Patterns of inheritance Flashcards
1
Q
What is variation?
A
- variation arises as a result of mutations
- changes to the genetic code which are random and constantly taking place
- essential for natural selection
- and therefore evolution
2
Q
What is chlorosis?
A
- plants are gnetically coded to produce large quantaties of chlorophyll
- green pigment that is ivtal for photosynthesis
- some plants suffer from a condition known as chlorosis
- when the leaves look pale or yellow
- cells do not prodcing the normal amount of chlorophull
- the disease limits the plants ability to make food by photosyntheses
3
Q
WHat causes chlorosis?
A
- most plants which show chlorosis have normal genes coding for chlorophyll production
- results because of environmental factors
- *
4
Q
How does a lack of light cause chlorosis?
A
- lack of light
- in absence of light, plants will turn off their chlorophyll production to conserve resources
5
Q
How does mineral deficienies cause chlorosis?
A
- mineral deficienes
- e.g. lack of iron or magnesium
- iron is needed as a cofactor by some of the enzymes that make chlorophyll
- magnesium is found at the heart of the chlrophull molecule
- if these ions are lacking in the soil a plant simple cannot make chlorophyll
6
Q
How do viral infections cause chlorosis?
A
- when viruses infect plants, they interfere with the metabolism of cells
- a common symptom is yellowing in the infected tissues
- as they can no longer support the synthesis of chlorophyll
7
Q
How does body mass vary?
A
- determined by a combination of both genetic and environmental factors
- usually, severely underweight and obesity are a result of environmental factors
- e.g. quality and quantity of food, exercise, disease
- ocassionaly obesity can be the result of the genetic make-up of an organism
- mutations can cause a pattern of fat deposition in its body to be altered
- as well as genes that regulate the energy balance
8
Q
WHat leads to phenotypic variation?
A
- both environmental and genetic factors
