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Biology O-Level > Biology Definitions > Flashcards

Biology Definitions Flashcards

Questions that start with "define" or "what is".

1
Q

What is destarching?

A

Leaving a plant in the dark for 48 hours to ensure that any starch produced is during the experiment and was not stored previously.

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2
Q

What is the chemical composition of proteins?

A

Carbon, Hydrogen, Oxygen, Nitrogen

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3
Q

What is the optimum temperature?

A

The temperature at which the enzymes work best.

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4
Q

What is the balanced chemical equation of photosynthesis?

A

6CO2 + 6H2O => C6H12O6 + 6O2

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5
Q

What are enzymes?

A

Proteins that are involved in all metabolic reactions, where they function as biological catalysts.

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6
Q

What is turgor pressure?

A

The pressure of water inside the cells pressing outwards on the cell wall.

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7
Q

What is sensitivity in organisms?

A

The ability to detect and respond to changes in the internal or external environments.

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8
Q

What is osmosis?

A

The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane.

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9
Q

What defines the plant kingdom?

A

Multicellular organisms which make their own food by carrying out photosynthesis and their cells have cellulose cell walls and chlorophyll.

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10
Q

What is movement in biological terms?

A

An action by an organism or part of an organism causing a change of position or place.

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11
Q

What is a species?

A

A group of organisms that can reproduce to produce fertile offspring.

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12
Q

What is the binomial system of naming species?

A

An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species in Latin.

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13
Q

What is respiration?

A

The chemical reaction in cells that break down nutrient molecules and release energy for molecules.

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14
Q

What is reproduction?

A

The processes that make more of the same kind of organism.

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15
Q

What are flowering plants?

A

Plants that reproduce by flowers and seeds and they don’t need water for fertilization (it is needed for seed germination).

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16
Q

What is tissue?

A

A group of cells with similar structures, working together to perform a shared function.

(e.g. Xylem Vessels, Muscles)

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17
Q

What is active transport?

A

The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration, against a concentration gradient, using energy from respiration.

(done by protein carriers)

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18
Q

What defines the prokaryote kingdom?

A

Mostly unicellular organisms with no nucleus, mitochondria, chloroplasts, or ER in their cells. Circular DNA, plasmids, and sometimes flagellum can be found.

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19
Q

What defines the animal kingdom?

A

Multicellular organisms which eat other living organisms.

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20
Q

What is nutrition?

A

The taking in of materials for energy, growth, and development.

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21
Q

What are invertebrates?

A

Animals without a backbone.

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22
Q

What is a cell?

A

Structural and functional unit of body.

(e.g. Palisade Mesophyll Cell, Red Blood Cell)

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23
Q

What defines the fungi kingdom?

A

Unicellular or multicellular organisms which eat other living organisms as well as dead organisms, and they spread by spores in moist dark environments, and their cells have cell walls.

(made of strands called hyphae, they feed by secreting enzymes to digest food by Saprophytic Digestion)

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24
Q

What is a catalyst?

A

A substance that increases the rate of a chemical reaction and is not changed by the reaction.

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25
Q

What is photosynthesis?

A

The process by which plants synthesize carbohydrates from raw materials using energy from light.

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26
Q

What is an organ?

A

A group of tissues in a structure, working together to perform a specific function.

(e.g. Pancreas, Stomach)

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27
Q

What are ferns?

A

Plants that reproduce by spores, and they don’t have pollen, fruits, flowers, and seeds, and they need water for fertilization.

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28
Q

What is optimum pH?

A

The pH at which the enzymes work best.

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29
Q

What is diffusion?

A

The net movement of particles from a region of their higher concentration to a region of their lower concentration, down the concentration gradient, as a result of their random movement.

(using energy from the kinetic energy of random movement of molecules and ions)

30
Q

What are vertebrates?

A

Animals with a backbone.

31
Q

What are viruses?

A

Non-living organisms (because they do not do any characteristics of living organisms except for reproduction), with defining features like a protein coat and genetic material (DNA or RNA), but with no cell membrane, cytoplasm, and ribosomes.

32
Q

What is chlorophyll?

A

Green pigment found in chloroplasts.

33
Q

What is the chemical composition of fats?

A

Carbon, Hydrogen, Oxygen.

34
Q

What is denaturing?

A

Changing the active site of the enzyme, so the active site is not complementary to the substrate anymore, so the substrate does not fit.

35
Q

What defines the protoctist kingdom?

A

Organisms with a nucleus in their cells.

36
Q

What is the chemical composition of carbohydrates?

A

Carbon, Hydrogen, Oxygen.

