2.1 Cell Structure

Question 1

What is magnification?

Answer 1

How much bigger the image is that the specimen.

Question 2

What is resolution?

Answer 2

The ability to clearly distinguish the individual parts of an object.

Question 3

What is the resolution and magnification of a light microscope?

Answer 3

Resolution = 200nm, Magnification = 1500

Question 4

What can you see using a laser scanning microscope?

Answer 4

Images at different depths. They use laser beams to scan a specimen usually tagged with a fluorescent light, which is focused through a pinhole. A detector is hooked up to a computer and a 3 D image is made.

Question 5

What can you see using a transmission electron microscope?

Answer 5

Organelles. Electromagnets are used to focus a beam of electrons which is then transmitted through the specimen. Denser parts absorb more light so look darker on the image.

Question 6

What can you see using a scanning electron microscope?

Answer 6

Cell surfaces. They scan a beam of electrons across the surface, which knock the electrons from the specimen which are gathered into a cathode Ray. A 3D image is produced.

Question 7

What is the magnification and resolution of a transmission electron microscope?

Answer 7

Resolution = 0.2 nm Magnification = 1,000,000

Question 8

What is the magnification and resolution of a scanning electron microscope?

Answer 8

Resolution = 2nm Magnification = 100,000

Question 9

How do you use a light microscope?

Answer 9

1. Select the lowest power objective lens 2. Use the coarse adjustment knob to bring the stage to just below the objective lens. 3. Move the stage down until it’s roughly in focus. 4. Use the fine adjustment knob until you have a clear image.

Question 10

Why do you stain samples?

Answer 10

Some objects may be transparent so you can stain them. Some parts of the object take up more of the dye than others so the contrast makes different parts show up.

Question 11

What is the function of the nucleus?

Answer 11

It is the control centre of the cell. It stores the genome and transmits genetic information that provides instructions for protein synthesis.

Question 12

What is the function of the RER?

Answer 12

It is responsible for the synthesis of proteins, as it is covered in ribosomes.

Question 13

What is the function of the SER?

Answer 13

It is responsible for the synthesis of lipid and hormones.

Question 14

What is the function of the Golgi apparatus?

Answer 14

It is where proteins and packaged and modified.

Question 15

What is the function of lysosomes?

Answer 15

They are filled with hydrolytic enzymes that ingest and digest broken or unused parts of the cell.

Question 16

What is the function of chloroplasts?

Answer 16

They are the site of photosynthesis in plants.

Question 17

What is the function of the mitochondria?

Answer 17

• Produce ATP (Adenosine triphosphate), a nucleotide
• ATP transports chemical energy within cells for metabolism. Every cell uses ATP for energy. It consists of a base (adenine) and three phosphate groups.

Question 18

What is the function of the vacuole?

Answer 18

It is filled with cell sap to help support plants.

Question 19

What is the function of centrioles?

Answer 19

centrioles are involved in spindle formation during mitosis.

Question 20

What is the function of Cillia?

Answer 20

They move bacterial cells away from danger and towards food.

Question 21

What is the function of the cytoskeleton?

Answer 21

Complex system of microtubules that form a kind of road that motor proteins transport things along.

Question 22

How do you make and secrete a protein?

Answer 22

The protein is transcribed in the nucleus then translated in the RER. Vesicles are pinched off and moved to the Golgi where they are modified. Vesicles are pinched off and then fuse with the plasma membrane and are released.

Question 23

What is a prokaryotic cell wall made from?

Answer 23

Peptidoglycan.

Question 24

What are the differences between prokaryotic and eukaryotic cells?

Answer 24

prokaryotic cells do not have a nucleus or any membrane bound organelles. They have 70s ribosomes (smaller) and the DNA is naked, not wound round a histone protein.