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Biology_Paper_2 > Inheritance, Variation, Evolution > Flashcards

Inheritance, Variation, Evolution Flashcards

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1
Q

Describe asexual reproduction?

A

●One parent only
●No fusion of gametes so no mixing of genetic info
●Production of genetically identical offspring (clones)
●Mitosis

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2
Q

How do strawberry plants produce asexually?

A

Seed out long shoots called runners which touch the ground and grow a new plant

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3
Q

How do daffodils asexually reproduce?

A

Daffodils produce alot of smaller bulbs which grow into new plants

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4
Q

How does fungi asexually reproduce?

A

By spores

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5
Q

How does malarial protists reproduce asexually when they are in the human host

A
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6
Q

Do gardeners use asexual reproduction?

A

Yes, to produce large numbers of identical plants

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7
Q

What does sexual reproduction involve?

A

Fusion (joining) of male and female gametes:
●Sperm and egg cells in animals
●Pollen and egg cells in flowering plants

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8
Q

What does sexual reproduction create in terms of offspring?

A

The mix of genetic information produces variation in offspring

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9
Q

What process does the formation of gametes in sexual reproduction involve?

A

Meosis

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10
Q

Describe the process of meiosis?

A

1) Cells with two pairs of chromosomes (diploid cell)
2) Each chromosome replicates itself
3) Chromosomes part and move to opposite poles/sides
4) Cells divide for first time
5) Copies now separate and 2nd cell division takes place
6) Four haploid Cells (gametes) each with half thd number of chromosomes of the parent cell

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11
Q

What happens to a cell during meiosis?

A

●Copies of genetic info are made
●Cell divides twice to form four gametes with a single set of chromosomes
●All gametes are genetically different

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12
Q

Why is meiosis important?

A

Halves the number of chromosomes in gametes, so fertilisation can restore the full number of chromosomes, once fertilised the resulting egg divides rapidly by mitosis and cells become specialised

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13
Q

How many chromosomes are in a sperm and egg cells?

A

Contain single chromosomes (1 of each chromosome instead of the normal 2)

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14
Q

What part of the body does meosis take place in?

A

The reproductive organs (testes in males, ovaries in females)

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15
Q

What are some advantages of sexual reproduction?

A

●Produces offspring variation
●If environment changes, variation means some organisms will survive
●Selective breeding in plants and animals
●Increases food production

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16
Q

What are some advantages of asexual reproduction?

A

●Only one parent needed
●More time and energy efficient, don’t need to find a mate
●Faster than sexual
●Produced to make best use of good conditions

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17
Q

How do plants produce sexually and asexually?

A

●Produce seeds sexually (insects carry pollen from a male part to a female part)
●Reproduce asexually using bulbs and runners

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18
Q

How does malaria produce sexually and asexually ?

A

●Malaria produces sexually in mosquito
●Asexually in humans (multiplies continously on its own)

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19
Q

When organisms have a choice which sort of way to reproduce, what do they chose when conditions are good?

A

Asexually

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20
Q

When organisms have a choice which way to reproduce, what do they chose when conditions are getting worse?

A

Sexually, fir example when there is lack of food or drop in temp (they can’t keep reproducing on there own so find something else with some food so they can produce together as the don’t have enough energy on their own)

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21
Q

What does DNA contain?

A

Structures called chromosomes

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22
Q

What is a gene?

A

Small section if DNA on a chromosome

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23
Q

What does each gene code for?

A

A particular sequence of amino acids which make a specific protein

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24
Q

What is the genome?

