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Flashcards in U5 biology GCSE Deck (89)
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1
Q

Multicellular organisms

A

An organism which is made up of many different cell which work together. Some of the cells are specialised for different functions in the organism.

2
Q

Differentiated

A

Specialised for a particular cell

3
Q

Tissue

A

A group of specialised cells all carrying out the same function.

4
Q

Muscular tissue

A

The tissue which makes up the muscles. It can contract and relax.

5
Q

Glandular tissue

A

The tissue which makes up the glands and secretes chemicals, e.g enzymes, hormones

6
Q

Epithetical tissues

A

Tissue made up of relatively unspecialised cells which line tubes and organs of the body.

7
Q

Epidermal tissues

A

The tissue of the epidermis the outer layer of the organism

8
Q

Mesophyll tissue

A

The tissue in a green plant where photosynthesis takes place

9
Q

Xylem tissue

A

The non living transport tissue in plants which transports water around the plant

10
Q

Phloem tissue

A

The living transports in plants which carries sugars around the plant

11
Q

Digestive juices

A

The mixture of enzymes and other chemicals produced by the digestive system

12
Q

Organ systems

A

A group of organs Working together to carry out particular functions

13
Q

Small intestine

A

The region of the digestive system where most of the digestion of food takes place

14
Q

Kidney tubules

A

A structure in the kidney where substances are reabsorbed back into the blood

15
Q

Mitochondria

A

Where energy is released during aerobic respiration

16
Q

Ribosomes

A

Where protein synthesis takes place

17
Q

Diffusion

A

Is the spreading out of the particles of a fluid

18
Q

Net movement

A

The net movement into or out of cells depends on the concentration of the particles on each side of the cell membrane

19
Q

What is the concentration gradient

A

The difference between the area of high concentration and low concentration
The larger the difference in concentration the faster the rate of diffusion

20
Q

Examples of diffusion

A

Diffusion of oxygen into the cells of the body from the bloodstream as the cells respire
Diffusion of carbon dioxide into a photosynthesising plant

21
Q

The digestive system

A

Glands: pancreas and salivary glands which produce digestive juices
Stomach where digestion occurs
Liver which produces bile
Gall bladder: stores and releases bile
Small intestine absorption of soluble food occurs
Large intestine where water is absorbed.

22
Q

Equation for photosynthesis

A

Light energy
Carbon dioxide+water——– glucose+oxygen
Chlorophyll

23
Q

What are the three important limiting factors in photosynthesis

A

Light
Carbon dioxide concentration
Temperature

24
Q

How may the glucose produced by photosynthesis be used

A

Converted into insoluble starch
Used for respiration
Converted into fats and oils for storage
Used to produce cellulose which strengthens cell walls
Used to produce protein (with nitrate ions)

25
Q

Most human and animal cells have the following parts

A

A nucleus, controls cell activities
Cytoplasm, where chemical reactions take place
Cell membrane, controls the passage of substances into and out of the cell

26
Q

Plant and algal cells also have a cell wall made of cellulose. Plant cells often have

A

Chloroplasts

A permanent vacuole

27
Q

Bacterial cell consists of

A

Cytoplasm and a membrane surrounded by a cell wall

28
Q

Yeast is a single called organism they have

A

A nucleus, cytoplasm, and membrane surrounded by a cell wall

29
Q

Cells may be specialised

A

To carry out a particular function

30
Q

Dissolved substances can

A

Move into and out of cells by diffusion

31
Q

What is the equation for photosynthesis

A

Light energy

Carbon dioxide+ water—————glucose+ oxygen

32
Q

What does the iodine test show

A

By testing leaves with iodine solution we can identify the starch in the leaf and show that photosynthesis has occurred. Variegated leaves have patches of green (chlorophyll) and white (without chlorophyll) only green patches will turn the iodine solution blue-black to show that starch has been made

33
Q

Name the three most common limiting factors and describe their limitations

A

Light- a lack of light slows down the process of photosynthesis
Temperature- if it is too cold the enzymes do not work effectively and slow down photosynthesis
Carbon dioxide- if there is too little carbon dioxide then the rate of photosynthesis will slow down

