Mock Feedback Flashcards
Describe the structure of glycogen
- Polysaccharide/polymer of alpha glucose
- Joined by glycosidic bonds
Suggest how glycogen acts as a source of energy
- Hydrolysed to glucose
- Glucose used in respiration
Suggest and explain two ways the cell surface membranes of the cells lining the uterus may be adapted to allow rapid transport of nutrients
- Large number of protein carriers for active transport
- Large number of protein channels for facilitated diffusion
- Large number of protein (carriers/channels) for co transport
Describe two structural features of insoluble fibrous proteins
- Long straight chains of polypeptides
- High proportion of non-polar/small/ hydrophobic amino acids
- Parallel chains held with hydrogen bonds
Describe the secondary structure of a polypeptide
- Beta pleated/ alpha helix
- Held together by hydrogen bonds between amine and carboxylate group
Explain one precaution that should be taken when using a potometer
- Keep screw clip closed
- Prevents entry of water whilst measuring
Describe how new xylem cells are produced
- Produced in meristems
- Through differentiation from stem cells
Explain the role of the heart in the formation of tissue fluid
- Contraction of left ventricle produces high hydrostatic pressure
- This forces water out of blood capillaries
Suggest how a blockage in the lymphatic system could cause lymphoedema
Excess tissue fluid builds up
Explain how the structure of phospholipid molecules allows for the formation of plasma membranes
- Phosphate head is hydrophilic
- Fatty acid tails are hydrophobic
- Heads orientate towards water / tails orientate towards other fatty acids
Suggest and explain why a low pH might cause the red pigment to leak out the beetroot cells
- Denatures membrane proteins
- Therefore membrane permeability is increased
Explain why the velocity of blood flow in the large arteries is slower than the velocity of blood flow in the aorta
- Blood in aorta is under higher pressure because has just even pumped out of left ventricle
- Aorta branches into many arteries
- The friction between blood and vessel slows the velocity down
Explain why the total surface area of the capillaries needs to be so high
- More plasma is able to leave
- Results in higher rate of diffusion
Describe how a test for reducing sugars is carried out
- Use Benedict’s reagent and heat
- Red/ green/ orange ppt
Describe how the process of meiosis results in haploid cells
- DNA replication
- Two divisions
- Separates homologous chromosomes
- Separates sister chromatids
- Produces 4 haploid cells
Give two differences between genetic diversity and species richness
- Genetic diversity considers one species whereas species richness considers number of species
- Genetic diversity considers alleles whereas species richness is within a habitat
Describe how species are grouped in a phylogenetic classification system
1.hierarchy with no overlapping
2. Grouped according to evolutionary relationships
Describe the structure of DNA and the structure of a chromosome
- Polymer of nucleotides
- Nucleotide consists of deoxyribose, phosphate and nitrogenous base
- Strands held by hydrogen bonds
- Hydrogen bonds between adenine,thymine and cytosine , guanine
- DNA is associated with histones
- Chromosome consists of two chromatids joined at a centromere
Mutation can result in an increase in genetic variation within a species. Describe and explain the other processes that result in increases in genetic variation within a species
- Independent segregation of homologous chromosomes
- Crossing over between homologous chromosomes
- Random fertilisation of gametes
- Produces new combinations of alleles
Describe and explain a difference in the structure of pre-mRNA and mRNA
- mRNA fewer nucleotides
- Because of splicing
Name two structures on a virus
- Attachment protein
- Capsid
Describe how HIV is replicated
- Attachment proteins attach to receptors on helper T cell
- Nucleic acid enters cell
- Reverse transcriptase converts RNA to DNA
- Viral protein produced
- Virus assembled and released from cell
Describe the role of lysosomes in digesting bacteria
- Fuse with vesicle
- Release hydrolytic enzymes
Describe how a gene is a code for the production of a polypeptide
- Base sequence
- In triplets
- Determines order of amino acid sequence
Describe how the structure of glycogen is related to its function
- Branched so compact
- Polymer of glucose so easily hydrolysed
- Branched so more ends for faster hydrolysis
- Glucose polymer so provides respiratory substrate for energy
- Insoluble so does not affect water potential
Explain how water from tissue fluid is returned to the circulatory system
- Proteins remain
- Creates water potential gradient/reduces water potential
- Water moves to blood by osmosis
- Returns to blood by lymphatic system
