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Flashcards in B2 Deck (119)
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1
Q

Differentiation

A

When a cell develops into a type that is specialised for a specific function.

2
Q

Bacteria

A
  • single celled micro-organism (1-5 nm)

- contains no nucleus but genetic material

3
Q

Specialised cell

A

A cell that has a structure well suited to its function.

4
Q

Cell

A

The building block of living things

5
Q

Multicellular

A

Being built up of many cells, all working together as an organism.

6
Q

Tissue

A

Group of similar cells working together to perform a common function e.g. muscle or xylem.

7
Q

Organ

A

Collection of different tissues working together to perform a function within an organism e.g. stomach, or leaf.

8
Q

Organ system

A

Collection of different organs working together to perform a major function within an organism e.g. digestive system, or flower.

9
Q

Cytoplasm

A

Jelly-like contents of a cell where many chemical reactions take place.

10
Q

Cell membrane

A

A thin layer around a cell that controls the movement of substances into and out of the cell.

11
Q

Palisade mesophyll

A

Layer of tall column shaped cells in the leaf containing chloroplasts, where the majority of photosynthesis occurs.

12
Q

Chlorophyll

A

Green pigment found in chloroplasts, that traps light energy for photosynthesis.

13
Q

Photosynthesis

A

Chemical reaction that enable plants to build carbohydrates from carbon dioxide and water, using energy from sunlight.

14
Q

Rate of photosynthesis

A

How quickly a plant is photosynthesising. This is affected by factors including levels of CO2, light, and temperature.

15
Q

Limiting factor

A

E.g. carbon dioxide level, light intensity or temperature, which will affect the rate of photosynthesis if it is in short supply.

16
Q

Distribution

A

Detail of where species are found over the total area of where they occur. E.g. woodlice have a high distribution under a log.

17
Q

Epidermal tissue

A

Tissue one cell thick on the surface of plant roots, stems and leaves, that protects the organs.

18
Q

Population

A

The number of organisms of the same species in a selected area.

19
Q

Community

A

All the populations of organisms that live together and interact in the same area.

20
Q

Relationship

A

Interaction between different species living together in the same area.

21
Q

Sampling

A

Counting a small number of a large total population in order to study its distribution.

22
Q

Quadrat

A

A quadrat is a square grid used in ecology for sampling purposes.

23
Q

Transect

A

A line or path through part of the environment showing a range of different habitats.

24
Q

Protein

A

Large molecules made up of many amino acids. Many roles within organisms, e.g. muscle, hormones and enzymes.

25
Q

Amino acids

A

The building blocks of proteins. When proteins are digested, amino acids are absorbed into the blood.

26
Q

Enzyme

A

Biological catalyst made of protein. They catalyse chemical reactions in living organisms.

27
Q

Substrate

A

Substance acted upon by an enzyme in a chemical reaction.

28
Q

Denatured

A

When the shape of an enzyme has altered and it can no longer carry out its function. Often caused by temperature or pH.

29
Q

Chemical digestion

A

The break down of food within the body due to the action of enzymes on large food molecules.

30
Q

Amylase

A

An enzyme that catalyses the breakdown of starch into sugar molecules.

31
Q

Protease

A

An enzyme that catalyses the breakdown of proteins to amino acids.

32
Q

Lipase

A

Enzyme that catalyses the breakdown of fats (lipids) into fatty acids and glycerol.

33
Q

Biological detergent

A

Detergent that contains enzymes.

34
Q

Carbohydrase

A

E.g. Amylase - Enzymes that catalyse the breakdown of large carbohydrate molecules e.g. starch into smaller sugar molecules.

35
Q

Chloroplast

A

Small disc in the cytoplasm of plants containing chlorophyll for photosynthesis.

36
Q

Fermenters

A

Large container used for growing large numbers of microorganisms.

37
Q

Permanent vacuole

A

Fluid-filled area in plant cells, containing sap.

38
Q

Nucleus

A

Controls the activities of the cell. It contains chromosomes made of DNA.

39
Q

Mitochondria

A

The site of aerobic respiration in plant and animal cells.

40
Q

Fungi

A

Organisms with a cell wall made of chitin, rather than the cellulose found in plant cell walls.

41
Q

Concentration gradient

A

Difference in concentration of a substance from one area to another.

42
Q

Xylem

A

Plant tissue, made up of dead cells, that has the function of transporting water and dissolved substances through the plant.

43
Q

Phloem

A

Plant tissue, made up of living cells, that has the function of transporting food substances through the plant.

