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Biology 🧬 > Inheritance, Variation And Evlolution 🏔 > Flashcards

Inheritance, Variation And Evlolution 🏔 Flashcards

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1
Q

What are the two types of cell division?

A

Mitosis- asexual
meiosis- sexual

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2
Q

How does meiosis occur + what does it require?

A

The sperm fuses with the egg (fertilisation)

Forming a zygote

Within the zygote, the genetic material duplicates
They line up and get pulled apart by cell fibres
causing the nucleus to divide in two
A second diffusion occurs

This leads to 4 genetically different sex cells being formed

Requires a mum and dad

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3
Q

What does mitosis require + produce?

A

1 parent
Only 1 cell division
No gamete fusion (asexual)
Offspring are clones (identical daughter cells)

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4
Q

What happens as soon as the embryo reaches a certain size in sexual reproduction?

A

Cells start to specialise

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5
Q

Advantages of sexual reproduction?

A

Artificial selection eg selective breeding
Variation of offspring - higher survival rate due to being able to adapt to changes in environment

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6
Q

Advantages of asexual reproduction ?

A

Lots of identical offspring is conditions a favourable
No mate
Faster

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7
Q

What makes a chromosome ?

A

Coil of DNA makes of genes

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8
Q

What does the genome sequencing help us understand?

A

Inherited disorders/how it can be treated

Gene identification

Human migratory history

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9
Q

What is DNA

A

a polymer (covalently bonded)made up of a double helix

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10
Q

What are the genes code made up of ?

A

Amino acids for specific proteins

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11
Q

What is the genome sequence made up of?

A

Chromosome
DNA
gene

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12
Q

What is a nucleotide made up of? What does T pair up with and what does G

A

Phosphate sugar and base
T-A
G-C

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13
Q

What are protiens ?

A

Polymers of amino acids

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14
Q

How many protiens are in humans ?

A

23

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15
Q

What does the order of the amino acids (sequence of bases) in the protein determine ?

A

The shape and function of the protein

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16
Q

What is the first stage of protein synthesis?

A

1.transcription occurs in nucleus - base sequence is copies into a complementary template called MRNA (single stranded molecule)

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17
Q

What is the second stage of protein synthesis?

A

MRNA passes through the nucleus into the cytoplasm TRANSLATION

MRNA molecule attaches to a ribosome
Amino acids attaches to ribosome on carrier molecules TRNA

Ribosome connects TRNA in right order

Once complete, the protein chain folds in its unique shape enabling it to do its job .

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18
Q

How many base codes are there?

A

3 (triplets)

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19
Q

What happened if a code
uncomplementary Changes in a protein chain? What does it lead to the active state becoming?

A

Mutation occurs resulting in a change in protein shape leading to an active site being no longer complementary to substate

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20
Q

What happens if a protein mutates at the wrong time ?

A

Uncontrolled mitosis leading to cancer

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21
Q

What is non-coding DNA?

A

DNA that does not encode protein sequences

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22
Q

What is cystic fibrosis?
What disorder is it?

A

An inherited disorder of a large build up of mucus in the lungs
Disorder of cell membranes

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23
Q

Advantages of embryo screening?

A

Financial saving of medical bills
Prevent suffering from genetic orders
Able to view future implications

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24
Q

What type of screening is embryo screening?

A

Genome

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25
Q

Disadvantages of embryo screening

A

Course cause discrimination
Expensive
Injustice (selective parents)
Unused embryos destroyed- unethical- killing human life

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26
Q

What are the men / woman genes

A

XY-men
Women-XX

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27
Q

How does selective breading take place

A

Pick 2 to be parents
Bred them
Pick offspring
Bread them
Carry on until appearance desires are met

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28
Q

What do selective breeders have to make sure? Why?

A

No unhealthy interbreeds
If so, could cause inheritary diseases

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29
Q

What is Darwin’s approach on natural selection?

A
  1. Genetic variation
    (different genes are within the population)
  2. Survival of the fittest ( alleles are favourable )
  3. Successful breading (favourable genes gets passed down to offspring)
  4. Best characterises survive
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30
Q

Criticisms of Darwin?

A
  1. Genes not discover
  2. Evidence was inconclusive
  3. Went against Christianity that god created the world
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31
Q

What was Lamark’s INCORRECT idea of evolution ? Why was he wrong?

A

Baby Giraffes gained their long neck characteristics but stretching it to eatleaves form trees, rather than it being a genetic feature this then gets passed on to offspring

THIS IS WRONG because changes of An animals lifetime do not get passes on to future generations.

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32
Q

What’s are the monomers that build up DNA called?

A

Nucleotides

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33
Q

How can a mutation in a gene result in a protein not carrying out its role correctly?

