Biology Flashcards

1
Q

Concentration gradient

A

Difference in concentration between 2 regions

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2
Q

Diffusion

A

net movement of particles from a region of higher concentration to a region of lower concentration
down a concentration gradient

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3
Q

Osmosis

A

net movement of water molecules from a solution of higher water potential to a solution of lower water potential through a partially permeable membrane

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4
Q

Active transport

A

process in which energy is used to move the particles of a substance across a membrane against its concentration gradient, that is from a region of lower concentration to a region of higher concentration

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5
Q

Carbohydrates

A

organic molecules made up of the elements carbon, hydrogen and oxygen. The hydrogen and oxygen atoms are present in the ratio 2:1

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6
Q

Condensation reaction

A

Chemical reaction in which 2 simple molecules are joined together to form a larger molecule with the removal of 1 molecule of water

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7
Q

Hydrolysis

A

reaction in which a water molecule is needed to break up a complex molecule into smaller molecules

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8
Q

fats

A

organic molecules made up of the elements carbon, hydrogen and oxygen but with much less oxygen in proportion to hydrogen compared to carbohydrates

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9
Q

Proteins

A

organic molecules made up of the elements carbon, hydrogen, oxygen and nitrogen. sulfur may also be present

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10
Q

Catalyst

A

substance which can alter or speed up a chemical reaction, without itself being chemically changed at the end of the reaction

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11
Q

enzymes

A

proteins that function as biological catalysts

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12
Q

denaturation

A

change in the 3D structure of an enzyme or any other soluble protein, caused by heat or chemicals such as acids or alkalis

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13
Q

nutrition

A

process by which organisms obtain food and energy for growth, repair and maintenance of the body

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14
Q

peristalsis

A

rhythmic wave-like muscular contractions in the wall of the alimentary canal

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15
Q

digestion

A

process whereby large food molecules are broken down into smaller, soluble molecules that can be absorbed into the body cells

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16
Q

absorption

A

process whereby digested food substances are absorbed into the body cells

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17
Q

assimilation

A

process whereby some of the absorbed food substances are converted into new protoplasm or used to provide energy

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18
Q

photosynthesis

A

process in which light energy absorbed by chlorophyll is transformed into chemical energy. the chemical energy is used to synthesise carbohydrates from water and carbon dioxide. water and carbon dioxide are raw materials for photosynthesis. oxygen is released during the process

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19
Q

phagocytosis

A

process of engulfing or ingesting foreign particles such as bacteria by the white blood cells

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20
Q

transpiration

A

loss of water vapour from a plant, mainly through the stomata of the leaves

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21
Q

respiration

A

breakdown (oxidation) of food substances with the release of energy in living cells

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22
Q

aerobic respiration

A

breakdown of food substances in the presence of oxygen with the release of a large amount of energy. carbon dioxide and water are released as waste products.

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23
Q

anaerobic respiration

A

breakdown of food substances in the absence of oxygen. releases less energy than aerobic respiration