34
Q

What is an independent variable

A

It is the one being tested

35
Q

What is a dependent variable

A

The one that you measure

36
Q

What are the uses of soluble glucose

A

Converted into insoluble starch for storage
Used for respiration
Converted into fats and oils for storage
Used to produce cellulose which strengthens cell walls
Used to produce proteins

37
Q

What do plant and algal need a supply of

A

Mineral ions such as nitrate ions in order to produce protein

38
Q

Protein molecules are made of

A

Long chains of amino acids

39
Q

Proteins can be

A

Muscle
Hormones
Antibodies
Catalyst

40
Q

Chemical reactions in cells are controlled by

A

Proteins called enzymes

41
Q

Enzymes are biological catalysts meaning

A

They speed up chemical reactions

42
Q

Enzymes are large proteins and the shape of the enzyme is vital as

A

The shape has an area where other molecules can fit, this is called the active site

43
Q

The substrate is

A

The substrate in a reaction can be held in the active site and either be connected to another molecule or be broken down

44
Q

Enzymes can

A

Build large molecules from many smaller ones
Change one molecule into another one
Break down large molecules into smaller ones

45
Q

Reactions take place faster when it is warmer as

A

Higher temperatures the molecules move around move more quickly and so collide with each other more often and with more energy

46
Q

If the temperature gets too hot

A

The enzymes stops working because the active site changes shape. This means the enzymes becomes denatured

47
Q

Each enzyme works best at a

A

Particular pH value, some work best in acid conditions but others need neutral or alkaline conditions

48
Q

Amylase

A

A carbohydrase is produced by the salivary glands, the pancreas and small intestine. Amylase catalyses the digestion of starch into sugars in the mouth and small intestine

49
Q

Protease

A

Is produced by the stomach, the pancreas and the small intestine. Protease catalyses the breakdown of proteins into amino acids in the stomach and small intestine

50
Q

Lipase

A

Is produced by the pancreas and small intestine. Lipase catalyses the breakdown of lipids, fats and oils, to fatty acids and glycerol

51
Q

The liver produces

A

Bile that is stored in the gall bladder. The alkaline is squirted into the small intestine and neutralises the stomach acid. Bile makes the conditions in the small intestine slightly alkaline

52
Q

What do biological detergents contain

A

Proteases and lipase that digest. They work at

53
Q

Biological detergents contain

A

Pot eases and lipase that digest food stains. They work at lower temperatures than ordinary washing powders which saves energy and money spent on electricity

54
Q

Proteases are used in industry to

A

Make baby foods by pre-digesting the

55
Q

Isomerase is used to

A

Convert starch into sugar syrup for use in foods

56
Q

What are the advantages of using enzymes

A

Enzymes in biological washing powders are very effective at removing stains such as blood, grass and gravy
Biological washing powders can be used at lower temperatures this saves energy and reduces costs
Some enzymes are used in medicine to diagnose disease

57
Q

Disadvantages of using enzymes

A

If people misuse washing powders they may have allergic reactions
Enzymes may enter water ways via the sewage system
Industrial enzymes can be costly to produce
Enzymes denature at high temperatures needed to kill pathogens in the washing
Fabrics such as wool will be digested by proteases

58
Q

Where does respiration take place

A

In the mitochondria

59
Q

What is the equation for aerobic respiration

A

Glucose+ oxygen——— carbon dioxide+water+energy

60
Q

Energy released may be used by the organism to

A

Build larger molecules from smaller ones
Enable muscle contraction in animals
Maintain a constant body temperature
Build sugars, nitrates and other nutrients into amino acids

61
Q

Why do you need to increase the rate at which oxygen and glucose reach the muscle cells for aerobic respiration

A

As you need to remove the extra waste carbon dioxide produced more quickly as well as allowing the heart rate to increase and supply more blood containing oxygen and glucose to reach the muscles

62
Q

What does glycogen do

A

It can be converted back to glucose for use during exercise

63
Q

What happens in anaerobic respiration

A

The glucose is not completely broken down in anaerobic respiration and lactic acid is produced. The less energy that is released from the glucose in anaerobic respiration. The build up of lactic acid causes muscle fatigue and blood flowing through the muscles will remove the lactic acid

64
Q

What is the extra oxygen that is needed to break down lactic acid called

A

Your oxygen debt

65
Q

What is mitosis

A

Mitosis is the result of two identical cells being produced form the original cell. The chromosomes contain the genes(alleles) which must be passed on to each new cell. A copy of the chromosomes are made before the cell divides and each one of the chromosomes goes to each new cell.

