all terms Flashcards
glossary of nat 5 book
1
Q
abiotic factor
A
any condition affecting the environment that results from non-living sources
2
Q
absorption
A
process by which small soluble molecules are taken up by cells
3
Q
active site
A
area on an enzyme’s surface that binds with a specific substrate
4
Q
active transport
A
energy-demanding process in cell that moves substances against a concentration gradient
5
Q
four bases found in DNA
A
- adenine
- cytosine
- guanine
- thymine
6
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
7
Q
algal bloom
A
excess algae often associated with an increase in the nutrient level in a body of water
8
Q
allele
A
different forms of a gene
9
Q
alveolus
A
thin-walled sac where gas exchange takes place in the lungs
10
Q
amino acid
A
basic building block of protein
11
Q
amylase
A
enzyme that breaks starch down into the sugar maltose
12
Q
anther
A
male structure in a flowering plant which produces pollen
13
Q
antibody
A
large protein molecule produced in response to invasion by a foreign agent and capable of rendering it harmless
14
Q
artery
A
vessel carrying blood from the heart
15
Q
bacterial cell
A
microscopic one-celled organism with no nucleus but a definite cell wall and plasmids
16
Q
base
A
nitrogen-containing chemical such as adenine, thymine, cytosine or guanine
17
Q
biconcave
A
being curved inwards on both sides
18
Q
biodiversity
A
all the different species that live in an environment
19
Q
bioaccumulation
A
build up of pesticides accumulating in the bodies of organisms over time
20
Q
biological control
A
method of controlling pests using naturally occurring living organisms to regulate the size of the pest population
21
Q
biotic factor
A
anything that affects the environment as a result of the activities of living things
22
Q
capillary
A
smallest diameter blood vessel whose walls are only one cell thick and across which an exchange of gases, nutrients and wastes takes place
23
Q
carbon fixation
A
combination, by photosynthetic plants, of the gas carbon dioxide with hydrogen to produce glucose
24
Q
cell membrane
A
outer covering of cells that regulates what can enter or leave
25
carbohydrate
chemical containing the elements carbon, hydrogen and oxygen
26
catalyst
chemical that can speed up a reaction
27
cell wall
relatively thick layer found on the outside of plant, fungal and bacterial cells. In each case, it is chemically different but functions to give the cell shape and helps protect internal cell structures
28
cellulose
main structural chemical that makes up plant cell walls
29
central nervous system (CNS)
consists of brain and spinal cord
30
cerebellum
The part of the brain that controls balance and co-ordination
31
cerebrum
The large folded part of the brain that controls conscious responses, memory, thought and intelligence
32
chlorophyll
green pigment found in chloroplasts capable of trapping light energy
33
chloroplast
structure found in green plant cells that contains the pigment chlorophyll and where photosynthesis takes place
34
chromatid
one of the two identical strands forming a chromosome
35
chromosome
The structure made of DNA that codes for all the characteristics of an organism
36
chromosome complement
total number and types of chromosomes found in the nucleus of a cell
37
circulatory system
collective name for the blood, vessels and heart
38
collagen
important chemical found in bone and skin that gives strength
39
community
collection of animals and plants living together in a particular habitat
40
companion cell
nucleus helps regulate activity of the sieve tube cell
41
concentration gradient
The difference in concentration between two solutions, between different cells or between cells and a surrounding solution.
