Bio unit 14 Flashcards

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1
Q

variation

A

differences in the characteristics of individuals in a population

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2
Q

variation may be caused by

A
  • the genes they have inherited (genetic causes)
  • the conditions in which they have developed(environmental causes)
  • a combination of genes and the environment
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3
Q

How often do mutations occur?

A

continuously

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4
Q

Can a mutation lead to a new phenotype?

A

rarely

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5
Q

What happens if the new phenotype is suited to an environmental change?

A

there can be a rapid change in the species

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6
Q

evolution

A

change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.

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7
Q

what does the theory of evolution by natural selection state?

A

all species of living things have evolved from simple life forms that first developed more than 3 billion years ago.

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8
Q

what happens if two populations of one species become so different in phenotype that they can no longer breed to produce fertile offsrpring?

A

they have formed two new species

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9
Q

selective breeding

A

process by which humans breed plants and animals for particular genetic characteristics.

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10
Q

how long have humans been doing selective breeding?

A

thousands of years since hey first bred food crops from wild plants and domesticated animals.

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11
Q

Process of selective breeding

A
  • choosing parents with desired characteristic from a mixed population.
  • they are bred together
  • the offsrping that have the desired gene are bred together.
  • This continues over many generations until the offspring show the desired characteristic.
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12
Q

examples of useful characteritsics

A
  • disease resistance in food crops
  • Animals which produce more meat or milk
  • domestic dogs with a gentle nature
  • large or usual flowers.
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13
Q

disadvantage of selective breeding

A

can lead to ‘inbreeding’ where some breeds are particularly prone to disease or inherited defects

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14
Q

genetic engineering

A

a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.

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15
Q

how have plant crops been geneticly engineered?

A

to be resistant to diseases or to produce bigger, better fruits.

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16
Q

how have bacterial cells been geneticly engineered?

A

to produce useful substances such as human insulin to treat diabetes.

17
Q

what happens in genetic engineering?

A

Genes from the chromosomes of humans and other organisms can be ‘cut out’ and transferred to other cells or organisms

18
Q

what are crops called that have had their genes modified?

A

genetically modified (GM
) crops

19
Q

examples of GM crops:

A
  • ## crops that are resistant to insect attack or herbicides
20
Q

what are the concerns about GM crops?

A

some people feel the effects of eating GM crops on human health have not been fully explored

21
Q

What is happening with modern medical research regarding GM?

A

Exploring the possibility of genetic modification to overcome some inherited disorders.

22
Q

Steps of genetic engineering

A

-enzymes are used to isolate the required gene
-this gene is inserted into a vector, usually a bacterial plasmid or virus.
-the vector is used to insert the gene into the required cells.
- genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired chararcteristics.

23
Q

what is tissue culture?

A

using small groups of cells from part of plant to grow identical new plants.

24
Q

Why is tissue culture important?

A

For preserving rare plant species of comercially in nurseries.

25
Q

what is cuttings?

A

An older but easy method used by gardeners to produce many identical new plants from a parent plant.

26
Q

what are embryo transplants?

A

splitting apart cells from a developing animal embryo before thet become specialised. Then tranplanting the identical embryos into host mothers.

27
Q

method of adult cell cloning:

A
  • The nucleus is removed from an unfertilised egg cell.
  • The nucelus from an adult body cell, such as a skin cell, is inserted into the egg cell.
  • An electric shock stimulates the egg cell to divide to form an embryo.
    -these embryo cells contain the same genetic info as the adult skin cell.
  • When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
28
Q
A