66
Q

How do gametes divide

A

Meiosis

67
Q

Sexual reproduction results in

A

Variation as the gametes from each new parent fuse when the gametes join at fertilisation a single body cell with new pairs of chromosomes is formed

68
Q

Describe meiosis

A

Before dividin a copy of each chromosome is made
The cell now divides twice to form four gametes
Each gamete has a single set of chromosomes each with a different combination of genes

69
Q

What are stem cells

A

Stem cells are unspecialised
Stem cells are found in the human embryo and in adult bone marrow
Stem cells change into all the different types of body cell (differentiated)
Layers of cells in the embryo differentiate

70
Q

Who was Mendel

A

He was a monk who worked out how characteristics were inherited
Scientists at this time did not know about chromosomes or genes

71
Q

What are chromosomes and genes

A

Chromosomes are made out of DNA which is a very long molecule with a double helix structure
Genes are short sections of DNA

72
Q

Genes controlling the same characteristics are

A

Alleles

73
Q

If an allele masks the effect of something it is

If an allele is masked by something it is

A

Dominant

Recessive

74
Q

Phenotype

A

Physical appearance of the characteristic

75
Q

Genotype

A

The genetic make up, which allele does the individual inherit

76
Q

Homozygous is when

Heterozygous is when

A

Both alleles are the same

The two alleles are different

77
Q

What is polydactyl

A

When babies are born with extra fingers or toes
Polydactyl is caused by a dominant allele
It can be inherited from one parent who has the condition.

78
Q

What is cystic fibrosis

A

Organs become clogged by thick mucus causing respiratory and reproductive problems
There is no cure most have a life span of 30
It is caused by a recessive allele so it must be inherited from both parents, parents will be carriers

79
Q

What are the arguments in favour of using embryonic stem cells

A

Offer one of the best chances if finding treatments for paralysis spinal injury Alzheimer’s and diabetes
Embryos used are usually spare embryos from infertility treatment which would be destroyed anyway
Embryos being created from adult cells for use in research, they would never become babies
Could be used to grow new tissues and organs for transplants

80
Q

Arguments against using embryonic stem cells in research

A

Very experimental and there is a risk that they may cause further problems such as the development of cancers
All embryos have the potential to become babies, therefore it is wrong to experiment
Embryos cannot give permission to be used in experiments
It takes a long time to develop any therapy time would be better spent on other possible treatments such as new drugs or using adult stem cells

81
Q

What are the ethical issues of screening

A

People in affected families can take the test and use it to decide whether or not they want the baby.
Embryos can be tested during pregnancy and may decide to abort the baby depending on the results
Some will have the embryos screened before the embryos are implanted in the women to see if they have genetic disorders

82
Q

How does sexual reproduction give rise to variation

A

As when gametes fuse one of each pair of alleles comes from each parent

83
Q

What are characteristics controlled by

A

They ses controlled by a single gene, each gene may have different forms called alleles

84
Q

What is an allele

A

An allele controls the development of a characteristic when it is present on only one of the chromosomes is a dominant allele, as well as this an allele that controls the development of characteristics only if the dominant allele is present is a recessive allele

85
Q

How is each gene coded

A

It is coded for a particular combination of amino acids which makes a specific protein

86
Q

What are fossils

A

Evidence for early forms of life come from fossils,
Fossils are the remains of organisms from many years ago they are found in rocks and are formed in various ways
The hard parts of animals that do not decay, the parts of organisms that have not decayed because one or more of the conditions needed for decay are absent, when pats of the organism are replaced by other materials as they decay, as preserved traces of organisms such as footprints and burrows

87
Q

Why do we not have evidence for all life forms

A

Many early life forms were soft bodied which means that they left fre traces behind

88
Q

How is extinction caused

A

Changes to the environment over geological time
New predators
New diseases
New competitors
A single catastrophic event e.g. Volcano/ asteroid
Through the cyclical nature of speciation

89
Q

New species arise as a result of

A

Isolation- two populations of a species become separated
Genetic variation- each population has a wide range of alleles that control their characteristics
Natural selection- in each population the alleles that control the characteristics which help the organism to survive are selected
Speciation- the population become so different that successful interbreeding is no longer possible