Cell structure
Which organelle functions as the site of aerobic respiration?
Mitochondria
State the feature of the cell membrane that means that only certain molecules can enter and leave living cells.
Selectively permeable
What term describes the shape of the DNA molecule?
Double (stranded) Helix
Name the subunits of protein molecules
Amino acids
A student investigated the effect of temperature on the rate of an enzyme-controlled reaction. At 10°C, the mass of product formed was 0.4g. At 30°C, the mass of product formed was 3.2g. Calculate how many times greater the mass of product formed was at 30°C compared to 10°C.
8 times greater
Describe the function of the ribosomes
Site of protein synthesis
Describe the process of diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration/ down the concentration gradient
Describe what is meant by 'complementary base pairings' in DNA
Adenine pairs with Thymine AND Cytosine pairs with Guanine
What is a 'gene'?
A section of DNA that codes for a protein
During a field study, students used a pitfall trap to sample leaf litter organisms. They collected 120 beetles, 80 spiders, and 40 earwigs. Calculate the simplest whole-number ratio of beetles to spiders.
3 : 2
Name three structures present in a fungal cell but not a bacterial cell
Nucleus
Mitochondria
Vacuole
Describe the process of active transport
Movement of molecules from an area of low concentration to high concentration/ against the concentration gradient
AND using/ requiring energy
Describe how the two strands of DNA are held together
By (hydrogen bonds between) the complementary base pairs
State where the following stages of protein synthesis occur within a cell:
a) Amino acids are joined together
b) mRNA is synthesised
a) Ribosome
b) Nucleus
A microscope field of view has a diameter of 2.4mm. A student observes that a chain of 12 yeast cells spans exactly across the center of the field of view. Calculate the average diameter of a yeast cell in micrometres (um).
200 micrometres
Describe the difference between the cell wall of a plant cell and the cell wall of a bacterial cell
Plant cell walls are made of CELLULOSE, bacterial cell walls are made of other substances
On the board there is an image of a plant cell placed in a solution.
Draw a labelled diagram to show the change in appearance of this cell after one hour AND state the term that describes the appearance of this cell.
Plasmolysed - 100
Vacuole drawn and labelled - 100
Cell membrane drawn and labelled -100
Cell wall drawn and labelled - 100
A gene contains 2000 DNA bases. 15% of these bases are Thymine. Calculate the number of Cytosine bases in this gene.
700 Cytosine bases
Describe how the gene encoding the hormone insulin would differ from the gene encoding for the enzyme Amylase
The order/sequence of DNA bases would be different
An ecosystem study tracked the number of mature oak trees in a woodland area. Due to disease, the number of healthy trees fell from 80 to 76 over the course of a year.
Calculate the percentage decrease in healthy oak trees.
5%
Describe how DNA is organised in bacterial cells
- A circular chromosome
- Plasmids
On the board there are images of three cubes of potato tissue placed in three different solutions.
Which cube of potato will likely show the greatest change in mass after 1 hour.
Give a reason for your answer
Potato :
Reason: Biggest/ largest concentration gradient
Describe the role of messenger RNA (mRNA) in the synthesis of a protein
Carries/ transports a complementary copy of the genetic code/ order of the DNA bases from the nucleus to the ribosomes where the protein is made
An experiment investigates how toxic a new weedkiller chemical is to pond snails. A tank is set up with 5 liters of pond water, 10 pond snails, and 10cm3 of the chemical weedkiller. Describe the control setup required to show that the weedkiller is what affects the snails.
Exactly the same experiment set up but replace the weedkiller with the same volume of water