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Flashcards in Biology Deck (129)
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1

What is a cell's genome?

The complete set of genes in a cell

2

What is a cell's proteome?

The full range of proteins produced by the cell

3

What are alleles?

Different forms of genes

4

What are genes?

Sections of DNA that code for polypeptides

5

What is special about embryonic stem cells?

They can differentiate and give rise to any cell type

6

What happens to a cell's ability to form other cells?

It loses this ability as the cell matures

7

Describe natural selection:

Overproduction of offspring
More are produced that the environment can support
Variation exists / (random) mutations give rise to variation
Some varieties better adapted than others
Best adapted reproduce and pass on characteristics
So the new generation has these characters too
This leads to changes in the population as a whole

8

Give an example of natural selection

Bacterial resistance

9

What are the two varieties of variation?

Genetic or environmental

10

When will a species become extinct?

When they can't adapt quickly enough to changes

11

What are enzymes?

Biological catalysts

12

What is the definition of an enzyme?

Proteins that alter the rate of reaction without being affected themselves

13

Define respiration

Produces co2, h2o and ATP

14

What is the word equation for aerobic respiration?

Glucose + oxygen -> carbon dioxide + water

15

What is the word equation for anaerobic respiration in animals?

Pyruvate + reduced NAD -> lactate + oxidised NAD

16

Why is anaerobic respiration in animals important?

NAD from glycolysis must be removed - pyruvate gains two hydrogen atoms to form lactate

17

What are the male chromosomes?

XY

18

What are the female chromosomes?

XX

19

What is homeostasis?

Maintaining a constant internal environment

20

What is negative feedback?

The stimulus causes the corrective measures to be turned off to maintain optimum conditions

21

How is temperature regulated?

Hypothalamus detects a rise in temperature - this causes vasodilation, sweating and lowering of body hairs

22

How is blood glucose regulated?

Alpha cells in the islets of Langerhans detect a fall in blood glucose concentration and release glucagon
Beta cells in the islets of Langerhans detect a rise in blood glucose concentration and release insulin

23

Describe the process of denitrification

Anaerobic bacteria convert soil nitrates into nitrogen gas

24

Describe the process of nitrogen fixation

Nitrogen gas is converted to ammonia

25

Describe the process of decay

Saprobionts break down nitrogenous compounds into ammonia compounds

26

Describe the process of nitrification

Ammonia is oxidised into nitrite
Nitrite is oxidised into nitrate

27

What are mycorrhizae?

They form a mutualistic relationship with plants

28

Describe the process of phagocytosis

The phagocyte moves towards the pathogen by following chemical secretions
The phagocyte attaches to the pathogen
Lysosomes in the phagocyte engulf the pathogen
Lysozymes hydrolyse the pathogen
The hydrolysis products are absorbed the phagocyte

29

How do hormones reach their targets?

In the blood

30

How is water content regulated?

The hypothalamus of the brain detects a fall in water potential
The anti-diuretic hormone is released and travels to the kidneys, which allows more water to be absorbed