37
Q

What is growth?

A

The permanent increase in size and dry mass by an increase in cell size/cell number.

38
Q

What is the word equation of photosynthesis?

A

Carbon Dioxide + Water => Glucose + Oxygen in the presence of light and chlorophyll.

39
Q

What are arthropods?

A

Invertebrates with segmented bodies, jointed legs, and an exoskeleton.

40
Q

What is an organ system?

A

A group of organs with related functions, working together to perform body functions.

(e.g. Circulatory System, Respiratory System)

41
Q

What is the structure of a DNA molecule?

A

Two strands coiled together to form a Double Helix. Each strand contains chemicals called bases. Bonds between the bases hold the strands together. The bases always pair up in the same way: A with T, and C with G.

42
Q

What is excretion?

A

The removal of the waste products of metabolism and substances in excess of requirements.

43
Q

What is a balanced diet?

A

The daily intake of food containing all nutrients in correct proportions according to age, gender, and activity.

44
Q

What is ingestion?

A

The taking in of substances into the body, through the mouth.

45
Q

What is digestion?

A

The breakdown of food.

46
Q

What is absorption?

A

The movement of nutrients from the intestines into the blood.

47
Q

What is assimilation?

A

The uptake and use of nutrients by cells, becoming a part of the cells.

48
Q

What is egestion?

A

The removal of undigested food from the body as faeces.

49
Q

What is physical digestion?

A

The breakdown of food into smaller pieces without chemical change to the food molecules.

50
Q

What is enamel?

A

Non-living layer made of calcium which can be dissolved by acids, found in the Crown only.

51
Q

What is dentine?

A

Living layer made of calcium, found in both Crown and Root.

52
Q

What is pulp in a tooth?

A

Contains nerves for sensation and blood vessels for food and oxygen, present in the center of the tooth.

53
Q

What is cement in a tooth?

A

Collagen fibers which attach the tooth to the jawbone.

54
Q

What is chemical digestion?

A

The breakdown of large insoluble molecules into small soluble molecules that can be absorbed.

55
Q

Where is amylase secreted and what is its pH?

A

Secreted in mouth by salivary glands (neutral). Secreted in small intestines by pancreas (alkaline).

56
Q

Where is maltase secreted and what is its pH?

A

Secreted in the small intestines by the epithelium lining of the intestine (alkaline).

57
Q

Where is protease secreted and what is its pH?

A

Pepsin: Secreted in the stomach (acidic). Trypsin: Secreted in the small intestines by the pancreas (alkaline). Protease: Secreted in the small intestines (alkaline).

58
Q

Where is lipase secreted and what is its pH?

A

Secreted in the small intestines by the pancreas and by the small intestine (alkaline).

59
Q

What is peristalsis?

A

Rhythmic contractions and relaxations of the muscles of the organ.

60
Q

What is bile juice?

A

Alkaline mixture, produced in the liver, stored at the gall bladder.

61
Q

What is the structure of the villi?

A

One cell thick epithelium lining to increase diffusion/absorption rate. Contains many mitochondria to provide energy. Has many microvilli to increase surface area to increase rate of diffusion and active transport. Contains many protein carriers to increase rate of active transport/absorption.

62
Q

What is the structure of xylem vessels?

A

Thick walls to withstand high pressure. Walls made of lignin to prevent collapsing and for support. No end walls to reduce resistance to water flow. Pits to allow for the lateral movement of water.

63
Q

What is the pathway of water in plants?

A

Root Hair Cell → Root Cortex Cell → Xylem → Mesophyll Cells.

64
Q

What is transpiration?

A

Loss of water vapor from leaves by the evaporation of water from the surfaces of the mesophyll cells into the air spaces, then the diffusion of water vapor from the stomata.

65
Q

What is transpiration pull?

A

Describes transpiration first, which decreases the pressure at the top of the plant, which draws up an unbroken column of water molecules, held together by cohesion forces, which are the forces of attraction between water molecules, moving the water upwards.

66
Q

What are cohesion forces?

A

Force of attraction between water molecules.

67
Q

What is wilting?

A

Water loss is more than water uptake (Lack of water), so water leaves the cells by osmosis, so water exerts less turgor pressure on the cell walls, plant cells become flaccid/plasmolyzed. Cells cannot provide support.

68
Q

What is translocation?

A

The movement of sucrose and amino acids in the phloem from sources to sinks.

69
Q

What are sources in plants?

A

Parts of a plant that release sucrose or amino acids.

70
Q

What are sinks in plants?

A

Parts of a plant that use or store sucrose or amino acids.

Biology O-Level (2 decks)

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