Cells

Question 1

What is the structure of the Rough ER?

Answer 1

A series of flattened sacs enclosed by a membrane with ribosomes on the surface

Question 2

What is the function of the Rough ER?

Answer 2

• Folds and processes proteins made on the ribosomes.

Question 3

What is the structure of the Smooth ER?

Answer 3

A system of membrane bound sacs

Question 4

What is the function of the Smooth ER?

Answer 4

Produces and processes lipids

Question 5

What is the function of the golgi apparatus?

Answer 5

Processes and packages proteins & lipids
Produces lysosomes

Question 6

What is the structure of lysosomes?

Answer 6

Vesicles containing digestive enzymes bound by a single membrane

Question 7

What is the structure of the golgi apparatus?

Answer 7

A series of fluid filled, flattened & curved sacs with vesicles surrounding the edges

Question 8

What is the structure of mitochondria?

Answer 8

Oval shaped & bound by a double membrane (envelope)
Inner membrane is folded to form cristae with a matrix on the inside containing the enzymes needed for respiration

Question 9

What is the structure of centrioles?

Answer 9

Hollow cylinders containing a ring of microtubules arranged at right angles to eachother

Question 10

What is the structure of ribosomes?

Answer 10

Composed of two sub units

Question 11

What is the function of ribosomes?

Answer 11

The site of protein production

Question 12

What is the structure of the cell wall?

Answer 12

Rigid outer covering made of peptidoglycan

Question 13

What is the structure of plasmids?

Answer 13

Circular piece of DNA

Question 14

What is the structure of capsule?

Answer 14

Protective slimy layer which helps the cell to retain moisture and adhere to surfaces

Question 15

What is the structure of the flagellum?

Answer 15

A tail like structure which rotates to move the cell

Question 16

What is the structure of pili?

Answer 16

Hair like structures which attach to other bacterial cells

Question 17

What is the structure of mesosomes?

Answer 17

Infoldings of the inner membrane which contain enzymes required for respiration

Question 18

What is the function of ribosomes?

Answer 18

Site of protein production

Question 19

What is the structure of the nucleus

Answer 19

A double membrane called the envelope
Contains 3000 nuclear pores enabling molecules to leave & enter
Jelly like material (nucleoplasm) makes up most of the nucleus
Contains Chromatin

Question 20

Magnification of a optical microscope

Answer 20

×1500

Question 21

Resolution of an optical microscope

Answer 21

0.2 micrometers

Question 22

Magnification of electron microscope

Answer 22

×1,500,000

Question 23

Resolution of an electron microscope

Answer 23

0.0002 micrometers

Question 24

Limitations of an electron microscope

Answer 24

• The whole system must be in a a vacuum so living specimens cannot be observed
• The complex staining process is required which may introduce artefacts into the image
• Specimens have to be very thin, particularly for TEM so that electrons can pass through
• SEM has a lower resolving power than TEM, but both have greater resolving power than a light microscope.

Question 25

Difference between TEM & SEM?

Answer 25

SEM can create 3D images TEM has a higher resolving power than SEM

Question 26

Why is a cold,buffered and isotonic solution used in homogenisation?

Answer 26

Cold - slows down enzymes activity Buffered - maintains a constant pH Isotonic - prevents osmosis (same water potential)

Question 27

How does a TEM work?

Answer 27

Uses electromagnets to focus a beam of electrons. The beam if then transmitted throughout the specimens. Different parts with have different densities, denser regions absorb more electron.

Question 28

How does a SEM work?

Answer 28

Scans a beam of electrons across a specimen. The beam knocks electrons off the specimen. These electrons are then collected in a cathode ray tube, forming an image.

Question 29

What is mitosis used for?

Answer 29

Growth, repair & reproduction

Question 30

Stages of mitosis

Answer 30

Prophase Metaphase Anaphase Telophase

Question 31

What happens during prophase?

Answer 31

-Breakdown of nuclear membrane -Spindle fibres appear -Chromosomes condense

Question 32

What happens during prometaphase?

Answer 32

-Spindle fibres attach to chromosomes -Chromosomes condense

Question 33

What happens during metaphase?

Answer 33

- chromosomes align

Question 34

What's happens during anaphase

Answer 34

-centeomere divide -sister chromatides move to opposite poles

Question 35

What happens during telophase?

Answer 35

-Nuclear membrane reforms -Chromosomes decondense

Question 36

Why doesn't mitosis give a rise to genetic variation?

Answer 36

All cells produced are genetically identical

Question 37

What happens during interphase?

Answer 37

The cell grows & prepares to divide. The chromosomes & some organelles are replicated, chromosomes also begin to condense.

Question 38

What happens during cytokinesis?

Answer 38

The parent & replicated organelles move to opposite sides of the cell & the cytoplasm divides creating two daughter cells.