Chapter 1 - Cells

Question 1

Production and secretion of Insulin

Where it is the job of insulin and where is it made?

Answer 1

Answer:

Insulin is made in the pancreas and secreted into the bloodstream and this acts on the target (liver and muscle) cells.

Question 2

Production and secretion of Insulin

What is the first step of this process?

Answer 2

Step 1:

mRna copy of gene for insulins made in the nuclesus (transcription).

Question 3

Production and secretion of Insulin

What is the second step of this process?

Answer 3

Step 2:

mRNA leaves nucleus through nuclear pore.

Question 4

Production and secretion of Insulin

What is the third step of this process?

Answer 4

Step 3:

mRNA attaches to a ribosome in the rough endosplamic reticulum. This reads the instruction to assemble the protein.

Question 5

Production and secretion of Insulin

What is the fourth step of this process?

Answer 5

Step 4:

Insulin molecules is pinched off in vesicles and travels towards the golgi.

Question 6

Production and secretion of Insulin

What is the fifth step of this process?

Answer 6

Step 5:

Vesicle fuses with golgi.

Question 7

Production and secretion of Insulin

What is the sixth step of this process?

Answer 7

Step 6:

Golgi processes and packages this molecule of insulin.

Question 8

Production and secretion of Insulin

What is the seventh step of this process?

Answer 8

Step 7:

Packaged insulins pinched in vessicles from the golgi and this moves towards the cell surface membrane.

Question 9

Production and secretion of Insulin

What is the step 8:

Answer 9

Step 8:

Vesicle fuses with cell surface membrane.

Question 10

Production and secretion of Insulin

What is the ninth step of this process?

Answer 10

Step 9:

Excosytosis- Cell surface membrane opens and releases the insulin into blood- Stream

Question 11

Prokaryotic Cells:

What is the function of the cell wall?

Answer 11

This is made of murein/peptidogiycan unlinke eukaryotic cells made of cellulose.

Question 12

Prokaryotic Cells:

What is the function of the cell surface membrane:

Answer 12

It controls what enters and leave the cell.

Question 13

Prokaryotic Cells:

What is the function of the cytoplasm?

Answer 13

Contains cytosol, where enzymes and other solutes are dissolved + reaction occur.

Question 14

Prokaryotic Cells

What is the function of the ribosomes?

Answer 14

Protein synthesis occurs, they are smaller about 70s.

Question 15

Prokaryotic Cells

What is the function of the mesosome?

Answer 15

Highly infolded region of the cell membrane where respiration occurs.

Question 16

Prokaryotic Cells

What is the function of the bacterial DNA?

Answer 16

The DNA is found in a nucleoid without a membrane seperating it from the rest of the cell. This DNA contains genes for bacterial proteins.

Question 17

What is the differences between prokaryotic and eukaryotic cells?

Answer 17

Prokaryotic Cells

> No membrane bound organelles (golgi, ER)
Cell walls made of murein/peptidoglycan
Smaller ribosomes (70s)
Respiration takes place in mesosomes
Prokaryotic cells are much smaller (1-5micrometre)

Eukaryotic Cells

> Membrane bound organelles (ER, golgi, lysosomes)
Cell wall, made of cellulose
Bigger Ribosomes (20nm)
Respiration takes place in mitochondria
Eukaryotic cells are bigger (10-100micrometres)

Question 18

Question: What the function of each feature of the prokaryotic cells? (capsule,flagella,pili, plasmids)

What is the bacterial DNA ?

Answer 18

Capsule: A slime outer layer that protects the prokaryotes from dehydration
Flagella - Allow bacteria to move
Pili-Enable one bacterium to attach to another bacterium and exchange plasmids
Plasmids- Small loops of DNA, contain genes for antibiotic resistance.

Bacterial DNA: naked DNA that isn’t wound around histone proteins but floats in the cytoplasm as a loop.

Question 19

What is the function of lysosomes?

Answer 19

> Small bags made from the golgi aparratus
A membrane bound (has a membrane around it) Sac of Digestive enzymes (hydrolotic enzymes)
Digest worn parts of cells

Question 20

What is the function of golgi apparatus?

Answer 20

> Proteins are modified by adding sugar,lipid or being folded into their 3D shape.

> The proteins are packaged into vesicles, these are pinched off and exported or stored.

Question 21

Structure Of Nucleus (not function)

1. Describe the structure of chromatin?
2. Describe the structure of nucleolus?
3. Describe the structure of nuclear envelope?
4. Describe the structure of nuclear pore?

Answer 21

1. Chromatin: Genetic material ; DNA wound histone proteins ; cells into chromosomes when the cells dividing.
2. Nucleolus: Contains RNA ; doesnt have a membrane around it ; Ribosomes are made
3. Nuclear envelope: Has a double membrane; seperates contents from the cell to the rest of the nucleus
4. Nuclear Pore: enables mRNA to leave the nucleus ; substances such as steroid hormones from the cytoplasm can enter the nucleus from these pores.

Question 22

Mitochondria Structure (not function)

1. Describe the structure of the matrix.
2. Describe the structure of cristae.
3. State the size of a mitochondrion.

Answer 22

1. Matrix (contains enzymes –> for aerobic respiration. ATP is made and energy released.)
2. Cristae( inner membrane folded to create a large surface area to increase rate of respiration.)
3. 0.5μm-10μm

Question 23

What is the function the rough endoplasmic reticulum?

Answer 23

> This is rough because it contains ribosomes, which make protein.
This transport proteins to golgi.

Question 24

Compare the two endoplasmic reticulums?

Answer 24

Rough Endoplasmic Reticulum
>membranes containing cisternae
>coated with ribosomes
Function:
>transports substances from one pair of the cell to another (intracellular transport)
>assemble amino acids into proteins 

Smooth Endoplasmic reticulum
>membranes containing cisternae
>no ribosomes
>lipidsyntheis

Question 25

What is the golgi apparatus function?

Answer 25

> Proteins are modified here

>Proteins are packaged into vesicles and then stored in cells or released.

Question 26

Describe the two steps in photosynthesis?

Answer 26

First Stage of photosyntheis happens in the grana

Second stage in stroma

Question 27

What is the function of smooth endoplasmic reticulum?

Answer 27

No ribosomes
Synthesise lipids
Involved absorption,synthesis and transport of lipids.