Paper 1 Questions Flashcards
Which features of phospholipids give them their amphipathic properties?
Hydrophilic phosphate groups and hydrophobic fatty acids
How do mitochondria and chloroplasts provide evidence for the endosymbiotic theory?
They have double membranes
Which molecule regulates the fluidity of cell membranes
Cholesterol
What feature of arteries is most important in maintaining sufficiently high blood pressure?
Elastic fibres in the wall.
A variety of Pelagornium has yellow leaves. When plants of this variety crossed, the resulting seeds produced green, yellow, and white seedlings in the ratio 1:2:1. If plants with yellow leaves are crossed with plants with green leaves, what would the expected ratio of phenotypes in the offspring be?
Green: 2 Yellow: 2 White: 0
What is the same in all parts of homologous chromosomes?
Sequence of genes.
What does the Rf value in thin layer chromatography represent?
The ratio of distances travelled by the pigment and solvent fronts.
What is the role of the protein, collagen?
Most common structural protein in mammals.
Which compound is a waste product of anaerobic respiration in humans?
Lactate
Lactose can be removed from milk by passing the milk through a column of alginate beads to which the immobilised lactase is bound. What is an advantage of immobilising the enzyme?
It allows the product to be separated easily from the enzyme.
Testosterone is a hormone that is important for male reproductive development. To which group of compounds does testosterone belong?
Lipids
An organism has the following characteristics:
- Single opening for ingestion and egestion.
- Radial Symmetry
- Tentacles with stinging cells.
Cnidaria
Which genotype would be seen in a person suffering from Huntington’s disease?
Hh
What helps make the genome of each human unique?
Orientation of pairs of homologous chromosomes during meiosis.
Crossing over during meiosis.
Fusion of gametes from two different parents.
What is PCR used for?
Amplify small amounts of DNA.
What is the same in all parts of homologous chromosomes?
Sequences of genes.
What is the benefit to living organisms that water has a high specific heat capacity?
Aquatic environments do not have a great fluctuation in their temperature.
What features of arteries is most important in maintaining sufficiently high blood pressures?
Elastic fibres in the wall.
What is a feature of phagocytic white blood cells?
Form part of non-specific immunity.
How do neonicotinoid pesticides cause paralysis and death in insects?
- Acetylcholine receptors are blocked.
- Cholinesterase fails to break down the pesticides.
A female is overweight. feels cold and tired and often fails to ovulate during the menstrual cycle. Which two hormones are probably secretes at insufficient levels?
LH and thyroxin.
When the left ventricle is relaxed, what is the state of the valves?
Atrioventricular valve: Open
Semilunar valve: Closed
Which statement provides evidence for endosymbiosis?
Eukaryotic mitochondria and chloroplasts have their own circular DNA.
Which of the following are features of prokaryotes and eukaryotes?
-70s ribosomes: prokaryotes
-80s ribosomes: eukaryotes
-Naked DNA: prokaryote
DNA associated with proteins: eukaryote
What route is used to export proteins from the cell?
Rough endoplasmic reticulum - Golgi apparatus - Plasma membrane
Which organisms has DNA located in three organelles?
A fern
Which of the following will contribute to the cell theory?
- Living organisms are composed of cells.
- All cells come from pre-existing cells by mitosis.
- Cells are the smallest units of life.
Which process is possible due to the fluidity of cell membranes?
Endocytosis
Which organelle is involved in generating vesicles destined for the cell membrane?
Golgi apparatus
Which structure found in eukaryotes has a single membrane?
Lysosome
Which sequence shows increasing relative size?
Membrane thickness - Virus - Bacterium
In which parts of the digestive system are most water and glucose absorbed?
Water: Large intestine
Glucose: Small intestine
Which organelle provides evidence that eukaryotic cells originated when prokaryotes engulfed small free-living prokaryotes?
Chloroplast
What is the principal mode of division for the prokaryote Escherichia coli?
Binary Fission
Which features of the alveoli adapt them to gaseous exchange?
- Single layer of cells.
- Film of moisture.
- Dense network of capillaries.
Where do motor neurons conduct impulses from and to?
From the central nervous system to effectors.
Which feature of striated muscle cells allows them to be considered as a possible exception to cell theory?
They contain more than one nucleus.
Where can 70s ribosomes be found?
In prokaryotic cells.
Which is the correct statement concerning HIV and AIDS?
All AIDS patients have HIV.
Which of the following is correct for lipase?
Substrate: Triglycerides
Source: Pancreas
pH - 7
What is the body’s response to low blood glucose levels?
Alpha cells in the pancreas secrete glucagon.
What causes the atrioventricular valve to close during a heartbeat?
Pressure in the atria is lower than the ventricles.
What happens to the external and internal intercostal muscles and diaphragm when inhaling?
External intercostal muscles: Contract
Internal intercoastal muscles: Relax
Diaphragm: Contracts
Why is sweat a good coolant for the body?
Breaking H bonds between water molecules in sweat requires energy from body heat.
Which gas produces most of the bubbles in bread dough?
Carbon dioxide
What distinguishes prokaryotic cells and eukaryotic cells?
Prokaryotic cells: Cell structure not compartmentalized.
Eukaryotic cells: Cell structure compartmentalized.
What event occurs only in meiosis?
Random separation of homologous chromosomes.
How can molluscs and Platyhelminthes be distinguished?
Molluscs have a mouth and an anus but platyhelminthes do not.
Which process promotes variation in a population?
Mutation
Which discovery was an indication that the heart pumps blood to the body through arteries?
The heart swelled up when the arteries were not tied in an animal experiment.
Which is a valid comparison between arteries and veins?
Arteries carries blood flows at high pressure.
Veins carries blood flows at low pressure.
Which statement is true for the antibiotic penicillin?
Viruses lack metabolism and penicillin has no effect on them.
How can knowledge about the pineal gland functions be applied?
To restore sleep time by the use of melatonin.
How does potassium move across the membrane of a neuron during repolarization?
B. Facilitated Diffusion
What feature of carbon makes it most suitable as a basis of life?
B. Its bonding properties