Definitions

Question 1

Define diffusion:

Answer 1

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

Question 2

Define osmosis:

Answer 2

Osmosis as 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

Question 3

Define enzymes:

Answer 3

Enzymes as proteins that function as biological catalysts

Question 4

Define photosynthesis:

Answer 4

Photosynthesis as the process by which plants manufacture carbohydrates from raw materials using energy from light

Question 5

Define ingestion:

Answer 5

Ingestion as the taking of substances. e.g. food and drink into body through the mouth.

Question 6

Define digestion:

Answer 6

Digestion as the breakdown of large, insoluble food molecules into small, water- soluble molecules using mechanical and chemical processes

Question 7

Define mechanical digestion:

Answer 7

Mechanical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules

Question 8

Define chemical digestion:

Answer 8

Chemical digestion as the breakdown of large, insoluble molecules into small, soluble molecules

Question 9

Define absorption:

Answer 9

Absorption as movement of digested food molecules through the wall of the intestine into the blood

Question 10

Define assimilation:

Answer 10

Assimilation as the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

Question 11

Define egestion:

Answer 11

Egestion as passing out of food that has not been digested, as faeces, through the anus

Question 12

Define transpiration:

Answer 12

Transpiration as loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata

Question 13

Define translocation:

Answer 13

Translocation in terms of the movement of sucrose and amino acids in phloem:
– from regions of production (source)
– to regions of storage OR to regions where
they are used in respiration or growth (sink)

Question 14

Define aerobic respiration:

Answer 14

Aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy

Question 15

Define anaerobic respiration:

Answer 15

Anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen

Question 16

Define a hormone:

Answer 16

Hormone as a chemical substance, produced by a gland, carried by the blood, which alters the activity of one or more specific target organs

Question 17

Define homeostasis:

Answer 17

Homeostasis as the maintenance of a constant internal environment

Question 18

Define gravitropism:

Answer 18

Gravitropism as a response in which parts of a plant grow towards or away from gravity

Question 19

Define phototropism:

Answer 19

Phototropism as a response in which parts of a plant grow towards or away from the direction from which light is coming

Question 20

Define asexual reproduction:

Answer 20

Asexual reproduction as a process resulting in the production of genetically identical offspring from one parent

Question 21

Define sexual reproduction:

Answer 21

Sexual reproduction as a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other

Question 22

Define pollination:

Answer 22

Pollination as the transfer of pollen grains from the anther to the stigma

Question 23

Define inheritance:

Answer 23

Inheritance as the transmission of genetic information from generation to generation

Question 24

Define chromosome:

Answer 24

Chromosome as a thread-like structure of DNA, carrying genetic information in the form of genes

Question 25

Define gene:

Answer 25

Gene as a length of DNA that codes for a protein

Question 26

Define allele:

Answer 26

Allele as a version of a gene

Question 27

Define haploid nucleus:

Answer 27

Haploid nucleus as a nucleus containing a single set of unpaired chromosomes, e.g. in gametes

Question 28

Define diploid nucleus:

Answer 28

Diploid nucleus as a nucleus containing two sets of chromosomes, e.g. in body cells

Question 29

Define mitosis:

Answer 29

Mitosis as nuclear division giving rise to genetically identical cells

Question 30

Define meiosis:

Answer 30

Meiosis as reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

Question 31

Define genotype:

Answer 31

Genotype as the genetic make-up of an organism in terms of the alleles present

Question 32

Define phenotype:

Answer 32

Phenotype as the observable features of an organism

Question 33

Define homozygous:

Answer 33

homozygous as having two identical alleles of a particular gene

Question 34

Define heterozygous:

Answer 34

Heterozygous as having two different alleles of a particular gene

Question 35

Define dominant:

Answer 35

Dominant as an allele that is expressed if it is present

Question 36

Define recessive:

Answer 36

Recessive as an allele that is only expressed when there is no dominant allele of the gene present

Question 37

Define variation:

Answer 37

Variation as differences between individuals of the same species

Question 38

Define mutation:

Answer 38

Mutation as a change in a gene or chromosome

Question 39

Define the process of adaptation:

Answer 39

The process of adaptation as the process, resulting from natural selection, by which populations become more suited to their environment over many generations

Question 40

Define food chain:

Answer 40

Food chain as showing the transfer of energy from one organism to the next, beginning with a producer

Question 41

Define food web:

Answer 41

Food web as a network of interconnected food chains

Question 42

Define producer:

Answer 42

Producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis

Question 43

Define consumer:

Answer 43

Consumer as an organism that gets its energy by feeding on other organisms

Question 44

Define herbivore:

Answer 44

Herbivore as an animal that gets its energy by eating plants

Question 45

Define carnivore:

Answer 45

Carnivore as an animal that gets its energy by eating other animals

Question 46

Define decomposer:

Answer 46

Decomposer as an organism that gets its energy from dead or waste organic matter

Question 47

Define ecosystem:

Answer 47

Ecosystem as a unit containing all of the organisms and their environment, interacting together, in a given area, e.g. a lake

Question 48

Define trophic level:

Answer 48

Trophic level as the position of an organism in a food chain or food web