A

Mutation may carry a code for a different amino acid
Which could alter the structure of the Protein
Making it the wrong shape to transport water

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34
Q

What are fossils ?

A

Remains of organisms from millions of years ago found in rocks

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35
Q

When are the 3 ways that fossils can be formed ? + Examples?

A
  1. When parts of an organism have not decayed e.g temp too cold not enough oxygen or water
  2. When part of an organism has decayed if the parts of the organism is replaced by minerals
  3. Preserves traces of organisms eg. Footprint
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36
Q

What were some problems of older organisms forming into skeletons ?
What does it lead to scientist thinking?

A

Where soft bodies - no skeletons
So rarely formed fossils
If it did , they were crushed by the earth’s crust
This makes scientist unable to know how life on earth started

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37
Q

What are the 4 ways species can become extinct?

A
  1. Catastrophic event eg. Astroid

2.environmental changes eg. Change of weather patterns

  1. New disease or new predator
  2. New successful species evolve and competes with it for food or water
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38
Q

How many minutes can bacteria reproduce?
Why can bacteria evolve rapidly?

A

Every 30 minutes
They can evolve rapidly as the reproduce at a fast rate.

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39
Q

What antibiotic was first created ?

A

Penicillin

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40
Q

What is one common antibiotic strain of resistant bacteria?

A

MRSA

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41
Q

How do antibiotic resistant bacteria form ?
Why does the resistant strain spread?

A
  1. Genetic variation takes place , some bacterias have favourable genes due to mutations
  2. All bacteriums are killed except for the resistant one causing it to reproduce by mitosis with no competition
  3. This causes the resistant bacteria population to rise
  4. The resistant stain now spreads as people are not immune to it and no effective treatment
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42
Q

How can we reduce the amount of antibiotic resistant bacteria? (3 ways )

A
  1. Doctors show not prescribe unnecessary antibiotic inappropriately as they have no effect
  2. Patients need to complete the whole course of antibiotics making sure all bacterias have been killed and none have survived to mutate and form resistant strains
  3. Reduce the use of antibiotics in farming
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43
Q

What are the negative of scientists developing new antibiotics?

A

Takes too long + expensive
Unlikely to keep up as new bacterias emerge all the time

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44
Q

Apart from genes , what are the two main sources of evidence from evolution

A

Fossils
antibiotic resistant bacteria

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45
Q

What is a gene?

A

A section is DNA on a chromosome

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46
Q

How did Mendel investigate inheritance? What did he find out?

A

Did breeding experiments on pea plants That characteristics were not blended during inheritance

47
Q

What did Mendel say characteristics are determined by? What else sis he found out a lot characteristics?

A

By inherited units (genes) which do not change when passed in to descendants.

He found out that characteristics can be masked and then reappear in future generations (recessive)

48
Q

Give an example of a slow extinction and a rapid one

A

Slow - atmospherical
Fast- catastrophic event eg volcanic eruption

49
Q

What did Mendel experiment on? What helped him support his work?

A

Pea plants
Discovery of chromosomes
DNA discovered in 20th century

50
Q

What is a stabilising selection?
What kind of environment is it in?

A

Natural selection that favours an average phenotype in environment that do not change

51
Q

Directional selection?

A

Selection that favoured an extra am phenotype eg. Mutation

Happend aster a change in environment

52
Q

What are the two kingdoms Linnaeus split species in?

A

Plant and Animal kingdom

53
Q

What is the order of the kingdoms?

Kick
Poo
Cat
On
Fat
Geese
Sorry

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

54
Q

What is the binomial name ?
What is the classing system based on ?

A

Genus and species
Appearance of animals

55
Q

What it’s the three domain system ? Who invented it? What does it intel?

A

Woese
comparing the biochemistry between 2 organisms

  1. Primitive bacteria- extremophiles eg. Archae found Extrems conditions
  2. True bacteria found in human digestive system
  3. Eukaryota - animal, plant, protists
56
Q

Problems with evolutionary trees?

A

Cannot plot old species as fossil data is incomplete

57
Q

How do we investigate decay?

What are the two catalysts added?

A
  1. Label test tube lipase and put 5 cm of lipase solution in
  2. do the same to a new tests tube labels milk and add 5 drops cresol red using a Pipette then add 5cm^3 of milk and sodium carbonate
  3. Solution turns purple because sodium
    Carbonate is a alkaline

4.place thermometer in milk the place both test tubes in a water bath at ur initial temp 20

  1. Wait until temp of both test tubes then transferred lipase (catalyst) to the milk and stir + time
  2. Lipase starts to break down molecules in the milk releasing fatty acids causing the milk to be acidic turning the milk yellow
  3. Repeat at different temps
58
Q

What is the independent
Dependent
And control variables in the decay practical?

