Biology Paper 2 Questions Flashcards
What characteristics are controlled by one gene?
Fur colour in mice and red- green colour blindness in humans
What is an allele?
A variation of a gene
What is a dominant allele?
An allele that is always expressed, even if only one copy is present.
What is a recessive allele?
An allele that is only expressed if there are two copies present
What is phenotype?
The characteristic that presents because of the genotype
Define homozygous
The organism has two of the same alleles for the trait
Define heterozygous
The organism has two different alleles for the trait
What is polydactyly?
A disorder that causes extra fingers or toes. It is caused by a dominant allele
What is cystic fibrosis?
A disorder of the cell membranes that is caused by a recessive allele
How many chromosomes does a normal body cell contain?
23 pairs
What are producers?
Photosynthetic organisms that are the producers of biomass. They are the start of a food chain
What are examples of producers?
A green plant or algae
How can feeding relationships within a community be represented?
Food chains
What are primary consumers?
Organisms that eat producers
What are secondary consumers?
Organisms that eat primary consumers
What are consumers?
An animal that eats to gain energy
What are predators?
Consumers that kill and eat other animals
What are prey?
Consumers that are hunted and killed by other animals
Why is it important that materials are cycled?
To provide the building blocks for future organisms
What is the carbon cycle?
It is the way that carbon is returned from organisms to the atmosphere as carbon dioxide to then be used by plants in photosynthesis
What are some of the processes that cycle carbon?
Photosynthesis, respiration, combustion
What is the word equation for photosynthesis?
Carbon dioxide + water ——> glucose + oxygen
What is the word equation for respiration?
Glucose + oxygen ——> carbon dioxide + water
What is the word equation for combustion?
Fuel + oxygen ——> carbon dioxide + water