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GCSE Biology > Topic 6 > Flashcards

Topic 6 Flashcards

1
Q

What are chromosomes?

A

Really long molecules of DNA

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2
Q

What does DNA stand for?

A

deoxyribonucleic acid

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3
Q

What is deoxyribonucleic acid?

A

It’s the chemical that all of the genetic material in a cell is made up from.

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4
Q

What does DNA contain?

A

Coded information - basically all the instructions to put an organism together and make it work.

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5
Q

What does your DNA determine?

A

What inherited characteristics you have.

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6
Q

Where is DNA found?

A

In the nucleus of plant and animal cells.

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7
Q

What is DNA?

A

DNA is a polymer made up of two strands coiled together in the shape of a double helix.

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8
Q

What is a gene?

A

A small section of DNA found on a chromosome.

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9
Q

What are each gene coded for?

A

To make a particular sequence of amino acids which are put together to make a specific protein.

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10
Q

What do genes tell cells?

A

In what order to put amino acids together.

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11
Q

What is genome?

A

Just a fancy term for the entire set of genetic material in an organism.

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12
Q

How can understanding the human genome be an important tool for science and medicine?

A

1)It allows scientists to identify genes in the genome that are linked to different types of disease.
2)Knowing what genes are linked to inherited disease could help us to understand them better and could help develop effective treatments for them.
3)Scientists can look at genomes to trace migration of certain populations of people around the world.

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13
Q

What is DNA made up of?

A

Nucleotides

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14
Q

What are Nucleotides?

A

Polymers made up of lots of repeating units.

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15
Q

What does each Nucleotides consist of?

A

1 sugar molecule, 1 phosphate molecule and 1 ‘base’

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16
Q

Explain the structure of each Nucleotide?

A

The sugar and phosphate molecule in the nucleotides form a ‘backbone’ to the DNA strands. The sugar and phosphate molecules alternate. One of four different bases joins to each sugar.

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17
Q

What are the types of bases?

A

A,T,C and G

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18
Q

What does each base link to?

A

A base on the opposite strand of the helix.

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19
Q

What is complementary base pairing?

A

When A always pairs up to T and C always pairs up with G.

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20
Q

What does the order of bases in a gene decide?

A

The order of amino acids in a protein.

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21
Q

What are amino acids joined together to make?

A

Various proteins

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22
Q

What is the role of the non-coding parts of DNA?

A

To switch genes on and off, so they control weather or not a gene is expressed (used to make a protein).

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23
Q

What does the mRNA carry?

A

The code to the ribosomes.

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24
Q

Where are proteins made?

A

In the cell cytoplasm on tiny structures called ribosomes.

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25
Q

What do ribosomes use to make protein?

A

Use the code in the DNA. This is done by using a molecule called mRNA.

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26
Q

How is the molecule called mRNA made?

A

By coping the code from DNA

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27
Q

What does the mRNA do?

A

Acts as a messenger between the DNA and ribosomes - it carries the code between the two.

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28
Q

What are a few examples of protein?

A

1)Enzymes - acts as a biological catalyst to speed up chemical reactions in the body.
2)Hormones - used to carry messages around the body.
3)Structural proteins - are physically strong.

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29
Q

What are mutations?

A

A random change in an organisms DNA.

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30
Q

What do mutations change?

A

The sequence of DNA bases in a gene, which produce a genetic variant (a different form of the gene).

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31
Q

Do mutations effect proteins?

A

Most mutations have very little or no effect on the protein. Some will change it to such a small extent that its function or appearance is unaffected.

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32
Q

When do mutations effect proteins?

A

1)If the shape of an enzyme’s active site is changed, its substrate may no longer be able to bind to it.
2)Structural proteins like collagen could lose their strength if their shape is changed, making them pretty useless at providing structure and support.

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33
Q

What are examples of different types of mutations?

A

1)Insertions
2)Deletions
3)Substitutions

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34
Q

What are Insertions?

A

Insertions are where a new base is inserted into the base sequence where it shouldn’t be.

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35
Q

What does an Insertion definitely change?

A

Changes the way groups of three bases are ‘read’. which can change the amino acids they code for?

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36
Q

What can an Insertion change?

A

Can change more then one amino acid as they have a knock on effect on the bases further on in the sequence.

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37
Q

What are Deletions?

A

When a random base is deleted from the DNA base sequence.

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38
Q

How are Deletions similar to Insertions?

A

They both change the way that the base sequence is ‘read’ and have knock on effects further down the sequence.