42
consumer
animal which feeds on other organisms to obtain energy
43
continuous variation
e.g height, body mass, circumference of wrist
44
cuticle
continuous waxy layer that covers the surfaces exposed to air
45
cytoplasm
where all the chemical reactions of the cell take place
46
decomposer
any living thing that can break down dead material to allow nutrients to be recycled in ecosystems
47
degradation
breakdown of large molecules into smaller ones
48
denaturation
irreversible change in a protein, caused by changes in pH and temperature, that renders the activity of an enzyme useless
49
diaphragm
strong sheet of muscle separating the chest cavity from the lower gut cavity and is important in breathing
50
DNA
two strands of nucleotides twisted around each other to form a shape called a double helix. contains instructions for constructing, controlling and reproducing cells by determining the synthesis of proteins
51
diffusion
the movement of substances from an area of high concentration to an area of low concentration without the use of energy
52
discrete variation
e.g ability to roll tongue, dominant hand
53
ecological barrier
means by which a species becomes divided into two or more sub-groups based on some change in the environment
54
ecosystem
all the organisms(the community) living in a particular habitat and the non-living components with which the organisms interact
55
egg
female sex cell
56
effector
structure that brings about an action as a result of an input from a nerve pathway
57
embryo
in animals development stage form foetal stage up until time of birth
58
endocrine gland
collection of cells that produce and release chemicals directly into the bloodstream
59
endocrine system
collection of glans that release chemicals directly into the bloodstream
60
enzyme
A protein which catalyses or speeds up a chemical reaction
61
epidermis
in a multicellular organism the outer layer of cells, usually one cell thick in plants
62
equator
plane of cell along which chromosomes line up during mitosis
63
ethanol
alcohol produced during anaerobic respiration by plant cells
64
evolution
the process by which living things have gradually changed over a very long period of time to become better suited to survive and reproduce in their environment
65
fatty acid
chemical that when combined with glycerol forms fat molecules
66
fat
chemical, usually solid at room temperature, used as an energy store
67
fermentation
type of anaerobic respiration found in plant and yeast cells that results in the production of ethanol, carbon dioxide and small quantities of ATP
68
fertiliser
natural or synthetically produced chemical added to soil to enhance its properties in some way
69
fertilisation
fusion of male and female gametes to form a zygote
70
foetus
young animal in its early stages of development and still within the mothers uterus
71
fungus
organism that has no chlorophyll, has a cell wall made of chitin and often feeds on dead animal or plant materials
72
gamete
sex cell that possesses half the diploid number of chromosomes
73
diploid cell
a cell that contains two sets of chromosomes
74
geographical barrier
means by which a species becomes divided into two or more sub-groups based on some major physical obstacle that prevents the sub-groups from continuing to interbreed
75
gland
organ producing a chemical that brings about a response in any body part which is sensitive to that chemical
76
glucagon
hormone produced by the pancreas that causes glycogen to be converted to glucose
77
glucose
simple 6-carbon sugar that is a product of photosynthesis and is used up in respiration
78
glycerol
a basic component of fat molecules
79
glycogen
main sugar made up of many glucose molecules and stored in the liver
80
guard cell
specialised cell that surrounds a stoma and regulates the size of the opening
81
habitat
general term for the place in an environment where an organism lives
82
haemoglobin
protein that combines loosely with oxygen in the lungs and then offloads this in respiring tissues
83
haploid cell
contains a single set of chromosomes
84
heart
muscular pump situated in the chest cavity behind the breast bone
85
heterozygote
an individual with different alleles of the same gene
86
homozygote
an individual with identical alleles of the same gene
87
hormone
chemical produced by one part of a plant or animal and transported to target areas to affect function and/or structure
88
immune system
collective name for the cells, tissues and organs which bring about a response to a pathogen and may allow the development of long-term resistance
89
indicator species
organism whose presence or absence indicates the condition of a habitat
90
impulse
of nerves, the message conducted along a nerve
91
inheritance
how characteristics in living things are passed from one generation to another
92
insulin
hormone that regulates the blood glucose levels by converting glucose to glycogen
93
inter neuron
nerve cell carrying information from sensory neurone to motor neurone
94
interspecific competition
competition between organisms of different species for the same resources
95
intraspecific competion
competition within organisms of the same species for the same resources
96
isolation
when a population is split into two or more smaller groups that are prevented from genetic exchange
97
lacteal
found in each villus, absorbs digested fats
