cell structure

Question 1

structure and function of cell surface membrane

Answer 1

phospholipid with proteins
controls exchange of substances

Question 2

describe the nuclear envelope

Answer 2

plasma that separates the nucleus and cytoplasm

Question 3

describe the nucleolus

Answer 3

small spherical body in the nucleus that makes ribosomes

Question 4

give two structures found in all pro and eukaryotic cells

Answer 4

ribosomes and cell surface membrane

Question 5

describe how to make a sample for a microscope

Answer 5

1.homogenise the cells and filter
2. add to ice cold isotonic solution
3. centrifuge
4. centrifuge at higher speed

Question 6

outline the role of organelles in the production of proteins from eukaryotic cells

Answer 6

1. DNA in nucleus is code for protein
2. rough endoplasmic reticulum produce protein
3. mitochondria produce ATP for protein synthesis
4. golgi apparatus packages the protein
5. vesicles transport it

Question 7

why does the solution have to be ice cold for a microscope sample

Answer 7

to slow down enzyme activity to prevent damage to the organelles

Question 8

why does the solution have to be buffered for a microscope sample

Answer 8

to maintain the pH so enzymes are not denatured

Question 9

why does the solution have to be the same water potential for a microscope sample

Answer 9

to prevent osmosis so no lysis of organelles

Question 10

two ways nucleotides in DNA are different from ones in RNA

Answer 10

1.DNA contains thymine and RNA contains uracil
2. DNA contains deoxyribose and RNA contains ribose

Question 11

what is the function of the mitochondria

Answer 11

carry out main processes of aerobic respiration producing ATP molecules

Question 12

what is the function of the golgi apparatus?

Answer 12

to modify and transport substances like proteins

Question 13

what is the function of chloroplasts?

Answer 13

to absorb light and photosynthesise

Question 14

what is the function of the rough endoplasmic reticulum?

Answer 14

to modify and transport proteins

Question 15

what is the function of the smooth endoplasmic reticulum?

Answer 15

synthesise, store and transport lipids and carbohydrates

Question 16

what are the 4 functions of lysosomes?

Answer 16

1. help digest substances
2. releases enzymes into the cytoplasm for the cell to commit suicide(autolysis)

Question 17

what is the structure and function of ribosomes?

Answer 17

1.small made of two subunits
2. produce proteins

Question 18

what is the structure and function of cell walls?

Answer 18

1. made of cellulose
2. provide support

Question 19

what are 3 functions of a vacuole?

Answer 19

1.containing waste
2. water storage in plant cells
3. maintaining acidic internal pH

Question 20

pros and cons of electron microscopes

Answer 20

1. very high resolution because electrons have a shorter wavelength
2. very expensive

Question 21

pros and cons of light miscroscopes

Answer 21

1. easy to use
2. low resolution therefore low magnification

Question 22

what is the difference between transmission and scanning electron microscopes

Answer 22

transmission passes the be of electrons through the specimen, so the interior is visible where as scanning directs the electrons on the surface of the specimen so the exterior is visible

Question 23

how many micrometers (ųm) are in a metre

Answer 23

one million

Question 24

how many nanometres are in a metre

Answer 24

1 000 000 000

Question 25

define resolution

Answer 25

minimum distance apart that two objects can be so they appear to be separate

Question 26

4 differences between prokaryotic and eukaryotic cells

Answer 26

prokaryotic cells: 1. lack membrane bound organelles 2. smaller ribosomes 3. no nucleus as they have a single circular DNA 4. cell wall containing murein (glycoprotein)

Question 27

structure of a virus

Answer 27

1. nucleic acids 2. capsid 3. attachment protein

Question 28

why are viruses considered non living?

Answer 28

they have no organelles so are acellular and therefore non living

Question 29

describe the structure of the nucleus

Answer 29

1. contains nucleic acids 2. nuclear envelope separates nucleus from cytoplasm 3. contains nucleolus which is a dense structure 4. nucleoplasm is a substance in it 5.contains chromatin

Question 30

describe the function of the nucleus

Answer 30

1. controls heredity characteristics 2. responsible for protein synthesis 3. stores DNA and RNA 4. site of transcription 5. nucleolus produces ribosomes