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39
Q

What are Substitutions?

A

Substitutions mutations are when a random base in the DNA base sequence is changed to a different base

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40
Q

What is sexual reproduction?

A

Is where genetic information from two organisms is combined to produce offspring which are genetically different to either parent.

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41
Q

In sexual reproduction what does the mother and father produce?

A

gametes by meiosis

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42
Q

What do gametes contain?

A

23 chromosomes - half the number of chromosomes in a normal cell.

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43
Q

What does sexual reproduction involve?

A

The fusion of male and female gametes because there are two parents, the offspring contains a mixture off the parents’ genes.

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44
Q

In sexual reproduction why does the offspring inherit features from both parents?

A

It received a mixture of chromosomes from its mum and its dad (its the chromosomes that decide how you turn out).

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45
Q

What does asexual reproduction produce?

A

Genetically identical cells

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46
Q

What is asexual reproduction involve?

A

(there’s only one parent.) There is no fusion of gametes, no mixing of chromosomes and no genetic variations between parents and offspring so the offspring are genetically identical to the parent - they’re clones.

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47
Q

How does asexual reproduction happen?

A

By mitosis - an ordinary cells makes a new cell by dividing in two.

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48
Q

What is a clone?

A

When a new cell has exactly the same genetic information as the parent cell.

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49
Q

What are examples of things that reproduce asexually?

A

Bacteria, some plants and some animals.

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50
Q

How are gametes produced?

A

Cells dividing by meiosis

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51
Q

What happens after two gametes have fused during fertilisation?

A

The resulting new cell divides by mitosis to make a copy of itself

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52
Q

Why does mitosis repeat many times?

A

To produce lots of new cells in an embryo.

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53
Q

What happens when mitosis repeats many times to produce lots of new cells in an embryos?

A

The embryo develops, these cells then start to differentiate into the different types of specialised cell that make up a whole organism.

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54
Q

What can a variation of offspring increase?

A

Increases a chance of a species surviving a change in environment.

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55
Q

What is an advantage of sexual reproduction over asexual reproduction?

A

Offspring from sexual reproduction have a mixture of two sets of chromosomes. The organism inherits genes from both parents which produces variation in the offspring. Variation increases the chance of species surviving a change in the environment.

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56
Q

What is an advantage of asexual reproduction over sexual reproduction?

A

There only needs to be one parent this means that asexual reproduction uses less energy than sexual reproduction, because organisms don’t have to find a male. This also means asexual reproduction is faster.

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57
Q

What are some organisms that reproduce both ways?

A

1)Malaria
2)Many species of fungus
3)Loads of species of plants

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58
Q

What do chromosomes control?

A

Whether you’re male or female

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59
Q

How many pairs of chromosomes are there in every human body cell?

A

23 pairs

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60
Q

Out of the 23 pairs of chromosomes what does each chromosome control?

A

22 pairs control your characteristics and the 23rd ladled XX or XY decide your sex.

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61
Q

What chromosomes do males and females have?

A

Males have XY chromosomes and females have XX chromosomes

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62
Q

When making sperm cells what happens to the X and Y chromosomes?

A

They are drawn apart in the first diversion of meiosis. There’s a 50% chance each sperm cells gets a X or Y chromosome.

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63
Q

What do genetic diagrams show?

A

1)The possible gamete combinations.
2)The possible alleles of offspring.

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64
Q

How do you find the probability of getting a boy or girl?

A

Drawing a genetic diagram

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65
Q

How are most characteristics controlled?

A

By several genes interacting

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66
Q

What is alleles?

A

When all genes exist in different versions.

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67
Q

How are alleles represented?

A

By letters in genetic diagrams

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68
Q

How many versions (alleles) of every gene are there in your body?

A

Two - one on each chromosome in a pair

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69
Q

What is homozygous?

A

If an organism has two alleles for a particular gene that are the same then it is homozygous for that trait.

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70
Q

What is heterozygous?

A

If an organism has two alleles for a particular gene that are the different then it is heterozygous.

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71
Q

What happens when the two alleles are different?

A

Only one can determine what characteristics are present.

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72
Q

What is the dominant allele?

A

The allele for the characteristics that’s shown.

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73
Q

What are the two types of alleles?

A

Dominant and recessive

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74
Q

What must happen for an organism to display a recessive characteristic?

A

Both alleles must be recessive

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75
Q

What must happen for an organism to display a dominant characteristic?

A

The organism can be either because the dominant allele overrules the recessive one if the plant animal or organism is heterozygous.