98
lactate
formed in animal cells, end product of anaerobic respiration during activities which have a high oxygen demand e.g running
99
leaching
process by which dissolved substances, such as phosphates and nitrates in the soil are washed out by rainwater
100
lignin
substance found in the xylem of some plant cell walls that it stiffens, helping to stop infection and decay and making the xylem strong
101
limiting factor
variable that, when increased or decreased, speeds up or slows down a reaction or process
102
lymphocyte
white blood cell involved in defence and may be capable of producing antibodies
103
medulla
part of brain that controls actions such as heart rate , breathing
104
mRNA
mRNA is the substance that carries a complementary copy of a gene from the DNA in the nucleus to the ribosomes in the cytoplasm
105
micron
unit of measurement for cells where 1mm is equal to 1000 microns
106
mitochondrion
cylinder shaped structure found in varying numbers in the cytoplasm of cells that is the site of aerobic respiration producing ATP
107
mitosis
type of nuclear division that results in the formation of two new cells that share the same genetic instructions as each other and the original cell from which they arose
108
motor neuron
nerve cell carrying information towards an effector
109
mutation
change in the genetic make-up of a cell that can result in an altered phenotype , producing a new allele if a gene is affected, or a change in the number of the chromosomes
110
natural selection
mechanism by which gradual evolutionary changes take place
111
nervous system
collection of structures that allows a multicellular animal to coordinate its activities very rapidly
112
neuron
nerve cell
113
niche
role played by a particular organism in a community
114
nucleus
controls all the activities of a cell and contains the genetic material
115
oesophagus
tube connecting mouth to stomach along which food passes
116
osmosis
movement of water from an area of high water concentration to an area of low water concentration across a selectively permeable membrane
117
ovary
organ in which female sex cells are produced in animals and plants
118
oviduct
tube that carries egg from ovary towards the uterus
119
ovule
contains the female gamete in plants
120
ovum
female gamete found in humans
121
oxyhaemoglobin
formed when haemoglobin combines with oxygen
122
palisade mesophyll
cell that forms a layer between the upper and lower epidermis of a leaf, shaped tall and columnar, and where photosynthesis mainly takes place in a leaf
123
pancreas
produces important enzymes and the hormones insulin and glucagon
124
pathogen
agent such as a virus or bacterial cell which is capable of producing disease
125
phagocyte
white blood cell that can engulf and destroy pathogens
126
phloem
plant structure that moves food material made in the leaves by photosynthesis to other parts of the plant
127
plasmolysed
the condition of excessive water loss
128
pollen grain
contains male gamete in plants
129
pollen tube
narrow structure down which the male gamete travels towards the ovule
130
population
All of the members of a single species that live within a geographical area.
131
producer
green plant at start of a food chain which can photosynthesise to make its own food
132
product
end result of an enzyme catalysed reaction
133
pulmonary artery
vessel carrying blood low in oxygen from the right ventricle to the lungs
134
pulmonary vein
vessel carrying blood rich in oxygen from the lungs to the left atrium
135
receptor
cell or group of cells that responds to a specific stimulus
136
respiration
process by which energy rich molecules are progressively broken down by enzymes to form adenosine triphosphate
137
ribosome
small particle which is the site of protein synthesis in a cell
138
root hair cell
cell found in the root of a plant that has a very large surface area for absorbing water and dissolved solutes
139
speciation
formation of two or more groups of organism that fan no longer interbreed to form fertile offspring
140
spindle
network of fibres that appear during mitosis and move chromosomes within the cell
141
spongy mesophyll layer
cells that are irregularly shaped found between the upper and lower epidermis creating a large surface area and many air spaces within a leaf
142
stoma
small opening on the surface of leaves and stems that allows exchange of materials between the environment and the plant
143
synthesis
building up of large molecules from smaller ones
144
transpiration
evaporative loss of water through the surfaces of a land plant
145
turgid
condition of a plant cell that is full of water
146
vacuole
membrane-bound sac found in plant cells containing a watery solution giving support
147
valve
structure that allows movement of contents of a vessel or blood in the heart to flow in one direction only
148
vein
vessel carrying blood to the heart
149
vena cava
large vein returning blood low in oxygen to the right atrium of the heart
150
ventricle
thick-walled chamber of the heart that sends blood to the lungs or to the body
151
villus
finger-like projection lining the small intestine increasing the surface area available for absorbtion
152
xylem
group of plant cells that transport water and dissolved solutes from the roots to the leaves
153
zygote
fertilised egg at the one-cell stage that contains a full set of chromosomes