A

All the genetic material found in an organism

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25
Has whole genome been studied?
Yes, it has important uses for doctors and scientists
26
Now the whole genome has been studied how does this help doctors?
●Doctors can search for genes linked to different types of disorders
27
Now the whole genome has been studied how does this help scientists?
●Help scientists understand cause of inherited diseases and how to treat them ●scientists investigate how humans have changed over time
28
What is DNA made up of?
A polymer made up of repeating units called nucleotides
29
What does each nucleotide consists of?
●A sugar ●A phosphate ●One of the four bases: A,C,G or T
30
How are nucleotides joined together?
Joined together to form long strands
31
How does each nucleotide molecule make a double helix?
Each molecule has two alternating sugar and phosphate strands which are twisted to form a double helix, this is the outside of the double helix structure called the sugar phosphate backbone
32
What is attached to the sugar phosphate backbone?
One of the four bases
33
What three types of molecule make up DNA?
●Sugar ●Phosphate ●Base
34
What did Gregor Mendel discover?
That characteristics are determined by 'units' that are inherited and don't blend together
35
Why was the importance of Mendels discovery not recognised?
●A monk so worked in a monastery not a scientist at uni ●Didn't publish his work
36
Can some characteristics be controlled by a single gene?
Yes,
37
Give an example in humans and animals where characteristics are controlled by a single gene?
Fur colour in mice Colour blindness in humans
38
What do many genes have?
Different forms called alleles (an alternative form of a particular gene)
39
What is an allele?
An alternative form of a particular gene
40
How many alleles does each person have?
Two alleles for each gene
41
A person has two alleles for each gene where do the alleles come from?
One alleles from mother One allele from father
42
What is a genotype?
Combination of alleles in a gene. For example bb
43
What is phenotype?
How alleles are expressed (what characteristics appear)
44
What does a dominant allele do in terms of characteristics?
Dominant allele always expressed (even if only one copy is present)
45
What does a recessive allele do in terms of characteristics?
The allele is only expressed if two copies present (no dominant allele)
46
What does homozygous mean?
Two alleles present are the same. For example BB,bb
47
What is heterozygous?
Alleles are different. For example Bb
48
How many genes controll characteristics?
Many genes that work together
49
What is monohybrid inheritance?
When only one gene is involved
50
How can we predict monohybrid cross outcomes?
Genetic diagrams / punnet squares
51
What have scientists used fossils for?
To look at how organisms have changed over long time periods
52
Why are there gaps in fossil records?
●Many early forms were soft bodied so left very few traces behind ●Traces left may have been destroyed by geological activity (like earthquakes)
53
How can the development of antibiotic resistant bacteria be explained by the theory of natural selection?
■Bacteria can evolve rapidly dye to fast reproduction rate ■Mutatee bacteria can be resistant to antibiotics and not killed ■These bacteria survive and reproduce so resistant strain develops
54
What is a monohybrid cross?
Crosses of single gene combinations
55
How do genetic disorders occur?
Genetic disorders are inherited and caused by inheritance of certain alleles
56
How is polydactyl inherited?
Dominant allele
57
How is cystic fibrosis inherited?
Recessive allele
58
What is polydactyly?
Extra fingers or toes
59
What is cystic fibrosis?
A disorder of cell membranes
60
What are the female sex chromosomes?
XX
61
What sex chromosomes makes a male?
X and a shorter Y chromosome
62
What chromosomes do offspring inherit from mum and dad?
♡One sex chromosome from mum (X) ♡One sex chromosome from dad (X or Y)
63
What is variation?
Differences in characteristics of individuals in a population
64
Along with Dareins theory what else provides evidence for evolution?
Fossils
65
What are fossils?
Remains of organisms from hundreds of thousands of years ago found in rocks
66
Name the 4 ways fossils are formed?
●Hards parts of animals which don't decay easily ●Parts of organisms that haven't decayed due to more than one of the conditions needed for decay are absent ●Parts of organisms replaced by other materials as they decay ●Preserved traces of organisms like footprints
67
How is decay to form fossils of an organism affected by weather?
Parts of organisms that haven't decayed due to more than one of the conditions needed for decay are absent
68
What is variation due to differences in?
-Genes inherited (genetics) -Conditions individuals have developed in (environmental) -Combination of both
69
What do mutations create?
New alleles
70
What happens when a mutation affects a phenotype?
Mutation may produce a phenotype that gives an organism a great survival advantage
71
Do mutations affect a phenotype?
No, but it happens very rarely
72
Define evolution?
The gradual change in inherited characteristics of a population over time,leads to a formation of a new species
73
What leads to a formation of a new species?
Evolution
74
What did Darwin observe in terms of offspring?
Organisms often produce large numbers of offspring
75
What did Darwin observe in terms of population size?
Populations usually stay about the sane size
76
What did Darwin observe in terms of differences?
Organisms are slightly different/ show variation
77
What did Darwin observe in terms of inheritance?
Characteristics are inherited
78
What did Darwin use his observations to conclude in terms of exsistence?
Struggle for exsistence
79
What did Darwin use his observations to conclude about organism survival?
More organism are born than can survive
80
What did Darwin use his observations to conclude about breeding?
The ones that survive and breed are the best suited to the environment
81
What did Darwins observations conclude about characteristics?
Organisms pass characteristics onto their offspring
82
What did Darwin use his observations to conclude about characteristic change?