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76
Q

What is your genotype?

A

The combination of alleles you have

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77
Q

What is your phenotype?

A

When your alleles work work at a molecular level to determine what characteristics you have.

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78
Q

What is cystic fibrosis caused by?

A

A recessive allele

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79
Q

What is cystic fibrosis?

A

A genetic disorder of the cell membrane.

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80
Q

What is the allele that causes cystic fibrosis?

A

A recessive allele, carried by about 1 person in 25.

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81
Q

How does cystic fibrosis effect the body?

A

It results in the body producing a lot of thick sticky mucus in the air passages and in the pancrease.

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82
Q

How does a child get cystic fibrosis?

A

If both parents are carries or have the disorder themselves.

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83
Q

What is polydactyly caused by?

A

A dominant allele

84
Q

What is polydactyly?

A

A genetic disorder where a baby is born with extra fingers or toes.

85
Q

What does polydactyly cause?

A

It doesn’t usually cause any other problems so isn’t life-threatening

86
Q

How do you inherit polydactyly?

A

If one parent carries the defective allele. The parent that carries the defective allele will have the condition to as the allele is dominant.

87
Q

What can embryos be used for?

A

Screened for genetic disorders.

88
Q

What happens to embryos during in vitro fertilisation (IVF)?

A

Embryos are fertilised in a laboratory and then implanted into the mother’s womb.

89
Q

What are the types of concerns surrounding embryo screening?

A

Ethical, social and economic concerns

90
Q

What are the arguments against embryonic screening?

A

1)It implies that people with genetic conditions are ‘undesirable’ - this could increase prejudice
2)There may become a point where everyone wants to screen their embryos so they can pick the most ‘desirable one’
3)Screening is expensive

91
Q

What are the arguments for embryonic screening?

A

1)It will help to stop people suffering
2)Treating disorders costs the government and taxpayers a lot of money.
3)There are laws to stop it going to far. At the moment parents cannot even select the sex of their baby unless its for health reasons.

92
Q

What did Mendel do?

A

Genetic Experiments with pea plants

93
Q

Who was Mendel?

A

An Austrian monk who trained in mathematics and natural history at the university of Vienna.

94
Q

What did Mendel note in the monastery in the mind 19th century?

A

Mendel noted how characteristics in plants were passed on from one generation to the next.

95
Q

What did Mendel show in the genetic experiment with pea plants?

A

Mendel had shown that the height characteristics in pea plants was determined by separately inherited ‘‘hereditary units’’ passed on from each parent. The ratio of tall and dwarf plants in the offspring showed that the units for tall plants, T, was dominant over the unit for dwarf plants, t.

96
Q

What is the first conclusion Mendel reached?

A

Characteristics in plants are determined by ‘‘hereditary units’’

97
Q

What is the second conclusion Mendel reached?

A

Hereditary units are passed on offspring unchanged from both parents, one unit from each parent.

98
Q

What is the third conclusion Mendel reached?

A

Hereditary units can be dominant or recessive - if an individual has both the dominant and recessive unit for a characteristic, the dominant characteristic will be expressed.

99
Q

Why did it take a while for people to understand Mendel’s work?

A

They didn’t have the background knowledge to properly understand his figures - they had no idea about genes, DNA and chromosomes.

100
Q

When did scientists realise the significant of Mendel’s work?

A

After his death

101
Q

How did knowledge of science develop in the late 1800s?

A

Scientists became familiar with chromosomes. They were able to observe how they behaved during cell diversion.

102
Q

How did knowledge of science develop in the early 20th century?

A

Scientists realised that there were striking similarities in the way that chromosomes and Mendel’s ‘‘units’’ acted. Based on this, it was proposed that the ‘‘units’’ were found on the chromosomes. We know these ‘‘units’’ as genes.

103
Q

How did knowledge of science develop in 1953?

A

The structure of DNA was determined. This allowed scientists to go out and find out exactly how genes work.

104
Q

What are variations?

A

When organisms of the same species have differences.

105
Q

What are the types of variations?

A

Genetic variation and environmental variation.

106
Q

What do different genes cause?

A

Genetic variations

107
Q

Why do plants and animals have characteristics that are in some way similar to there parents?

A

This is because and organisms characteristics are determined from the genes inherited from their parents.

108
Q

What are genes?

A

The codes inside your cells that control how you are made.

109
Q

How are genes passed on?

A

In sex cells - gametes

110
Q

Why does the combination of genes from both parents cause genetic variation?

