Mock Flashcards
Give the three structural features found in all virus particles and describe the function
of one of these features.
1) attachment proteins
-attach to receptors on helper T-cells
2) capsid
3) lipid envelope
Explain why viruses are described as acellular and non-living
Viruses are acellular because they lack a cell wall and cell membrane
They are Inactive outside a host and can only reproduce when they are In a host. Viruses cannot carry out respiration
Give one reason why antibiotics are not effective against viruses.
Antibiotics breakdown the Murein cell wall and cell membrane In bacterica, which are both absent In Viruses
describe three ways the structure of chitin is similar to the structure of cellulose.
Chitin makes up cell walls in fungi
1) Cellulose and Chitin are both long straight chains of Beta glucose
2) They are both joined by glycosidic bonds (inverted 180°) and hydrogen bonds between the monomers.
3) The hydroxyl group (-OH) Is above carbon because they have a beta glucose.
They both can form macrofibrils
Chitin keeps the tracheae open in the tracheal system of gas exchange in an insect.
Gas exchange does not occur in the tracheae.
Explain the importance of one adaptation of the gas exchange surface in the tracheal system of an insect.
Trachea provides tubes full of air so there will be a faster rate of oxygen diffusion
Into the Insects tissue
Tracheoles are highly branched and have thin walls to provide a short diffusion distance to cells.
Lignin (Adhesion of H2O) is a polymer found in the walls of xylem vessels in plants. Lignin keeps the
xylem vessel open as a continuous tube.
Explain the importance of the xylem being kept open as a continuous tube
This will ensure water Is pulled to the leaves as a continuous column is provided In the xylem.
The water will be transported up the Xylem under high pressure so needs be free from obstructions which will create a water potential gradient as water is lost at the Leaves by evaporation
Describe two functions of the Golgi apparatus in a eukaryotic cell.
1) packages and modifies proteins by adding carbohydrates, making glycoproteins
1) responsible for making lysosomes
In Africa today, most of the human population are resistant to malaria caused by
P. vivax.
Use your knowledge of natural selection to explain why this resistance is so common in Africa.
resistance to malaria caused by a mutation, this will lead to variation.
This Is an example of directional selection.
People resistant to p.Vivax would create new alleles, those with resistant alleles will reproduce and pass alleles onto offspring
Over time the allele frequency will increase In Africa where p. vivax Is common so more people will be resistant
Explain why the damage to the cells lining the ileum reduces absorption of the products of digestion and why this reduces absorption of water.
damage occurs to the Microvilli, which results In a reduced surface area so less/no products are absorbed into the ileum
As little glucose and proteins can be absorbed by facillitated diffusien and fewer co-transport protein along with sodium ions.
Proteins are large they remain In the ileum lowering the water potential prevents a
Water potential gradient so less waters absorbed by osmosis
suggest how this passive immunity would work and which patients should be offered this anti-toxin antibody.
Anti-toxin Antibody would be
injected in patients with c.difficile (application from question)
Infection and Diarrhoea.
The anti-toxin Antibodys bind to the toxins causing diarrhoea causing their destruction preventing diarrhoea taking place
This will help increase the mean anti-toxin concentration, reducing the effect of diarrhoea.
Describe how the anti-toxin antibody (protein) would be digested
Endopeptidases hydrolyse the peptide bonds In the middle of the protein, Increasing the
number of ends.
Exopeptidases act at the end of a polypeptide
Dipeptidases hydrolyse the peptide bonds between two Amino Acids producing single
Amino Acids.
A student investigated the use of cinnamon oil as an antimicrobial substance.
She investigated the effect of cinnamon oil on the growth of five different bacterial cultures grown on agar plates.
The student added 100 mm3 of each bacterial culture from its glass bottle onto a separate agar plate. She spread each bacterial culture evenly over the agar using a
spreader.
Describe the aseptic techniques she should use.
wash hands with soap and
disinfect surfaces
Use sterile pipettes and syringes to transfer bacteria
place pipette and spreaders into disinfectant immediately after use.
Suggest exactly what the student added to the wells to get the positive control and
negative control results.
negative control - distilled and sterile water
Positive control - known antibiotic / bacteria
Define genome and proteome.
Genome - The complete set of genes In a organism
Proteome - The range of proteins that an organism can produce
Consider the accuracy and limitations of the early classification of bacteria using the
arrangement of flagella
Optical microscope has a higher resolution so it may be difficult to see flagella
Electron Microscope has a higher resolution so can
using a optical Microscope specimen needs to be stained and artefacts can appear on the image