44
Q

Cell wall

A

Rigid cellulose layer outside the cell membrane of a plant or bacterial cell.

45
Q

Isomerase

A

Type of enzyme that rearranges the atoms of a molecule. E.g. when converting glucose into fructose.

46
Q

Diffusion

A

the spreading out of particles from an area of high concentration to an area of low concentration

47
Q

Stomata

A

Pores (holes) on the surface of a leaf that allows water, carbon dioxide, and oxygen to move in and out of the leaf.

48
Q

Ribosomes

A

where proteins are made

49
Q

What is yeast?

A
  • a single celled micro-organism
50
Q

How are palisade cells specialised?

A
  • packed with chloroplasts for photosynthesis

- large surface area

51
Q

How are guard cells specialised?

A
  • adapted to open and close the stomata
52
Q

How are red blood cells specialised?

A
  • bi-concave shape gives a large surface area for oxygen absorption
  • lots haemoglobin
  • no nulceus
53
Q

How are egg cells specialised?

A
  • food reserves to feed the embryo
  • haploid nucleus
  • special cell membrane which only allows one sperm to fertilise it.
54
Q

How are sperm cells specialised?

A
  • long tail & streamlined head to swim

- enzymes to digest the eggs cell membrane

55
Q

Mitosis

A

Cell division that occurs in body cells, resulting in 2 genetically identical cells.

56
Q

Chromosome

A

Structure in a cell nucleus that is made up of a DNA molecule that has been condensed and coiled.

57
Q

Diploid

A

Describes a cell that has a nucleus with two sets of chromosomes e.g. body cells.

58
Q

Respiration

A

Chemical reaction within cells by which living things release energy from carbohydrates, producing CO2 and water.

59
Q

Asexual reproduction

A

Reproduction without gametes, using mitosis. E.g. in bacteria.

60
Q

Allele

A

A version of a gene.

61
Q

Meiosis

A

Cell division that occurs to form sex cells (gametes), resulting in 4 unique cells.

62
Q

Gametes

A

Sex cells. They contain half the normal number of chromosomes for the specific organism.

63
Q

Haploid

A

Describes a cell that has a nucleus with only one set of chromosomes e.g. sex cells.

64
Q

Zygote

A

Diploid cell resulting from the fusion of an egg and a sperm.

65
Q

Fertilisation

A

The joining of the male and female gametes to make a new individual.

66
Q

Dominant

A

Visible characteristic found in an organism even when only one allele of the gene is present.

67
Q

Recessive

A

A visible characteristic that is only present if two copies of the same allele are inherited.

68
Q

Inheritance factor

A

A term used by Mendel. We now call this a gene.

69
Q

Gregor Mendel

A

Discovered that inheritance was due to inheritance factors and not caused by a blending mechanism.

70
Q

DNA

A

An acid that carries the genetic information in cells

71
Q

Gene

A

Section of DNA that codes for a characteristic or protein.

72
Q

Punnett square

A

A grid used to represent the genetic cross of gametes during sexual reproduction.

73
Q

Sex chromosomes

A

Chromosomes that decide on the sex of an individual.

74
Q

Cystic Fibrosis

A

A genetically inherited disorder that affects cell membranes. Excess mucus in the airwaves is a common symptom.

75
Q

Stem cell

A

An undifferentiated cell that can divide by mitosis. It is able to differentiate into some or sometimes all of the bodies cell types.

76
Q

DNA fingerprinting

A

Technique that analyses parts of the DNA of an individual and compares it with DNA from other individuals. Used to solve crimes, and check if people are related.

77
Q

Evolution

A

Gradual change in an organism over time.

78
Q

Fossil

A

Preserved remains of ancient living things.

79
Q

Endangered

A

Describes a species that has low numbers and is in danger of becoming extinct.

80
Q

Extinction

A

End of a species, when all of its members have dies out.

81
Q

Speciation

A

Separate evolution of two populations of the same species, to form two separate species.

82
Q

Isolation

A

Separation of two populations of a species so that they cannot interbreed. E.g. by a geographical barrier such as a mountain range.

83
Q

Mutation

A

Change in the structure of a gene. A mutation may cause a gene to code for a different characteristic.

84
Q

Natural selection

A

The survival of better-adapted organisms.

85
Q

Glycogen

A

Large carbohydrate molecule; similar to starch but found only in animal cells, and some bacterial and fungal cells.

86
Q

Anaerobic

A

When oxygen is not present or being used.

87
Q

Lactic acid

A

Chemical made from the incomplete breakdown of glucose during anaerobic respiration.

