Unit 2 - Cell Biology

Question 1

why do we use buffer solution in cell franctionatio

Answer 1

to keep the pH constant because if pH changes then enzymes in the cell could denature

Question 2

why do we use cold temperatures in cell fractionation

Answer 2

• to slow down enzymic activity - prevent destructive enxymes from damaging organelles

Question 3

what does cell fractionation mean

Answer 3

the seperation of all the different organelles

Question 4

what is meant by the term resolution

Answer 4

the minimum distance between 2 objects where they can still be seen as 2 seperate objects

Question 5

whats an advantage and a disadvantage to a light microscope

Answer 5

we can look at living cells but it has a poor resolution

Question 6

how many micrometres is 1mm

Answer 6

1000

Question 7

whats an advantage and disadvantage to electron microscopes

Answer 7

• they have better resolution than light microscopes
• you cannot view living specimens

Question 8

whats an advantage and disadvantage to a TEM

Answer 8

• high resolution
• 2d image

Question 9

whats an advantage and disadvantage to a SEM

Answer 9

• 3d image
• lower resolution

Question 10

give 3 examples of eukaryotic organisms

Answer 10

animals
plants
fungi

Question 11

give 2 examples of prokaryotic organisms

Answer 11

bacteria
archea

Question 12

what are 3 key features to eurkaryotic cells

Answer 12

• they have their DNA in a membrane bound nucleus
• their DNA is tightly wrapped around histone proteins
• membrane bound organelles are present

Question 13

what is the role of ribosomes

Answer 13

site of protein synthesis

Question 14

name 2 polysaccharides which make up cell walls in plants and fungi

Answer 14

cellulose for plant
chitin for fungal

Question 15

what are 3 major differences between prokaryotic and eukaryotic cells

Answer 15

• prokaryotic cells are much smaller
• DNA is free flowing in cytoplasm in prokaryotic cells
• ribosomes in prokaryotic cells are smaller than in eurkayotic

Question 16

what is the cell wall made of in prokaryotic cells

Answer 16

peptidoglycan (murein)

Question 17

what is the role of pili in prokaryotic cells

Answer 17

means bacteria cells can attach onto surfaces or other bacteria cells

Question 18

when can viruses reproduce

Answer 18

when inside a host cell

Question 19

how does a virus reproduce

Answer 19

by using the host cells enzymes to make copies of itself

Question 20

what does acellular mean

Answer 20

not based on cells

Question 21

what are 3 roles of proteins in cells

Answer 21

• they make up enzymes
• they make up structural proteins
  -they transport molecules like haemoglobin

Question 22

what is the process of transcription

Answer 22

when the gene is converted into mRNA in the nucleus

Question 23

what is the process of translation

Answer 23

when a ribosome reads the info in mRNA and synthesises the protein molecule

Question 24

what is the function of nuclear pores

Answer 24

to allow molecules to enter and leave the nucleus

Question 25

what is the role of vesicels

Answer 25

transport polypeptides to from the RER to the golgi

Question 26

what is the role of the smooth ER

Answer 26

make and store both lipids and carbohydrates

Question 27

what is the role of the rough ER

Answer 27

the ribosomes on the surface sythesise proteins the proteins then move through RER where theyre modified

Question 28

give an example of a modification the RER can make

Answer 28

a carbohydrate molecule can be attatched to the protein to make a glycoprotein

Question 29

what is the role of the golgi apparatus

Answer 29

involved in the process and packaging of proteins

Question 30

what are the 2 roles of lysosomes

Answer 30

- they contain protease which is a digestive enzyme - used to destroy organelles which are damaged or no longer work

Question 31

what does protease do

Answer 31

digests larger molecules into smaller soluble molecules

Question 32

what is the role of mitochondira

Answer 32

site of aerobic respiration which produes ATP (energy)

Question 33

where could you find a large number of mitochondria

Answer 33

muscles as they contract which require a lot of energy

Question 34

what is the role of chloroplasts

Answer 34

site of photosynthesis

Question 35

what is the equation for photosynthesis

Answer 35

CO2 + water = oxygen + glucose

Question 36

what are 2 functions of cell walls

Answer 36

- provide strength to the cell - gives cells rigidity and contribute to the shape

Question 37

what is the role of a vacuole

Answer 37

- removal of waste materials

Question 38

whats the difference between animal and plant vacuoles

Answer 38

animal vacuoles are temporary plant vacuoles are permanent