Genetics Flashcards

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1
Q

What is the nucleus and what does it contain ?

A

The nucleus contains the
cell’s genetic material and it
acts as the ‘brain’ of the cell.

The nucleus contains DNA.

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2
Q

Zoom in on the nucleus

A

The nucleus is
surrounded by a nuclear
envelope

Chromatin is made of
DNA, arranged as
chromosomes

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3
Q

What is a gene ?

A

A gene is a section of DNA that codes for a specific protein.

It is the unit of heredity, and may be copied and passed on to the next
generation.

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4
Q

What is a chromosome ?

A

The cell’s nucleus contains chromosomes. These are long threads of DNA, each made up of many genes.

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5
Q

DNA

A

The chemical that carries the genetic code which determines the
characteristics of a living organism

- Instructions to put an organism together and make it 
  function
- DNA codes for proteins
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6
Q

Structure of DNA

A

● It is made up of two strands coiled together

● The two strands form a ‘double helix’ shape

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7
Q

DNA Bases

A
T, thymine
A, adenine
G, guanine
C, cytosine
A and T
C and G
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8
Q

DNA is a polymer and is made from…

A

DNA strands are polymers made up of lots of repeating units called ‘nucleotides’ which are monomers

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9
Q

What does a nucleotide contain…

A

Each nucleotide consists of:
One sugar molecule
One phosphate molecule
One ‘base’

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10
Q

How do the nucleotides affect the structure of DNA ?

A

They link up with other nucleotides to form a
strand.
This strand joins with another strand to form
the double-helix

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11
Q

What is the function of sugar and phosphate in the structure of DNA….

A

The sugar and phosphate molecules in the
nucleotides form a ‘backbone’ to the DNA
strands.

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12
Q

Is the order of the bases important?

A

Yes!

It determines which protein is produced
It decides the order of amino acids

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13
Q

What do amino acids do to from proteins ?

A

Amino acids join together to form proteins

The order of amino acids in a chain determines which protein is produced

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14
Q

What does each sequence of three bases code for ?

A

Each sequence of three bases codes for a
different amino acid
eg, ‘GGT’

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15
Q

Some parts of DNA do not code for proteins- what do you think they do?

A
  • Switch genes on and off

- Control whether a protein is made

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16
Q

Genes role in protein synthesis

A
  • Each gene codes for (tells the cell to make) a particular chain of amino acid
  • Genes also determine the specific order of amino acids, which determines the
    type of protein produced
  • Amino acids join together to make a proteins
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17
Q

So each small section of DNA is a small set of instructions on how to make a
specific protein…. (definition of gene)

What does this determine ?

A

This determines the type of cell that is produced.

18
Q

Mutations

A
Change the sequence of DNA
bases in a gene
- Creation of a different form of a
gene
- May create a different amino
acid and sequence of amino
acids
- Can lead to changes in the
protein coded
19
Q

If a protein that needs to fit another molecule (such as an enzyme) changes shape, what is the consequence of this?

A

Structural proteins such as collagen (a very strong
molecule) lose their strength if their shape is changed.
They become pretty useless for support and structure,
which is their function!

20
Q

ADD SICKLE CELL ANEAMIA

A

Patients with family history of breast cancer can be
tested to see if they have the faulty BRCA gene.
If found, women can receive intervention at and
early stage to prevent the cancer from occurring at
later life.

21
Q

What is a genome

A

A ‘genome’ is the fancy name for the complete set of genetic

material in an organism

22
Q

Why do you think it is important, in medicine, to

understand the genome?

A
  • Identify genes linked to disease

- Produce treatments for disease

23
Q

What is an allele ?

A

Different versions of the same gene

are called alleles.

24
Q

Why do you have two

different alleles ?

A

One from your mother
and one from your
father.

25
Q

A dominant allele….

A

Will always be expressed, even if the individual

has only one copy

26
Q

a recessive allele…

A

Only expressed if the individual has two copies of
it, and if they do not have the dominant allele
Eg- blue eyes

27
Q

Homozygous

A

Two alleles for a particular gene

that are the same.

28
Q

Heterozygous

A

Two alleles for a particular gene

are different.

29
Q

PUNETT SQUARES

A

LEARN THEM

30
Q

23rd Chromosome codes for gender…

What is the code for each gender ?

A

Females have two X chromosomes: XX

Males have two Y chromosomes: XY

31
Q

Why do the chromosomes code for gender ?

A

The Y chromosome causes
male characteristics

The XX combination allows
female characteristics to develop

32
Q

What is mitosis ?

A

A type of cell division called mitosis ensures that when a cell divides each new cell produced has the same genetic information.

33
Q

Cells divide when ?

A
  • An organism grows

* Organisms becomes damaged and needs to produce new cells

34
Q

CHECK MEIOSIS AND MITOSIS

A

CHECK CELL CYCLE

35
Q

Sexual reproductions in Plants and Animals

A

Sexual reproduction, sperm and egg in animals

Sexual reproduction, pollen and ovule in flowering plants

36
Q

How many parents are needed in sexual reproduction ?

A

Two parents are needed in sexual reproduction, and the offspring produced are genetically different to the parents.

37
Q

How many parents are needed in asexual reproduction ?

A

Only one parent is needed in asexual reproduction, and the offspring
produced are genetically identical
- Reproduction in bacteria
- Production of spores by fungi,
- Formation of tubers in potatoes and bulbs in daffodils

38
Q

Advantages of sexual reproduction…..

A
  • Variation into a population
  • Species can adapt to new
    environments
  • Disease is less likely to affect all the
    individuals in a population
39
Q

Disadvantages of sexual reproduction….

A
  • Time and energy are needed to find
    a mate
  • Not possible for an isolated
    individual
40
Q

Advantages of asexual reproduction…..

A
  • population can increase rapidly

- can exploit a suitable habitat quickly

41
Q

Disadvantages of asexual reproduction….

A
- does not lead to variation in a
population
- the species may only be suited to
one habitat
- disease may affect all the individuals
in a population