Over long period of time, characteristics of populations change
83
What was the name of a man who came up with a similar idea to Darwin?
Alfred Russel Wallace
84
What did Wallaces theory make Darwin do?
Made Darwin realise to publish his findings
85
What was the name of Darwins book?
On the origin of species. Published in 1859
86
Why did it take people a while to accept Darwins theory?
-Challenged that God made all organisms on earth -Not enough evidence to convince scientists -Mechanisms (how it works) of inheritance and variation not known until 50 years after theory was published
87
What is lamarcks idea of how giraffes necks developed?
Lamarck=necks of giraffes stretched during their lifetime, this characteristic was passed on to next generation
88
What is Darsins idea of how giraffes necks developed?
Darwin=giraffes that had longer necks could reach more food in trees so more likely to survive and reproduce
89
Why are there only a few blood types?
Controlled by a single gene
90
Why is there a range of heights?
Height is a combination of genes and environment
91
Who was Lamarck?
Came up with another idea of evolution
92
What was Lamarcks theory of evolution?
Idea that changes occur in an organism during its lifetime can be inherited, know now that this inheritance can't occur
93
What is a use of selective breeding in crops?
Produce food crops from wild plants
94
What is a use of selective breeding in animals?
Produce domesticated animals from wild animals
95
Define selective breeding?
Process by which humans breed plants and animals with particular, desirable characteristics
96
What is the first and second step of selective breeding?
1) Choose parents with best desired characteristics 2) Breed them together
97
What are the 3rd and 4th step of selective breeding?
3)From offspring choose those with desired characteristics and breed 4)Continue over generations
98
What are some characteristics that are selected for selective breeding?
☆Disease resistance in food crops ☆Animals that produce more milk or meat ☆Domestic dogs that are gentle ☆Large or unusual flowers
99
What can be a problem with selective breeding?
Can lead to inbreeding
100
What is inbreeding?
Where some breeds are prone to disease or inherited defects
101
What is genetic engineering?
Process of moving a gene from one organism to another
102
How are ways plants have already been already genetically engineered ?
•To be resistant to disease,insects,herbicide attack •To produce bigger, better fruits
103
What is a herbicide attack?
Undesired effect due to coming in contact with a weed killer pesticide
104
What is the name given to crops that have had their genes modified?
Genetically modified (GM) crops
105
Concerns about GM crops?
*Long term effects on insects and wildflowers *Genes for insect resistance may enter wild *Effect on human health
106
How has genetically engineering been beneficial for humans?
Fungi/bacterial cells have been genetically engineered to produce insulin to treat type 1 diabetes
107
What are the 3 stages of producing genetically engineered insulin?
1-Human insulin gene taken from part of human chromosome 2-Ring of bacterial DNA (plasmid) cut open 3-Human insulin gene inserted into plasmid
108
Define clone?
Genetically identical
109
How are clones produced?
Asexually
110
How does cloning work with plants?
Produced from cuttings or tissue culture (small groups of cells to grow new plants)
111
What are the 5 steps of cloning?
1-Nucleus taken from skin cell of organism to be cloned 2-Nucleus inserted into egg cell 3-Electric shock causes cell to split and develop 4-Developing cells inserted into surrogate mother 5-Clone is born
112
What are the 4 stages to cloning a plant with cuttings?
1-Select plant 2-Take cuttings 3-Place cuttings in soil and dampness 4-Genetically identical plant devdlops
113
What are is Carl linneaus classification?
Kingdom Phylum Class Order Family Genus Species
114
How are organisms named?
By the binomial system
115
What is the binomial system?
Method of naming organism by using their genus and species
116
Give an example of the binomial system?
Name for lion is pathera leo and name for tiger is panthera tigris. Same genus different species
117
Define genus?
Group of closely related species
118
Why is there new models of classification?
●Microscope improvement ●Biochemical processes (how body converts food into energy etc) better understoood
119
What system had been developed due to evidence from genetic studies?
A three-domain system
120
Who developed the three-domain system?
Carl Woese
121
Who created classification?
Carl Linneaus
122
What 3 categories have organisms been divided into in the three-domain system?
Archae,bacteria,eukaryota
123
According to the three-domain system what is archae?
Primitive bacteria, live in extreme environments
124
According to three-domain system what is bacteria?
True bacteria, have flagella
125
According to the three-domain system what is eukaryota?
Protists,fungi,plants,animals
126
What are some causes of extinction?
☆Humans (over hunting) ☆Changes to environment ☆New predators ☆New disease ☆Catastrophic event (🦕🦖) ☆New,more successful competitors
127
What are evolutionary trees?
Method used by scientists to show how they think organisms are related
128
What do scientists use current classification data for?
For fossil data and living organisms to find out more about extinct organisms
129
What is speciation?
•Lowest level of classification system •Members similar enough to breed and produce fertile offspring
130
What was another theory Alfred Russel Wallacs came up with other than evolution?
Speciation-how species develop
131
What is speciation?
How species develop
132
What are the 4 stages of speciation by Alfred Russel Wallace?
1)populations become physically isolated from each other e.g ocean 2)genetic variation 3)natural selection is different in the two species 4)populations become so different that they can't breed
133
How do scientists know that two organisms have become different species?
They can no longer breed
134
What does the name felis catus for domestic cats tell us about how they are classified?
Genus=Felis Species=Felis catus

Biology_Paper_2 (3 decks)

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