Biology Recall Flashcards
What is the function of a ribosome?
Protein synthesis
Give two ways in which a plant cell is different from a bacterial cell.
The plant cell has a permanent vacuole and contains mitochondria while the bacterial cell does not.
Explain why sexual reproduction produces variety.
In sexual reproduction, fertilisation occurs meaning that there is a fusion of gametes and genetic material is mixed so that there is one copy of each chromosome from each parent.
What is the equation for photosynthesis?
carbon dioxide + water –light-energy–> glucose + oxygen
or
6CO2 + 6H2O —> C6H12O6 + 6O2
How do fossils provide evidence that species alive today have evolved from simpler organisms?
A fossil is an impression of an organism that lived a long time ago. They are shown to be simpler than present-day species but with similar features nonetheless.
There are two species of gull which cannot interbreed with each other despite having evolved from a common ancestor. Suggest an explanation for the development of these different species.
The common ancestor would have split by geographical barrier / sea. In these different areas, mutations may arise and natural selection acted on these isolated populations, the advantageous genes being passed down future generations therefore allowing the isolated populations to grow adapted to their respective areas which may have different environments, e.g. climate, predator numbers, availability of food. These differences lead to the inability for the gulls to interbreed.
What is an allele?
Alternative forms of the same gene.
What does recessive mean?
An allele only expressed if two copies are inherited.
Why does a conscious action take longer than a reflex action?
The impulse has to travel to the brain and back and therefore the pathway is a lot longer.
The IR8 variety of rice was produced by selective breeding. Explain this process
The scientists would choose traditional varieties of rice plants with large grains. They would then cross breed these rice plants and from the offspring, choose the plants with the best/desired characteristics. They would be bred repeatedly until all the plants had desired characteristics.
Describe the type of cell division that produces gametes.
When a cell divides to form gametes by meiosis, copies of genetic information are made and the cell divides twice to form four gametes, each with a single set of chromosomes. As a result, all gametes are genetically different from each other.
What is sexual reproduction?
The fusion of gametes
What is a hormone?
A chemical messenger produced by a gland.
Give three reasons why drugs must be trialled before the drugs can be used on patients.
To test for efficacy, toxicity and to find the optimum dosage.
Describe what happens at the synapse during this reflex.
Chemicals are released and diffused across the synaptic gap, transmitting impulse (information) across between neurons.
