Biology Terms Flashcards

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1
Q

Organelles

A

are tiny structures that are present in a cell’s cytoplasm as discrete units normally surrounded by a membrane and responsible for a specialised function (such as photosynthesis)

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2
Q

Ultra structure

A

The ultrastructure of a cell is its fine structure as revealed at high magnification.

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3
Q

Cell Membrane

A

The cell membrane controls the movement of molecules into and out of the cell. It is described as selectively permeable.The cell membrane is made up of two types of molecule: proteins and phospholipid.

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4
Q

Passive Transport

A

Passive transport is the movement of molecules down a concentration gradient from a high concentration to a lower concentration, and does not require energy for it to take place.

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5
Q

Diffusion

A

The movement of a molecule down a concentration gradient from a high concentration to a lower concentration.

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6
Q

Osmosis -

A

Osmosis is a special case of diffusion that specifically involves water.

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7
Q

Active Transport -

A

The movement of molecules and ions against a concentration gradient, from a region of low concentration to a region of high concentration.

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8
Q

Mitosis

A

Normal cell division and provides new cells for growth and repair of damaged cells and maintains the diploid
chromosome complement

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9
Q

Complementary base pairing

A

Holds DNA strands together.
A-T
G-C

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10
Q

Base sequence codes

A

The order of bases (C-G-T-A) on a DNA/mRNA strand. The base sequence determines the amino acid sequence in a protein

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11
Q

mRNA

A

MRNA carries a complementary copy of the code from the DNA, in the nucleus, to a ribosome

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12
Q

Ribosomes

A

The site of protein synthesis - The protein is assembled from amino acids

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13
Q

Amino acids

A

coded from the sequence of base pairs. IT makes up proteins.

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14
Q

Biological catalysts

A

Speed up biochemical reactions in cells and remain unchanged in the process

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15
Q

Active site

A

Area on an enzyme’s surface that binds with a specific substance

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16
Q

Substrate

A
The reactant(s) in a reaction, and is specific to an
enzyme
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17
Q

Optimum conditions

A

Are the temperature and pH which the enzymes work best at

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18
Q

Denatured

A

When the active site permanently changes shape and affects the rate of the enzyme reaction

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19
Q

Genetic engineering

A

Transferring genetic information (DNA) from one cell into another

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20
Q

Light reactions

A

Stage one of respiration that breaks one molecule of glucose down into 2 molecules of pyruvate and releases enough energy to make 2 ATP molecules

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21
Q

Carbon fixation

A

Stage 2 with oxygen (aerobic respiration) breaks pyruvate down into carbon dioxide and water and yields 36 ATP molecules

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22
Q

Respiration

A

A series of enzyme-controlled reactions which release the chemical energy stored in glucose

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23
Q

ATP

A

Adenosine triphosphate

Molecule that is the main energy carrier molecule in cells

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24
Q

Aerobic respiration

A

Type of respiration requiring oxygen in which substrates such as glucose are completely broken down to water and carbon dioxide to release large amounts of energy

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25
Q

Anaerobic respiration

A

Respiration where oxygen isn’t present

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26
Q

Fermentation

A

Stage 2 of respiration without oxygen is called

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27
Q

Stem cells

A

Unspecialised cells which can divide in order to self- renew or differentiate (specialise) to become specialised cells

28
Q

Specialisation

A

Specialisation leads to the formation of A variety of cells, tissues and organs

29
Q

Reflex arc

A

Receptor – sensory neuron – relay neuron – motor neuron – muscle

30
Q

Central Nervous System

A

The brain and the spinal cord

31
Q

Cerebellum

A

part of the brain that controls balance and co-ordination

32
Q

Medulla

A

part of the brain that controls unconscious control of body temp, heart and breathing rate, etc.

33
Q

Cerebrum

A

part of the brain that controls conscious thought, intelligence, language

34
Q

Receptors

A

Detect stimuli / sensory information

35
Q

Hormones

A

Chemical messengers produced by endocrine glands which carry messages in the blood stream to target
tissues

36
Q

Gametes

A

Haploid sex cells

37
Q

Continuous variation

A

Where there is a range of values on a scale e.g. height

38
Q

Discrete variation

A

Discontinuous, where the values do not occur in a range and fall into distinct groups (usually descriptions
e.g. colour)

39
Q

Polygenic characteristics

A

Caused by many genes working together. They show continuous variation and very common in phenotypes.

40
Q

Phenotype

A

The visible physical characteristic you see as a result of a gene

41
Q

Genotype

A

The pair of alleles a person has which control one characteristic, e.g. AA, aa or Aa

42
Q

Homozygous

A

When a genotype has two alleles exactly the same, e.g. AA or aa

43
Q

Xylem vessel

A

Dead and contain spirals of lignin for support and transport Water and minerals up the stem

44
Q

Phloem vessel

A

Phloem transports sugar and is made of Living cells consisting of cytoplasmic strands and porous end plates between cells that allow sugar to move from
cell to cell. Companion cells provide energy for sieve tubes

45
Q

Veins

A

blood vessels that carry blood back to the heart, into the atria

46
Q

Arteries

A

blood vessels that carry blood away from the heart, from the ventricles. They carry blood under high pressure.

47
Q

Alveoli

A

Gas exchange in the lungs happens here.
The alveoli are adapted for diffusion by
1. having a large surface area (there are many of them)
2. having a good blood supply (covered by capillary
networks)
3. having thin walls (one cell thick) for more efficient diffusion

48
Q

Villi

A

Villi are

  1. thin walled
  2. have a large surface area (there are many of them)
  3. have a good blood supply to aid absorption- each villus contains a network of capillaries)
49
Q

Biotic factors

A

Living e.g competition, disease, food availability, grazing, predation

50
Q

Abiotic factors

A

Any condition affecting the environment that results from non-living sources

51
Q

Biodiversity

A

The variety of species living in a habitat

52
Q

Niche

A

The role that an organism plays within a community

53
Q

Intraspecific competitions

A

Between members of the same species competing for all the same resources they require and is therefore much
more intense that interspecific

54
Q

Interspecific competition

A

between members of different species competing for one or a few similar resources the require

55
Q

Population

A

All the organisms of one species in a habitat

56
Q

Absorption

A

Absorption

Process by which small, soluble molecules are taken up by cells

57
Q

Adenosine diphosphate

A

Molecule similar to ATP with one less phosphate group

58
Q

Community

A

All the living organisms living in a habitat

59
Q

Ecosystem

A

All the organisms (community) living in a habitat and the non-living components with which the organisms interact (the abiotic factors)

60
Q

Transpiration

A

The evaporation of water through leaves

61
Q

phagocytes

A

White blood cells called phagocytes carry out Phagocytosis to engulf and destroy pathogens

62
Q

Lymphocytes

A

White blood cells called Lymphocytes produce Antibodies which destroy pathogens

63
Q

Dominant

A

An allele which is always seen in the phenotype if it is present (in the genotype)

64
Q

Recessive

A

An allele which is only seen in the phenotype if there is no dominant allele present

65
Q

Alleles

A

Different forms of a gene which control one characteristic

66
Q

Gene

A

A section of DNA which codes for a protein (characteristic)