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24
Q

gas exchange

A

exchange of gases between an organism and the environment

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25
excretion
process by which metabolic waste products and toxic substances are removed from the body of an organism
26
osmoregulation
control of water and solute concentrations in the blood to maintain a constant water potential in the body
27
homeostasis
Homeostasis is the maintenance of a constant internal environment through self-regulatory corrective mechanisms
28
reflex action
immediate response to a specific stimulus without conscious control
29
reflex arc
shortest pathway by which nerve impulses travel from the receptor to the effector in a reflex action
30
focusing/accommodation
adjustment of the lens of the eye so that clear images of objects at different distances are formed on the retina
31
hormone
chemical substance produced in minute quantities by an endocrine gland. it is transported in the bloodstream to target organs where it exerts its effects. after hormones have performed their functions, they are eventually destroyed by the liver
32
growth
permanent increase in size accompanied by cell division and differentiation to form tissues and organs. characteristic of all living things
33
mitosis
a form of nuclear division that produces daughter nuclei containing the same number of chromosomes as the parent nucleus. the daughter nuclei are genetically identical
34
meiosis
a form of nuclear division that produces daughter nuclei containing half the number of chromosomes as the parent nucleus
35
asexual reproduction
process resulting in the production of genetically identical offspring from one parent, without the fusion of gametes
36
sexual reproduction
process involving the fusion of 2 gametes to form a zygote. it produces genetically dissimilar offspring
37
pollination
transfer of pollen grains from the anther to the stigma
38
self-pollination
transfer of pollen grains from the anther to the stigma of the same flower or of a different flower on the same plant
39
cross-pollination
transfer of pollen grains from one plant to the stigma of a flower in another plant of the same species
40
puberty
stage of human growth and development in which a person becomes physically mature
41
monohybrid inheritance
inheritance involving only one pair of contrasting traits
42
chromosome
rod-like structure visible in the nucleus during cell division. it is made up of the molecule deoxyribonucleic acid (DNA)
43
gene
a unit of inheritance, born on a particular locus (position) of a chromosome. It is a small segment of DNA in a chromosome that controls a particular characteristic or protein in an organism
44
alleles
different forms of the same gene. they occupy the same relative positions on a pair of homologous chromosomes
45
phenotype
refers to the expressed trait in an organism.
46
genotype
genetic make-up (pairs of alleles) of an organism, that is, the combination of genes in an organism
47
co-dominance
results when the 2 alleles controlling a trait both express themselves in the organism
48
multiple alleles
a gene that exists in more than 2 alleles
49
variations
differences in traits between individuals of the same species
50
mutation
sudden random change in the structure of a gene or in the chromosome number
51
Transgenic organism
A transgenic organism is an organism with genetic characteristics that have been altered/modified by the artificial insertion of a modified gene or a gene from another organism using techniques of genetic engineering.
52
genetic engineering
technique used to transfer genes from one organism to another. Individual genes may be cut off from the cells of one organism and inserted into the cells of another organism of the same or different species. the transferred gene can express itself in the recipient organism
53
habitat
place where an organism lives
54
ecology
study of interactions among organisms, and between organisms and the physical and chemical factors making up their external environment
55
population
a group of organisms of the same species that live together in a habitat
56
community
all the populations living and interacting with one another in a habitat
57
biosphere
A combination of different ecosystems
58
ecosystem
a community of organisms interacting with one another and with its abiotic environment
59
abiotic environment
climate and physical features of the surroundings. physical features include light intensity, temperature, water availability, oxygen content, salinity and pH of soil and water.
60
food chain
a series of organisms through which energy is transferred in the form of food
61
food web
consists of interlinked food chains
62
producers
organisms that can make their own food by photosynthesis
63
biomass
total dry mass of living matter in each trophic level at a particular time.
64
parasitism
The association between two organisms such that the parasite lives in or on the body of the host and derives nutrients and shelter from the host. The parasite normally does some harm to the host.
65
carbon sink
an area that stores carbon compounds for an indefinite period. it stores more carbon than it releases
66
deforestation
clearing of trees
67
pollution
addition of substances to the environment that damage it, making it undesirable or unfit for life. Substances that cause pollution are called pollutants
68
eutrophication
process whereby water receives excess nutrients like phosphates and nitrates, which causes excessive growth of algae and water plants
69
bioaccumulation
when chemicals are not excreted but are accumulated in the bodies of organisms
70
bioamplification
when chemicals accumulated in bodies of organisms are passed along the food chain, increasing in concentration in the bodies of organisms along the trophic levels
71
biodiversity
range of species that are present in a particular ecosystem
72
conservation
protection and preservation of natural resources in the environment
73
Differentiation
Process by which a cell becomes specialised for a specific function
74
Tissue
A group of cells with similar structures which work together to perform a specific function