
• Carbohydrates
• Cholesterol

Question 2

What are the functions of the plasma membrane?

Answer 2

• Barrier separating the inside and outside of the cell
• Controls the passage of materials between the inside & outside of the cell.
• Allows the cell to be identified to other cells
• Involved in intracellular signalling

Question 3

What are the types of membrane transport?

Answer 3

Passive (no energy required - moves down conc. gradient)

Primary Active (energy required - moves up conc. gradient)

Secondary Active (energy required - moves up conc. gradient)

Question 4

What are the types of passive transport?

Answer 4

Simple Diffusion: moves through the lipid bilayer of membrane.

Facilitated Diffusion (proteins helping move molecule through):
- Channel mediated diffusion; solute moves down conc. gradient through channel
- Carrier mediated diffusion; solute binds to carrier to be transported
- Osmosis diffusion; water moves from high conc. to lower conc.

Question 5

What is primary active transport?

Answer 5

Na+/K+ Pump:
- Energy is obtained by hydrolysis of ATP to ADP
- Changes the shape of a carrier protein
- “Pumps” a substance across the membrane

Question 6

What is secondary active transport?

Answer 6

• Involves two molecules passing through simultaneously
• Energy is taken from the ions that passively leaking back through the cell
• Energy is released allowing other substances to pass through the membrane against their own concentration gradient at the same time

Question 7

What are symporters?

Answer 7

Move TWO substance across the membrane in the same direction.

Question 8

What are Antiporters?

Answer 8

Move TWO substance across the membrane in different directions.

Question 9

What is a nucleus?

Answer 9

• Controls the cellular structure
• Produces ribosomes in nucleoli
• Directs cellular activities
• Houses genetic information

Question 10

What are the types of endoplasmic reticulum (ER)?

Answer 10

Rough Endoplasmic Reticulum (RER)
- Producing, transporting and storing proteins to be exported to the outside of the cell

Smooth Endoplasmic Reticulum
- Carbohydrate or lipid or steroid synthesis
-Enzymatic degradation (detoxification)
- Special role in muscles

Question 11

What are ribosomes?

Answer 11

• Responsible for protein synthesis: translation (make proteins)

Question 12

What is the golgi appartus?

Answer 12

• Modifies, sorts, packages and transports proteins from ER

Question 13

What are lysosomes?

Answer 13

• Formed from the golgi apparatus
• Contain powerful digestive enzymes

Autophagy – digestion of organelles
Autolysis – destroy the cell

Question 14

What is mitochondria?

Answer 14

• Generate ATP with aerobic cellular respiration
• Powerhouse of the cell

Question 15

What is endocytosis?

Answer 15

Cell acquires material from extracellular space/fluid (move things into cell).

Question 16

What is exocytosis?

Answer 16

Materials move out of cell into the extracellular space (eliminate things from cell).

Question 17

What are the stages of the cell cycle?

Answer 17

Interphase - cell maintains and carries out normal metabolic functions preparing for division.

Mitotic phase - cell divides in two.

Question 18

What are the enzymes that assist in DNA replication?

Answer 18

Cyclin Dependent Protein Kinases (CDKs) - initiation and regulation of the DNA replication.

Cyclins (cellular protein) - responsible for turning CDKs on.

Question 19

What are the stages of Interphase?

Answer 19

G1 Phase
- Growth

S Phase (synthesis)
- Growth
- DNA replication

G2 Phase (makes more organelles)
- Growth

*Centrioles split and separate.

Question 20

What are the stages of Mitosis (somatic cells)?

Answer 20

1. Prophase (spindle fibres form from centriole, chromosomes form)
2. Metaphase (chromosomes line up down the middle)
3. Anaphase (chromosome pulled to opposite ends)
4. Telophase (spindle fibres break)
5. Cytokinesis (2 separate cells are formed)

*46 chromosomes, Diploid cells (2n)

Question 21

What are the stages of Meiosis I?

Answer 21

1. Prophase I
   - synapsis occurs which allows for genetic variation (maternal/paternal replicated chromosomes pair up)
   - Four sister chromatids (tetrad)
   - Crossing over occurs (to mix up genes)
2. Metaphase I
   - chromosomes line up in pairs
   - spindle fibres attach to centromeres (different to mitosis)
3. Anaphase I
   - Pairs separated and pulled to opposite ends of cell
4. Telophase I/Cytokinesis
   - Produces 2 new cells

*23 replicated chromosomes, 2 haploid cells (n)

Question 22

What are the stages of Meiosis II?

Answer 22

Prophase II
- Spindle fibres form from centromere
- NO crossing over

Metaphase II
- Align the replicated chromosomes along the equator

Anaphase II
- Sister chromatids pulled apart to opposite ends of cell

Telophase II/Cytokinesis
- 4 new genetically different daughter cells are created

*23 chromosomes only, 4 haploid cells (n)

Question 23

What are stem cells?

Answer 23

Stem cells are cells that can turn into other cell types.
- can replace cells and tissues that have been lost/damaged to disease.

Question 24

What are the types of stem cells?

Answer 24

Pluripotent - can turn into any cell

Multipotent - can turn into specific cell types

Totipotent - can form an entire organism