Definitions Flashcards

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1
Q

Anticodon

A

A sequence of 3 adjacent nucleotides on a molecule of tRNA that is complementary to a particular codon on a mRNA molecule

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2
Q

Cardiac Muscle

A

Type of muscle found only in the heart. Fewer striations than skeletal muscle and can contract continuously throughout life without stimulation by nerve impulses.

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3
Q

Clone

A

A group of genetically identical organisms formed form a single parent as a result of asexual reproduction or by artificial means

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4
Q

Dendrite

A

Extending from the cell body of a neurone -> conducts impulses towards the cell body

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5
Q

Depolarisation

A

Temporary reversal of charges on the csm of a neurone that takes place when a nerve impulse is transmitted

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6
Q

Diabetes

A

A metabolic disorder in which the body is unable to regulate the level of blood glucose

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7
Q

DNA helicase

A

Enzyme that acts on a specific region of the DNA molecule to break the hydrogen bonds between bases causing 2 strands to separate and expose the nucleotide bases in that region

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8
Q

Ectotherm

A

An organism that uses the environment to regulate its body temperature

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9
Q

Gene marker

A

A section of DNA that’s used to indicate the location of a gene or other section of DNA

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10
Q

Gene therapy

A

A mechanism by which genetic diseases may be cured by masking the effect of the defective gene by inserting a functional gene

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11
Q

Generator potential

A

Depolarisation of the membrane of a receptor cell as a result of a stimulus

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12
Q

GMO

A

Organism that has had its DNA altered as a result of recombinant DNA technology

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13
Q

Glucagon

A

A hormone produced by alpha cells of the islets of Langerhan the pancreas that increases blood glucose levels by initiating the breakdown of glycogen to glucose

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14
Q

Gluconeogensis

A

The conversion of non-carbohydrate molecules to glucose

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15
Q

Glycogenesis

A

The conversion of glucose to glycogen

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16
Q

Hypothalamus

A

A region of the brain adjoining the pituitary gland that acts as the control centre for the autonomic nervous system and regulates body temperature and fluid balance

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17
Q

Insulin

A

A hormone produced by beta cells of the islets of Langerhans in the pancreas, which decreases blood glucose levels by increasing the rate of conversion of glucose to glycogen

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18
Q

Ligament

A

A tough fibrous connective tissue, rich in collagen that joins bone to bone

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19
Q

Motor neurone

A

Neurone that transmits action potential from the CNS to an effector

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20
Q

Mutagen

A

Any agent that induces a mutation

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21
Q

Mutation

A

A change in teh sequence of bases in DNA

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22
Q

Myelin

A

A fatty substance that surrounds axons and dendrites

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23
Q

Negative feedback

A

A serious of changes that result in a substance being restored to its normal level

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24
Q

Neurotransmitter

A

One of a number of chemicals that are involved in communication between adjacent neurones or between nerve cells and muscles.

25
Q

node of Ranvier

A

Gap in myelin sheath

26
Q

Normal distribution

A

Bell shaped curve

27
Q

Oestrous

A

The period in the oestrous cycle immediately after ovulation when the female is most fertile

28
Q

Oncogenes

A

Mutated proto-oncogenes that result in increased cell division leading to the growth of a tumour

29
Q

Pentose sugar

A

In ribose and deoxyribose

30
Q

Plasmid

A

Small circular piece of DNA found in bacterial cells

31
Q

Polygenes

A

Group of genes that are responsible for controlling a characteristic

32
Q

PCR

A

Process of making many copies of a specific sequence of DNA or part of a gene

33
Q

Positive feedback

A

Process which results in a substance that departs from its normal level becoming further from its normal

34
Q

Receptor

A

A cell adapted to detect changes in the environment

35
Q

Recognition site

A

A nucleotide sequence that is recognised by a restriction endonuclease when it attaches

36
Q

Recombinant DNA Technology

A

Processes by which genes are manipulated, altered or transferred from organism to organism

37
Q

Reflex arc

A

The nerve pathway in the body taken by an action potential that leads to a rapid, involuntary response to a stimulus

38
Q

Refractory period

A

Membrane of the axon of a neurone can’t be depolarised so no new action potential can be initiated -> prevents continuous nerve impulses

39
Q

Repolarisation

A

Return to resting potential in the axon of a neurone after an action potential

40
Q

Resting potential

A

The difference in electrical charge maintained across the membrane of the axon of a neurone when not stimulated

41
Q

RNA polymerase

A

Enzyme that joins together nucleotides to form mRNA during transcription

42
Q

Restriction endonuclease

A

A group of enzymes that cut DNA molecules at a specific sequence of bases called a recognition site

43
Q

Saltatory conduction

A

Propagation of a nerve impulse along a myelinated dendron or axon in which the action potential moves by saltatory conduction through adjacent nodes of Ranvier

44
Q

Sacromere

A

A section of myofibril between two adjacent Z lines that form the basic structural unit of skeletal muscle

45
Q

Schwann cell

A

Cell around a neurone whose csm wraps around the dendron or axon to form a myelin sheath

46
Q

Sensory neurone

A

transmits an a.p. from a sensory receptor to CNS

47
Q

Skeletal muscle

A

Makes up the bulk of the body and works under conscious control -> voluntary muscle

48
Q

SAN

A

An area of the heart muscle in the right atrium that controls and coordinates the contraction of the heart

49
Q

Smooth muscle

A

Involuntary + unstriated found in the alimentary canal and the walls of blood vessels. Its contraction is not under conscious control

50
Q

Stem cells

A

Undifferentiated dividing cells

51
Q

Synapse

A

A junction between 2 neurones where they do not touch across which a NT can pass

52
Q

Tendon

A

Tough, flexible but inelastic connective tissue that joins muscle to bone

53
Q

Threshold value

A

The minimum intensity a stimulus must reach in order to trigger an action potential in a neurone

54
Q

Transducer cells

A

Cells that convert a non-electrical signal into an electrical nervous signal

55
Q

Tumour suppressor gene

A

A gene that maintains normal rates of cell division preventing the development of tumours

56
Q

Vasoconstriction

A

Narrowing of the internal diameter of blood vessles

57
Q

Vasodilation

A

Widening of the internal diameter of blood vessels

58
Q

Vector

A

A carrier e.g. a plasmid which carries DNA into a cell