A
What is the function of the nucleolus?
A The formation and breakdown of the nuclear envelope.
B The formation of rough endoplasmic reticulum.
C The synthesis of ribosomal proteins.
D The synthesis of rRNA.
D The synthesis of rRNA.
Which statements about the effect of all enzyme inhibitors are correct?1-change the shape of the active site;2-denature the enzyme;3-reduce the rate of the enzyme-catalysed reaction
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 3 only
D 3 only
Which cells become memory cells in the immune response?
1-B-lymphocytes; 2-T-lymphocytes; 3-phagocytes
A 1, 2 and 3
B 1 and 2 only
C 1 only
D 2 only
B 1 and 2 only
Which soil would have the smallest number of denitrifying bacteria?
A compressed agricultural soil
B poorly drained forest soil
C water-logged clay soil
D well-aerated garden soil
D well-aerated garden soil
9 In an ecosystem, at which stage is most energy lost?
A sunlight → trophic level 1
B trophic level 1 → trophic level 2
C trophic level 2 → trophic level 3
D trophic level 3 → trophic level 4
A sunlight → trophic level 1
Which adaptation would increase active transport of carbohydrates from a plant cell?
A areas where the cell wall is thin
B increased permeability of the cell wall
C large surface area of the cell surface membrane
D selective permeability of the vacuole membrane
C large surface area of the cell surface membrane
What is the order of size of cell structures?
largest → →→→→→→→→→→→smallest
A centriolesribosomes lysosomes nucleoli
B lysosomes nucleoli centrioles ribosomes
C nucleoli lysosomes centrioles ribosomes
D nucleoli centrioles ribosomes lysosomes
C nucleoli lysosomes centrioles ribosomes
In unsaturated lipid molecules, where are double bonds located?
A between fatty acids and glycerol
B within fatty acids and within glycerol
C within fatty acids only
D within glycerol only
C within fatty acids only
11 Which level of organisation of a haemoglobin molecule is coded by a DNA molecule?
A primary structure
B secondary structure
C tertiary structure
D quaternary structure
A primary structure
The statements are about enzymes.
1-They are globular proteins. 2-They are formed in the smooth endoplasmic reticulum. 3-They are only found attached to plasma membranes in the cell. 4-They can be inhibited by competitive inhibitors.
Which statements are correct for all enzymes?
A 1 and 4 only
B 2 and 4 only
C 1, 2 and 3 only
D 1, 2, 3 and 4
A 1 and 4 only
The fluidity of the cell surface membrane can be changed by a number of factors.
As the fluidity of cell surface membranes decreases, which process would be least changed?
A active transport
B diffusion
C endocytosis
D osmosis
A active transport
Which molecules in cell surface membranes contribute to cell recognition?
A cholesterol, glycolipids, phospholipids
B cholesterol, phospholipids, proteins
C glycolipids, glycoproteins, proteins
D phospholipids, glycoproteins, proteins
C glycolipids, glycoproteins, proteins
Which is correct for facilitated diffusion and active transport?
A both depend on the solubility of the transported molecule in the lipid bilayer
B both increase as the concentration of the transported molecule increases
C both require the use of ATP
D both require the use of membrane proteins
D both require the use of membrane proteins
Which features increase the efficiency of ion uptake by a root hair cell?
1-many mitochondria in the cell 2-high concentration of ions in the vacuole 3-protein carriers in the cell surface membrane
A 1, 2 and 3
B 1 and 3 only
C 2 and 3 only
D 1 only
B 1 and 3 only
Which processes occur by mitosis?
1-cloning of plasma cells;2-gamete production;3-replacing damaged cells
A 1, 2 and 3
B 1 and 3 only
C 2 only
D 3 only
B 1 and 3 only
Which processes are involved in transpiration?