A

Because no two of the species are genetically identical other then identical twins.

111
Q

Other then genes what are characteristics influenced by?

A

The environment

112
Q

What is environmental variation?

A

The environment causes differences between members of the same species.

113
Q

What is the theory of evolution?

A

All of today’s species have evolved from simple life forms that first started to develop over three billion years ago.

114
Q

What did Charles Darwin use to suggest the the theory of evolution by natural selection?

A

The observations he made on a huge round-the-world-trip, along with experiments, discussions and new knowledge of fossils and geology.

115
Q

What did Darwin conclude in the idea ‘survival of the fittest’?

A

The organisms with the most suitable characteristics for the environment would be more successful competitors and would be more likely to survive.

116
Q

What are the organisms that survive in ‘survival of the fittest’ more likely to do?

A

Reproduce and pass on the genes for the characteristics that made them successful to their offspring.

117
Q

What are the organisms that are less well adapted less likely to do?

A

Survive and reproduce, so they are less likely to pass on their genes to the next generation.

118
Q

Over time how do the beneficial characteristics evolve?

A

They become more common in the population and the species change.

119
Q

Why was Darwin’s theory not perfect?

A

Because the relevant scientific knowledge wasn’t available at the time, he couldn’t give a good explanation for why new characteristics appeared or exactly how individual pass

120
Q

What are phenotypes controlled by?

A

Genes

121
Q

How do new phenotypes arise?

A

Because of genetic variants produced by mutations.

122
Q

What is the development of new species called?

A

speciation

123
Q

What is speciation?

A

When the phenotype changes so much over a long period of time because of natural selection that a completely new specie is formed.

124
Q

When does speciation happen?

A

When populations of the same specie change enough to become reproductively isolated.

125
Q

What does reproductively isolated mean?

A

This means that they can’t interbreed to produce fertile offspring.

126
Q

What is extinction?

A

When no individuals of offspring remain.

127
Q

Why do species become extinct?

A

1)The environment changes too quickly
2)A new predator kills them all
3)A new disease kills them all
4)They can’t compete with another (new) specie for food
5)A catastrophic event happens that kills them all

128
Q

How was Darwin’s theory against common religious beliefs?

A

It was the first plausible explanation for the existence of life on earth without the need for s ‘‘creator’’ (god)

129
Q

What did Lamarck argue?

A

That the changes an organism acquires during its lifetime will be passed on to its offspring

130
Q

Why do scientists develop different hypotheses?

A

They have different beliefs or have been influenced by different people or they just think differently.

131
Q

How do you find out whose hypothesis is right?

A

Find evidence to support or disprove each one.

132
Q

Why was Lamarck’s hypothesis eventually rejected?

A

Because experiments didn’t support his hypothesis.

133
Q

How did the discovery of genetics support Darwin’s idea?

A

Because it provided an explanation of how organisms born with beneficial characteristics can pass them on.

134
Q

How did fossils of different ages support Darwin’s idea?

A

This allows you to see how changes in organisms developed slowly over time.

135
Q

What is selective breeding?

A

When humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population.

136
Q

Why are organisms selectively bred?

A

To develop features that are useful or attractive.

137
Q

What organisms are selectively bred?

A

1)Animals that produce more meat or milk
2)Crops with disease resistance
3)Dogs with good gentle temperament
4)Decorative plants with big or unusual flowers

138
Q

What is the basic process involved in selective breeding?

A

1)From your existing stock, select which ones have the characteristics you’re after
2)Breed them with each other
3)Select the best of the offspring, and breed them together
4)Continue this process of several generations, and the desirable trait gets stronger and stronger. Eventually, all the offspring will have the characteristics.

139
Q

In agriculture what can selective breeding be used for?

A

To improve yields

140
Q

What is the main problem with selective breeding?

A

It reduces the gene pool

141
Q

What is the gene pool?

A

The number of different alleles (forms of gene) in a population

142
Q

What is inbreeding?

A

The farmer keeps breeding the ‘‘best’’ animals or plants - which are all closely related.

143
Q

What can inbreeding cause?

A

Health problems because there’s more chance of the organisms inheriting harmful genetic defects when the gene pool is limited.

144
Q

Why can a new disease cause?

A

Serious problems because there’s not much variation in the population.

145
Q

What is the basic idea of genetic engineering?

A

To transfer a gene responsible for a desirable characteristic from one organism’s genome into another organism, so that it also has the desired characteristic.

146
Q

What happens to a useful gene?

