Cell structure methodology exam paper Flashcards
how could scientist use temporary mounts of leaves to determine the mean number of chloroplast in mesophyll cells?
1) select a large number of cells
2) Count the number of chloroplast
3) divide the number of chloroplast by the number of cells
name two structures in a eukaryotic cell that cannot be identified using a light microscope
1) mitochondria
2) ribosomes
explain one difference in structure of starch molecules and Celulose molecules
1) starch is formed by alpha glucose molecules whereas cellulose is formed from beta glucose molecules
2) The position of the hydroxyl group on carbon atom 1 is inverted (cellulose)
explain one way in which starch molecules are adapted for their function in plant cells
Starch molecules are insoluble this means water potential is affected via osmosis and it doesn’t dissolve
Explain how cellulose molecules are adapted for their function in plant cells
they have hydrogen that links the long chains of beta glucose molecules in order to strengthen the structure this helps maintain the shape of the cell wall by keeping it turgid
how do you know when a transmission electron microscope is used to produce an image
1) high resolution
2) you can see internal structures e.g mitochondria
what is the function of the rough endoplasmic reticulum
Protein synthesis
what is the function of the Golgi apparatus
to modify proteins
What is the function of mitochondria
Aerobic respiration
describe the arrangement of phospholipids in plasma membrane
1) Hydro phobic phosphate heads to water
2) hydrophilic fatty acid tails to water
Describe have a rough endoplasmic reticulum is involved in the production of enzymes
The rough endoplasmic reticulum are studded with ribosomes in order to produce proteins - enzymes are proteins
Describe have a Golgi apparatus is involved in the secretion of enzymes
The Golgi apparatus modifies proteins and packages them into vesicles that transport them to cell surfaces
give two structures of bacterial cell may have a white blood cell does not
1) Cell wall
2) Slime layer (capsule)
Name one organelle that you would expect to find in large numbers in a mucus secreting cell
mitochondria
What is the function of the mitochondria
1) Aerobic respiration
2) produces ATP for energy
True or false?
starch and cellulose can be found in plant cells
True
True or false?
glycogen can be found in plant cells
false
True or false?
starch, Cellulose and glycogen all contain glycocidic bonds
True
True or false?
starch, cellulose and glycogen all contain alpha glucose molecules
false
only starch and glycogen, cellulose is composed of beta glucose molecules
give one feature of starch that enables it to act as a storage substance
it is compact. it is coiled into a helical shape so more can be stored
describe the function of chloroplasts
traps and absorbs light for photosynthesis
name two structures that are present in plant cells but I’m not present in animal cells
1) cell wall
2) chloroplast
why is using starch as a carbohydrate store an advantage
it is insoluble. this means it won’t dissolve in water and water potential isn’t affected. 
name two structures present in an epithelial cells that are not present in bacteria
1) rough endoplasmic reticulum
2) Golgi apparatus
give one advantage of using transmission electron microscope
It has high resolution
Give one advantage of using an SEM rather than a TEM
3-D images
What type of bond joins amino acids together in a polypeptide
Peptide bonds
describe the passage of amino acids from the cytoplasm until it is secreted from the cell as a protein
1) In the cytoplasm
2) Through the rough endoplasmic reticulum
3) through the Golgi apparatus
4) Out the cell
there are lots of mitochondria in cells from the pancreas explain why
it is the site of aerobic respiration and it produces ATP for energy
When carrying out cell fractionation scientist homogeneous tissue, Explain why
To break up cells
When carrying out cell fractionation scientist filtered the resulting suspension
to remove any debris or foreign things
When carrying out cell fractionation scientist kept the suspension ice cold, explain why
to reduce enzyme activity this prevents cells from denaturing
When carrying out cell fractionation scientist used an isotonic solution, explain why 
so osmosis doesn’t affect water potential this means cells aren’t at risk of bursting or shrinking
Explain two ways fatty acids are important for the formation of new cells
1) Fatty acids are used to make phospholipid (phospholipids form membranes) the more phospholipids made, the more membranes are formed.
2) fatty acids are respired for energy this energy can be used for cell production
there are a large number of mitochondria in epithelial cells from the small intestine, explain how mitochondria help to absorb the products of digestion
ATP production
Name the process in which cells become adapted for different functions
cell specialisation or cell differentiation
at what speed would you expect to find the mitochondria at the bottom of a test tube 
A medium speed
When isolating mitochondria from liver cells they broke cells open in an ice cold isotonic solution explain why
1) ice cold: to reduce enzyme activity so the cell doesn’t denature
2) isotonic: to prevent osmosis from causing cells to burst or shrink (so water potential isn’t affected)