A

Independent- temp
Dependent- time taken for milk to turn yellow
Control-vol Of solution

59
Q

What do scientist have to avoid during the decay practical?

A

Dirty test tube will trigger the reaction before we are ready.

60
Q

State the foods chain

A

Producer - grass
Primary consumer - caterpillar
Secondary consumer - bird
Tertiary consumer - fox

61
Q

What is a biomass ?

A

The mass of a all organisms in a population

62
Q

What is the dry biomass ? Why is it’s good

A

Killing spices and drying them out this is

good as water content in each creature varies so it’s more accurate

63
Q

How many levels are there in a biomass pyramid?
What kind of organisms are on each level?
What % of light every is used for photosynthesis?

A

4
3
2
1- plants that carry out photosynthesis

only 1% of light energy is used in photosynthesis

64
Q

What is a biomass? (Def 2)

A

Living tissues of organisms including proteins lipids and carbs

65
Q

If an biomass is eaten why is only 1% absorbed ?

A

Some egested as feaces

Not all biomass is absorbed

Absorbed biomass is converted as waste Products of metabolic reactions and released eg urea

Biomass is used up for respiration to release energy and movement

Aerobic- carbon dioxide and water

66
Q

What happens during embryos embryos screening?

A

And alleles tested to see if they have any inherited alleles for inherited disorders

67
Q

What are scientists going to be able to do in the future with Embryos ?

A

May be able to correct Faulty alleles inherited disorders

68
Q

How do you know cystic fibrosis is recessive on a family tree

A

Person 11 does have cystic fibrosis However person seven or eight have cystic fibrosis

This means that the person 7 and 8 have to be carriers or cystic fibrosis and they are you must be recessive

If cystic fibrosis has a dominant allele at least one of the parents had to have cystic fibrosis in order to carry it to person 11

69
Q

What is heterozygous

A

Two different alleles so one dominant and recessive

70
Q

What is homozygous?

A

Two of the same alleles so two recessive or two dominant

71
Q

What is the genotype for somebody who has polydactyl?

A

Pp

72
Q

What is variation

A

The difference in the characteristics of individuals in a population

73
Q

What are the three main causes of variation?

A

Alleles that individuals have inherited- genetic causes - Phenotype hair colour eye colour

Environment-Colour of flowers depends on pH of the soil We are humans talk language accent

Genes and the environment- height - genetic tall alleles but diet needs lots of calcium for bones 🦴 to fully developed

74
Q

What makes genetic variation?

A

Mutations- Random changes to DNA

75
Q

What mutations have no effect at all on?

A

Phenotype but can Influencer Are you into this may lead to a person if the diet is suitable

76
Q

What can mutations lead to?

A

New Phenotype

77
Q

Why may mutations be useful?

A

Changing phenotypes may lead to benefit in environmental changes which can lead to rapid change in species

78
Q

When do scientists believe in life developed on earth?

A

3 bill years ago- simple single cells

79
Q

What is animals evolving called ?

A

Evolution by natural selection

80
Q

Explain natural selection

A

And three species every specie will have a combination of alleles that is inherited from parents

Some may have better alleles for better hearing or seeing or thicker fur

If the environment changes into colder climates rabbits with thicker fur will survive and going to reproduce passing on the favourable alleles to future generations

At the time the whole population will have thicker fur than before



81
Q

What is evolution

A

The change of the inherited characteristics of a population over time do the process of natural selection

82
Q

What happens if one species Become so different with phenotypes?

A

They can no longer interbreed and reproduce fertile offspring-They’ve become two separate species

83
Q

What are the four kinds of Selective breeding we have to know

A

Domestic dogs have been selectively bred to have a gentle nature

Food Crop to be resistant to disease

Cows to produce more meat or milk

Plants to produce large or unusual flowers

84
Q

Explain selective breeding for cows

A

We get a mixed population and get the largest female and male

Breed

We know sexual reproduction produces variation in Offspring

Get the largest melon female breed them to get them continue doing over many generations this until all of springs are large

85
Q

What are the issues with selective breeding

A

If we keep on selectively breeding closely related animals we may lead to inbreeding

Causing some animals to be prone to disease or inherited defects

86
Q

What is genetic engineering

A

We get a gene from a human and we cut it out and transfer it into bacteria

The genome of the bacteria is modified and now includes a human gene

Could be insulin

This bacteria now produces insulin which can be purified and used for type one diabetes

87
Q

How else can we use genes in plants to produce..?

A

Genetically modified crops produce larger yield and are resistant to disease or insect attack

Produce larger and better fruits

Resistance to weed killers

88
Q

What are the issues with genetically modified crops

A

People believe it may damage ecosystems or insects

and there are health effects eating 🍽 them 

89
Q

Why is genetherapy a controversial topic?