A

It is isolated (cut) from one organism’s genome using enzymes and is inserted into a vector.

147
Q

What is the vector that the useful gene is inserted into?

A

The vector is usually a virus or a bacterial plasmid, depending on the type of organism that the gene is being transferred to.

148
Q

What happens to the gene when the vector is introduced to the target organism?

A

The useful gene is inserted into its cells.

149
Q

What do scientists use genetic engineering on?

A

1)Bacteria
2)Genetically modified (GM) crops
3)Sheep

150
Q

How has bacteria been genetically engineering?

A

To produce human insulin that can be used to treat disease

151
Q

How has genetically modified crops been genetically engineering?

A

They have had their genes modified

152
Q

How has sheep been genetically engineering?

A

To produce substances, like drugs in their milk that can be used to treat human disease.

153
Q

Why is genetic engineering a controversial topic?

A

There are worries that the long-term effects of genetic engineering might accidentally create unplanned problems, which could get passed on to future generations.

154
Q

What are the pros of GM crops?

A

1)Some say the growing number of GM crops will affect the number of wild flowers - reducing farmland biodiversity
2)The characteristics chosen for GM crops can increase the yield, making food.
3)Gm crops could be engineered to contain the nutrients missing for people in developing nations.
4)GM crops are already being grown in some places, often without any problems.

155
Q

What are the cons of GM crops

A

1)Not everyone is convinced they are safe and some people are concerned that we might not fully understand the effects of eating them on human health.
2)A big concern is that transplanted genes may get out into the natural environment.

156
Q

How can plants be cloned?

A

By tissue culture and from cuttings

157
Q

What is tissue culture?

A

This is where a few plant cells are put in a growth medium with hormones, and they grow into new plants - clones of the parent cell.

158
Q

How can you make animal clones?

A

Using embryo transplants

159
Q

What is the first step of animal cloning using embryo transplants?

A

1)Sperm cells are taken from a prize bull and egg cells are taken from a prize cow. The sperm are then used to artificially fertilise an egg cell. The embryo that develops is then split many times (to form clones) before any cells become specialised.

160
Q

What is the second step of animal cloning using embryo transplants?

A

2)These cloned embryos can then be implanted into lots of other cows where they grow into baby calves (which will all be genetically identical to each other).

161
Q

What is adult cell cloning?

A

Another way to make a clone

162
Q

What does adult cell cloning involve?

A

1)Taking an unfertilised egg cell and removing its nucleus. The nucleus is the removed from an adult body cell and is inserted into the ‘empty’ egg cell.
2)The egg cell is the stimulated by an electric shock - this makes it divide like a normal embryo
3)When the embryo is a ball of cells, it’s implanted into the womb of an adult female. It grows into a genetically identical copy (clone) of the original adult body cell as it has the same genetic information.

163
Q

What are the many issues surrounding cloning?

A

1)You can get a reduced gene pool.
2)Cloned animals may not be as healthy as normal ones.
3)Some people worry that humans may be cloned in the future.

164
Q

What are the advantages of cloning?

A

1)Cloning quickly gets you lots of ‘‘ideal’’ offspring.
2)The study of animal clones could lead to a greater understanding of the development of the embryo, and of ageing and age related disorders.
3)Could help preserve endangered species.

165
Q

What are fossils?

A

Fossils are the remains of organisms from many thousands of years ago, which are found in rocks.

166
Q

What are the different ways in which fossils form in rocks?

A

1)From gradual replacement by minerals
2)From casts and impressions
3)From preservation in places where no decay happens

167
Q

What are examples of things which decay easily ad can last a long time when buried?

A

Teeth, shells and bones.

168
Q

How do fossils form in rocks from gradual replacement by minerals?

A

They’re eventually replaced by minerals as they decay, forming a rock like substance shaped like the original hard part.

169
Q

What happens to the fossil from gradual replacement by minerals when the surrounding sediments also turn to rock?

A

The fossil stays distinct inside the rock and eventually someone digs it up.

170
Q

How do fossils form in rocks from casts and impressions form fossils?

A

Fossils are formed when an organism is buried in a soft material like clay. The clay later hardens around it and the organism decays, leaving a cast of itself.

171
Q

What are impressions left from?

A

Things like footprints which can also be pressed into these materials when soft.

172
Q

Can fossils form in amber and tar pits?

A

There ‘s no oxygen or moisture so decay microbes can’t survive.

173
Q

Can fossils form in glaciers?

A

It’s too cold for the decay microbes to work.

