The Powerhouse of the Cell
What molecule is the main energy currency of the cell?
ATP
What molecules on a pathogen can be recognised by the immune system?
Antigens
What type of immunity develops when a person produces antibodies after being infected by a pathogen?
Natural Active immunity.
What term describes the passing of genetic information from parents to offspring?
Inheritance (heredity).
What is the term for the preserved remains or traces of organisms that lived in the past?
Fossils.
In which organelle, and where in that orgnaelle, does the Krebs cycle occur in eukaryotic cells?
Mitochondrion (mitochondrial matrix)
Give one example of a physical or chemical barrier that forms the body's first line of defence.
Any one: intact skin, mucus, cilia, stomach acid, tears containing antimicrobial enzymes.
Name one method used to reduce the spread of infectious diseases through a population.
Any one: vaccination, handwashing, isolation, quarantine, sterilisation or wearing a mask.
What is the source of new alleles that can introduce genetic variation into a population?
Mutation
Which type of evidence compares similarities in DNA sequences to determine how closely related two species are?
Molecular evidence (DNA comparison).
What is the name of the process that breaks glucose into two pyruvate molecules?
Glycolysis
Which category of white blood cell engulfs and digests pathogens as part of the second line of defence?
Phagocyte (e.g. macrophage or neutrophil).
Why is it advantageous for people to develop immunity through vaccines rather than direct contact with pathogens?
They do not get sick from vaccines while direct pathogen contact can cause serious or deadly illness.
They do not get symptomatic and will not pass the disease on to others.
What is the term for the random change in allele frequencies in a population due to chance events?
Genetic drift.
What does it suggest when two species share a large number of homologous structures?
They share a common ancestor.
Where in the mitochondrion does the electron transport chain occur?
Inner mitochondrial membrane
What is the function of antibodies in the third line of defence?
They bind to specific antigens on pathogens, helping neutralise them or mark them for destruction.
What is the difference between active immunity and passive immunity?
Active: the person's immune system produces its own antibodies and memory cells.
Passive: antibodies are received from another source; protection is temporary.
According to the biological species concept, what two key features define organisms as being the same species?
They can interbreed and produce viable, fertile offspring.
What is the name of the method used to determine the age of once-living material by measuring the decay of carbon-14?
Radiocarbon dating (carbon dating).
Explain why oxygen is required for aerobic cellular respiration, even though it is not directly used in glycolysis.
Final electron acceptor: Oxygen accepts electrons at the end of the electron transport chain. Effect: This allows electron transport and oxidative phosphorylation to continue, supporting ATP production.
A pathogen enters the body through a cut. Describe how a lymph node can help initiate an immune response against this pathogen.
Pathogens or their antigens are transported in lymph to lymph nodes.
Lymphocytes in the lymph node recognise specific antigens.
The matching lymphocytes become activated.
Activated lymphocytes multiply and contribute to a specific immune response.
How can monoclonal antibodies be used to treat cancer? Give two ways they can help.
Bind to specific antigens on cancer cells.
Mark cancer cells for destruction by the immune system.
Block signals that stimulate cancer cell growth.
Deliver a toxic substance or treatment directly to cancer cells.
Farmers selectively breed cattle that produce the most milk. Explain how this could increase milk production in future generations.
Cattle with heritable traits for high milk production are selected for breeding.
They pass these alleles to their offspring.
The frequency of alleles associated with high milk production increases over generations.
Name two anatomical changes that occurred during human evolution as early hominins became adapted to bipedalism.
Foramen magnum positioned further underneath the skull.
S-shaped spine.
Shorter, broader pelvis.
Femur angled inwards towards the knee.
Arched feet.