AS Level Biology Topic 1 & 2 Qs Flashcards
Suggest why liver cells of the type shown in the diagram contain many mitochondria
Liver cells carry out more aerobic respiration to convert glucose into glycogen.
What organelle contains digestive enzymes?
Lysosomes
State two reasons why the blood smear has been stained
So it is easier to distinguish between different types of white blood cells.
Suggest one detail made visible by scanning electron OR transmission microscope.
Scanning - Surface Detail
Transmission - Mitochondria/Organelles
Suggest one stage during the secretion of a protein that requires energy
Transporting the vesicle to the cell surface membrane
3 similarities and difference of a triglyceride molecule and a phospholipid
Similarities -
Both have glycerol,
fatty acid,
Esther bonds between glycerol and fatty acid
Differences -
Triglycerides have 3 fatty acids, whereas phospholipids have 2
Phospholipids are polar, whereas Triglycerides are neutral
Phospholipid form glycolipids whereas Triglycerides bond to C atoms
Describe how you could use an emulsion test to show that seeds contain lipids.
Grind up 2cm of seed and put in a test tube,
Add 5cm of ethanol and then shake the tube thoroughly,
Then add 5cm of water and shake gently.
A white (milky) emulsion will form if seeds contain lipids.
Describe how the structure of a phospholipid is different to that of a triglyceride
Phospholipid has 2 fatty acids and a phosphate group
Triglyceride has 3 fatty acids
Explain why the adispose layer is described as tissue
Same type of cells working together with the same function
Triglyceride properties and functions
Triglyceride can stay at right state as oily droplets at body temperature underneath the skin
Explain why triglycerides are not considered to be polymers
Not made of repeating monomers
If 2 alpha glucose are linked together, what would the products be?
Water & Sucrose
Large numbers of monomers joining together
Polymerisation
Enzyme that could reverse hydrolysis
Maltose and Water
2 molecules with the same formula but different structures
Structural isomers
Molecular formula of lactose
C12H22O11
What is a reducing sugar?
A sugar that donates electrons to another chemical
What is a “non reducing” sugar?
A sugar that cannot donate electrons therefore cannot be oxidised
Suggest why trehalose might not give a positive test for non-reducing sugars using benedicts reagent?
There are no free reducing groups to reduce Cu2+ to Cu+ due to the 1-1 glycosidic bond.
What variables go on the x or y axis?
x-axis = independent variable
y-axis = dependent variable
Identify and give functions of 3 structures found in plant cells that are absent in animal cells.
Cell wall is found in plant cells, not animal cells -
Function to provide strength and stops cell from bursting when filled with water.
Chloroplasts -
Carries out photosynthesis by absorbing light
Plasmodesma -
Connect adjacent plant cells establishing living bridges between cells.
Suggest how you use benedicts solution to compare amount of reducing sugar in 2 solutions
Compare the colour
Explain why pure glucose obtained from starch has a dextrose equivalent of 100
All glycosidic bonds are hydrolysed
Name monomer found in cellulose
Beta-glucose
Explain how cellulose gives cotton its strength
Long straight chains,
Chains side by side held together by Hydrogen Bonds
Explain why acid was not used to break down fructose
Acid will alter pH
Explain why the R of a reaction of enzymes if:
a) temperature fell
b) pH chained sustainably
(i) molecules have less kinetic energy so fewer collisions less likely for enzyme-substrate complex to form
(ii)change in ph alters the shape of the active site and denatures enzyme so substrate will no longer fit the active site
Name one biologically important polymer, other than those mentioned in the passage, which would be found in straw.
Amylose
Explain why cellulose digesting enzymes do not digest lignin
Enzymes have a complimentary shape for its substrate so lignin would not fit active site