1-the diffusion of water vapour from stomata; 2-the mass flow of water through the xylem; 3-the evaporation of water from the surface of mesophyll cells; 4-the evaporation of water vapour from air spaces
A 1, 2 and 3
B 2, 3 and 4
C 1 and 3 only
D 1 and 4
A 1, 2 and 3
What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element?
A moving sucrose into the sieve tube element
B removing protons out of the cytoplasm of the companion cell
C removing protons from the sieve tube element
D taking up sucrose into the cytoplasm of the companion cell
B removing protons out of the cytoplasm of the companion cell
Which features allow an artery to resist changes in the pressure of blood flowing through it?
1-smooth endothelium; 2-thick elastic layer in the artery wall; 3-thick layer of muscle in the artery wall
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
D 2 and 3 only
A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again.
Which microorganisms will increase by the time the rotation starts again?
1-denitrifying bacteria; 2-nitrifying bacteria; 3-nitrogen-fixing bacteria; 4-decomposing bacteria
A 1, 2 and 3
B 1, 2 and 4
C 1, 3 and 4
D 2, 3 and 4
D 2, 3 and 4
What are correct locations of ribosomes in the typical eukaryotic cell?
1-free in the cytoplasm; 2-attached to the outside of the endoplasmic reticulum; 3-attached to the inside of the endoplasmic reticulum
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
B 1 and 2 only
Two species of animal are found in the same area of forest and grassland. In the spring and summer they eat the same plant food. However, in the autumn and winter one eats nuts in the forest and the other eats roots on the grassland. Both species are preyed upon by the same predator. Numbers of root-eating animals are reduced most by this, but they recover faster since they reproduce faster.
What can be concluded about these two species of animals?
1-They are part of the same community. 2-They are at different trophic levels. 3-They occupy different habitats. 4-They have different niches.
A 1, 2 and 4
B 2, 3 and 4
C 1 and 2 only
D 1 and 4 only
D 1 and 4 only
Visking tubing is an artificial partially permeable membrane used to demonstrate diffusion. Glucose molecules can pass through the pores in the membrane which are approximately 2.4 nm in diameter.
Which of the following could pass through the pores? 1 bacteria 2 haemoglobin 3 ribosomes 4 glycogen
A 1 and 3
B 2 and 4
C 2 only
D none of the above
D none of the above
Chitin is a polysaccharide consisting of long straight chains of the monosaccharide acetylglucosamine, linked by 1,4 glycosidic bonds.
Acetylglucosamine is similar in structure to glucose, but contains nitrogen, allowing hydrogen bonds to form between adjacent chains of chitin when they lie parallel to each other.
Which polysaccharide is most similar in structure to chitin?
A amylopectin
B amylose
C cellulose
D glycogen
C cellulose
Influenza virus has an enzyme called neuraminidase which breaks down glycoproteins in the membrane of the cell that the virus will infect. The glycoprotein binds to the active site of neuraminidase by induced fit.
Which statements about the induced fit hypothesis of enzyme action are correct?
1 The active site must have a complementary shape to the substrate for them to bind together. 2 This enzyme is less likely to be affected by non-competitive inhibitors than an enzyme working by the lock and key mechanism. 3 The substrate is converted to product by specific R-groups in the active site just like the lock and key mechanism.
A 1 and 2
B 2 and 3
C 2 only
D 3 only
D 3 only
A student carried out experiments to investigate the effect of enzyme concentration on the rate of hydrolysis (break down) of protein in milk. When the enzyme and milk were mixed, the protein was hydrolysed and the mixture changed from cloudy to clear. The student investigated five different enzyme concentrations and recorded the time taken to reach the end-point for each.
What is an appropriate control for this investigation?
A Carrying out a further experiment where the enzyme solution is replaced with water.
B Carrying out each experiment in a thermostatically regulated water-bath at 35 °C.
C Performing three repeat experiments for each of the five enzyme concentrations.
D Using the same volume of enzyme solution for each of the five experiments.
A Carrying out a further experiment where the enzyme solution is replaced with water.