174
Q

Can fossils form in peat bogs?

A

Peat bogs are too acidic for decay microbes.

175
Q

What do fossils show?

A

How much or how little different organisms have changed (evolved) as life has developed on earth.

176
Q

What is speciation?

A

Speciation is the development of a new species

177
Q

What is species?

A

A species is a group of similar organisms that can reproduce to give fertile offspring.

178
Q

When does speciation occur?

A

When the populations of the same species become so different that they can no longer successfully interbreed to produce fertile offspring.

179
Q

What is isolation?

A

Where populations of a species are separated.

180
Q

Why does isolation happen?

A

Due to physical barriers

181
Q

When a specie is isolated what can each population show?

A

Genetic variation because they have a wide range of alleles.

182
Q

When a specie is isolated what is more likely to happen in each population?

A

Individuals with characteristics that make them better adapted to their environment have a better chance of survival and are more likely to breed successfully.

183
Q

What alleles are more likely to be passed on to the next generation?

A

The alleles that control the beneficial characteristics.

184
Q

What are the steps in which isolation and natural selection can lead to speciation?

A

1)Two populations of the same species
2)Physical barrier separates populations
3)Populations adapt to new environments
4)Development of new species

185
Q

Who was Alfred Russel Wallace?

A

A scientist working at the same time as Charles Darwin.

186
Q

What did Alfred Russel Wallace work on?

A

Idea of speciation.

187
Q

How was Alfred Russel Wallace observations beneficial?

A

Contributed to how we understand speciation today.

188
Q

During his career what did Alfred Russel Wallace come up with?

A

The idea of natural selection and published work on the subject with Darwin in 1858

189
Q

What did Alfred Russel Wallace’s idea promote Darwin to do?

A

Publish ‘on the origin of species’ in 1859

190
Q

What can evolve quickly and become antibiotic resistance?

A

Bacteria

191
Q

What can random mutations in bacteria lead to?

A

Can lead to changes in bacteria’s characteristics. This can lead to antibiotic resistant strains forming as a gene which becomes more common in the population because of natural selection.

192
Q

How are Bacterium’s different to bacteria?

A

For Bacterium the ability to resist antibiotics is a big advantage. It’s better to be able to survive, even in a host who’s being treated to get rid of the infection, and so it survives for longer and reproduces many more times. This increases the population size for antibiotic resistant strains.

193
Q

Why are antibiotic resistant strains a problem for people who get infected with these bacteria?

A

They aren’t immune to these new strains and there is no effective treatment. This means that the infection easily spreads between people.

194
Q

What is MRSA?

A

MRSA is a relatively common ‘superbug’ that’s really hard to get rid of. It often affects people in hospitals and can be fatal if it enters the bloodstream.

195
Q

Why is antibiotic resistance getting worse?

A

Because of the overuse and inappropriate use of antibiotics.

196
Q

What is classification?

A

Classification is organising living organisms into groups.

197
Q

What was the traditional form of classification proposed in 1700’s by Carl Linnaeus?

A

Groups living things according to their characteristics and the structures that make them up.

198
Q

In the Linnaean system what are living things divided into?

A

Divided into kingdoms

199
Q

In the Linnaean system what are the kingdoms subdivided into?

A

Smaller and smaller groups -
Phylum ,Class, Order, Family, Genus, Species.

200
Q

What did Carl Woese propose in 1990?

A

The three domain system. Using evidence gathered from new chemical analysis techniques such as RNA sequence analysis, he found that in some cases, species thought to be closely related in traditional classification systems are in fact not as closely related as once thoght.

201
Q

What is the three domain system?

A

When organisms are split into 3 large groups called domains.

202
Q

What are the three domains from the three domain system?

A

1)Archaea - Organisms in this domain were once thought to be primitive bacteria, but they’re actually a different type of prokaryotic cell. They were once founded in extreme places such as hot springs and salt lakes.
2)Bacteria - This domain contains true bacteria. Although they often look similar to Archaea, there are lots of biochemical differences between them.
3)Eukaryota - This domain includes a broad range of organisms including fungi, plants, animals and protists.

203
Q

How are organisms named?

A

According to the Binomial system.

204
Q

What is every organism given in the binomial system?

A

Two part Latin names. The first part refers to the genus that the organism belongs to. This gives you information on the organisms ancestry. The second part refers to the species.

205
Q

What do evolutionary trees show?

A

-Evolutionary relationships
-How scientists think different species are related to each other.
-common ancestors between species

GCSE Biology (7 decks)

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