A

We don’t know how will have an effect on other genes within the embryo

90
Q

Explain the genetic engineering process

A

We identify the Gene we want to transfer

We use enzymes to isolate this gene

We transferred into plasmid- They are vectors because they transfer genes from one organism to another

The desired genes are transferred into the target organism



91
Q

What is the key facts with genetic engineering?

A

We always transfer the gene at an early stage in the organisms development

Embryo to make sure that all the cells receive the transferred Gene

So organism develops with the characteristics we want

92
Q

What is one big Advantage of cloning a plant

A

We know its exact characteristics

93
Q

How can we clone a plant (small)

A

Take cuttings-Put it in rooting powder contain hormones encourages the plants to develop roots

Producing a genetically identical clone of plant through tissue culture

94
Q

Explain how tissue culture clones plants

A

We take a plant and divided it into hundreds of tiny pieces and put it on an agar plate

Each piece contains a small number of cells

They are incubated with plant hormones

The plant hormone stimulates the part to grow and develop into a fully grown clones

Conditions must be sterile

Don’t want to introduce any microorganisms like fungi or bacteria

95
Q

Tissue culture allows us to produce what..?

A

Thousands of genetically identical plants quickly and cheaply

96
Q

How else can tissue culture be used for?

A

To preserve rare species of plants 

97
Q

How do we clone animals?

A

Start with sperm and egg cell from horses with characteristics we want

Fertilisation occurs Producing a fertilised egg

We allowed the egg to develop into early-stage embryos

It’s important that the cells in the zebras have not started to specialise- any specific kind of cell

Now get a glass rod and split the embryo in two

We transfer the two embryos into host mother 

These embryos will grow and develop into the host mothers and produce two identical offsprings

98
Q

What are the issues with Cloning animals using sexual reproduction?

A

We cannot be certain that will have characteristics we want as I’ll be a variation in the offspring 

99
Q

What is the key benefits of adult cell cloning 

A

We are cloning from the adults- Will have the characteristics that we want because it’s fully developed- cells have already been specialised

100
Q

Explain adult cell cloning?

A

Get skin cell from a animal

Take out nucleus from cell- Contains genetic information from the animal we are cloning

Get egg from female sheep. Remove nucleus from unfertilised egg cell

now has no genetic material

put the nucleus from the skin cell into the egg
now contains only genetic information from the animal we are cloning

we give the egg an electric shock because in the cell to divide forming an embryo

the genetic information is the same to the adults can sell we started with

once it has formed into a ball of cells it’s inserted into the womb of the host mother to develop

101
Q

Why does the clone look nothing like the host mother?

A

Clone does not contain any of the genetic material

102
Q

What did Lamarck think?

A

If a characteristic was regularly Use it became more developed

This strengthened the characteristic and was passed on to the offspring

103
Q

What was Wallace interested in?

A

Warning ⚠️ colours in animals

104
Q

What is speciation?

A

New species being formed

105
Q

describe how Wallace said speciation occurs 

A

Geographical barriers separating two species

Before there was a population with all of the same species that could interbreed 

Meaning any useful mutation can spread throughout the whole population

The river may change course and separate the two populations making the snails into two groups

Because they’re now separate there’s no interbreeding between the two groups

Natural selection will favour different alleles on the two sides of the island - food sources may be different

Because they’re two different groups now interbreed different mutations cannot spread between the two populations

This will lead to over generations to 2 populations of snails to change

If the river then change the course again allows it to mix the phenotypes

are so different that they cannot interbreed or reproduce To make fertile offspring

now the snails are two different species

106
Q

What do genes Determine?

A

The sequence of amino acids

107
Q

Is that are you for cystic fibrosis recessive or dominant

A

Recessive c

108
Q

is the allele for polydactyly dominant or recessive

A

Dominant P

109
Q

What did Mendel determine after testing inheritance on pea plants?

A

That characteristics are not blended into the offspring

Some characteristics can be masked and then reappear in later generations-Recessive alleles

He found out that actually
Genes determine the offspring and do not change when passed on to descendants

110
Q

What are the two ways that Mendal was proven right?

A

Scientists discovered genes on chromosomes while discovering cell division

The structure of DNA in the mid-1900s

111
Q

What are the two kingdoms that Linnaeus split Living organisms into?

A

Plant and animal kingdom

112
Q

What is the binomial name?

A

Genus and species

113
Q

What is classification based on

A

Physical features like the number of toes shape of body

114
Q

How has the classification system changed?

A

We can now use microorganisms under microscope to view their biochemistry like DNA instead physical features

Biology 🧬 (8 decks)

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