Cell Structure And Membranes 1.3

Question 0

What is the function of the nucleus?

Answer 0

It contains the nucleolus and often chromatin. Chromatin is made from DNA and proteins. DNA controls the cells activities. The pores allow substances (RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.

Question 1

What is the function of the plasma membrane?

Answer 1

It regulates the movement of substances into and out of the cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.

Question 2

What do lysosomes contain?

Answer 2

Digestive enzymes

Question 3

Where are proteins made?

Answer 3

Ribosomes

Question 4

What is the function of the SER? And the RER?

Answer 4

The SER synthesises and processes lipids, the RER folds and processes proteins.

Question 5

What is the function of the Golgi apparatus?

Answer 5

It processes and packages new lipids and proteins. It also makes lysosomes.

Question 6

Describe the structure of a mitochondrion.

Answer 6

They’re usually oval shaped. They have a double membrane. The inner membrane is folded to form structures called cristae, inside is the matrix, which contains enzymes involved in respiration.

Question 7

What is the equation for magnification?

Answer 7

Length of image\length of specimen

Question 8

Name the two main types of microscopes.

Answer 8

Light and electron.

Question 9

Name the two main types of electron microscopes.

Answer 9

Transmission electron microscopes (TEMs) and Scanning electron microscopes (SEMs)

Question 10

Name one advantage and disadvantage of TEMs.

Answer 10

High resolution images but can only be used on thin specemins.

Question 11

What is homogenisation?

Answer 11

It is where you vibrate or grind a cell so that it breaks the plasma cell and releases the organelles into the cytoplasm.

Question 12

Outline the main steps of cell fractionation.

Answer 12

Step 1: homogenisation
Step 2: filtration
Step 3: ultracentrifugation, this is where the organelles are spun in a centrifuge. The heavier organelles sink to the bottom and form a pellet. The lighter organelles form the supernatant and are drained off.
This is done over and over again at higher and higher speeds.

Question 13

What is a triglyceride made out of?

Answer 13

4 molecules, 3 fatty acids and one glycerol molecule.

Question 14

What do all fatty acids have in common?

Answer 14

A C=O group, an OH group and a variable group (R)

Question 15

What is the difference between a phospholipid and a triglyceride?

Answer 15

Phospholipids have a phosphate group instead of a third fatty acid.

Question 16

How do you test for lipids?

Answer 16

Using the emulsion test for lipids. Shake the test substance with ethanol for a minute. Then pour the solution in water. If a lipid is present a white milky emulsion will form.

Question 17

What factors affect the rate of diffusion?

Answer 17

Concentration gradient, the higher the faster.
Thickness of exchange surface
The surface area

Question 18

What does isotonic mean?

Answer 18

When two solutions have the same water potential .

Question 19

Outline one similarity and difference between active transport and facilitated diffusion?

Answer 19

Difference: facilitated diffusion moves down the concentration gradient, whereas active transport moves against.
Similarity: they both use carrier proteins. (Carrier proteins change shape)

Question 20

How are co-transporters used in facilitated diffusion?

Answer 20

Co-transporters are a type of carrier protein.
They bind two molecules at the same time.
The concentration gradient of one of the molecules is used move the other against its own.

Question 21

How does glucose enter the blood?

Answer 21

1. Sodium ions are actively transported out of the small intestine epithelial cells, into the blood by the sodium potassium pump.
2. This decreases the the concentration of sodium in the epithelial cells so sodium ions diffuse from the small intestine lumen into the cell via the sodium-glucose transporter proteins.
3. The concentration of glucose in the cell increases so it diffuses through a channel protein into the blood.

Question 22

What are eukaryotic cells?

Answer 22

All Animal and plant cells

Question 23

Name 2 structures in a cholera bacteria which are not in a eukaryotic cell.

Answer 23

Flagellum
Plasmid
Slime capsule

Question 24

What does a ORS contain?

Answer 24

They contain large amounts of salts (sodium and chloride ions) and sugars (such as glucose and sucrose) also carbohydrates.

Question 25

Name one advantage of an ORS

Answer 25

Quick, easy to use.