88
Q

Fatigue

A

Build up of lactic acid in muscles that stops them contracting properly.

89
Q

Oxygen debt

A

Lack of oxygen in muscle cells. Oxygen is needed to oxidise lactic acid in the muscle.

90
Q

How are fossils formed by mineral replacement?

A
  • hard body parts (e.g. teeth & bones) are buried
  • they are eventually replaced by minerals as the decay
  • the pattern stays distinctly in the rock as a fossil
91
Q

How are fossils formed by traces?

A
  • things such as foot prints and droppings may be fossilised

- soft substances like clay may harden and leave impressions

92
Q

How are fossils formed by no decay?

A
  • a condition for no decay is present e.g. no ozygen

- e.g. ice, amber or peat bogs

93
Q

Why were early organisms unknown?

A
  • they were soft bodied (hard to fossilise)

- fossils may have been destroyed by geological activity

94
Q

why might a species go extinct?

A
  • environmental changes
  • new predator
  • new disease
  • catastrophic event
  • a new species develops
  • different species takes all the food resources
95
Q

how does speciation take place?

A
  • population becomes geographically isolated from the original population
  • different environmental conditions in the new population
  • mutations may occur creating variation in the new population
  • natural selection occurs whereby the best adapted individuals survive and reproduce passing on alleles
  • the new population eventually changes to the point where it cannot interbreed with the old population
96
Q

genotype

A

what alleles you have

97
Q

phenotype

A

characteristic which is shown

98
Q

polydactyly

A

dominant genetic disorder where babies are born with extra fingers/toes

99
Q

Advantages of embryo sceening

A
  • stops people suffering

- saves money for treating disorders

100
Q

Disadvantages of embryo sceening

A
  • expensive
  • implies that people with disorders are undesirable
  • embryos which are not wanted are destroyed
  • may go to far e.g. picking desirable characteristics
101
Q

homozygous

A

two copies of the same allele (DD or dd)

102
Q

heterozygous

A

two different alleles (Dd)

103
Q

Where is amylase produced?

A
  • salivary glands
  • pancreas
  • small intestine
104
Q

Where is Protease produced?

A
  • stomach
  • pancreas
  • small intestine
105
Q

Where is Lipase produced?

A
  • panmcreas

- small intestine

106
Q

What is bile and why is it needed?

A
  • produced in the liver and stored in the gall bladder
  • Bile is alkaline and neutralises the acid from the stomach so that enzymes int the small intestine can work properly
  • emulsifies fats giving a bigger surface area for the lipase to work
107
Q

What factors effect ditrubution?

A
  • temperature
  • availability of water
  • availability of oxygen and CO2
  • availability of nutrients
  • availability light
108
Q

How does increased blood supply help during exercise?

A
  • transports more glucose and oxygen
  • more respiration occurs
  • more energy released for muscle contractions
109
Q

What does glandular tissue do in the stomach?

A
  • produces enzymes which break down proteins

- produces HCL which kills pathogens

110
Q

Why does using the stem cells of someone who has a genetic disorder not work?

A

because the cell contains the alleles for the genetic disorder

111
Q

How can you improve sampling with a quadrat?

A

randomly chose the placement of the quadrat (more reliable)
take more samples (more reliable)
repeat when the plants are bigger (less likely to miss the plant)

112
Q

Where is lipase made?

A

pancreas and small intestine

113
Q

What is the function of mitochondria?

A

where the process of aerobic respiration occurs and energy is released and transferred for use

114
Q

What is glucose in plants used for?

A
make starch for storage
make fat/oil for storage
make amino acids
make cellulose
to release energy
115
Q

Why do we not have evidence about early soft-bodied organisms?

A

lack of fossils due to soft parts decaying /

fossils destroyed due to geological activity

116
Q

What are nitrate ions used for in plants?

A

for making amino acids

117
Q

What are magnesium ions used for in plants?

A

to make chlorophyll which traps light / energy

118
Q

Why is diffusion important in animals?

A
  • takes in substances for cell processes
  • removes products from cell processes
  • e.g. for gas exchange / respiration: O2 in / CO2 out
  • e.g. food molecules absorbed: glucose, amino acids, etc
  • e.g. water absorption in the large intestine
119
Q

Why is diffusion important in animals?

A
  • takes in substances for cell processes
  • removes products from cell processes
  • e.g. for gas exchange / respiration: O2 in / CO2 out
  • e.g. food molecules absorbed: glucose, amino acids, etc
  • e.g. water absorption in the large intestine