jnjnuj Flashcards

nuhuh

1
Q

Role and structure of DNA

A

Substance that contains instructions that determine your characteristics
Deoxyribose nuclei acid, genetic material found in the nucleus in each one of your cells

Structure:
DNA -> nucleotide -> Base -> A, C, T, G

DNA is a polymer consisting of two long strands of small units that repeat throughout the structure, called nucleotides
A nucleotide is made up of a phosphate and a base attached to the sugar
Sugar and phosphates of nucleotides form the long strands
Attraction between opposite bases holds the two strands together

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2
Q

Place in size order:
Gene, chromosome, genome, DNA, nucleus, cell, nucleotide

A

Nucleotide (smallest)
Gene
DNA
Chromosome
Genome
Nucleus
Cell (largest)

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3
Q

Chromosome

A

Each long polymer of DNA

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4
Q

Nucleotides

A

The units that make up polymer of DNA

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5
Q

Each nucleotide is made up of…

A

1 phosphate
1 deoxyribose
1 organic base
O - ⭔ - ▭
Phosphate - Deoxyribose sugar - nitrogenous base

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6
Q

4 organic bases

A

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

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7
Q

What is a gene

A

Short section of DNA found upon a chromosome which codes for a specific protein

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8
Q

Protein that DNA coils around in the formation of a chromosome

A

Histone protein

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9
Q

Complementary base pairing

A

Adenine pairs with thymine
Cytosine pairs with guanine

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10
Q

Name of the structure formed by DNA, discovered by Watson and Crick in 1950s

A

Double helix

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11
Q

Who produced the first ever photograph of DNA, Photo 51, that lead to the discovery of DNA’s structure

A

Rosalind Franklin

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12
Q

Why double helix is described as being anti parallel

A

2 strands are parallel but run in opposite directions

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13
Q

Sugar phosphate backbone

A

The phosphate and deoxyribose molecules in a DNA polymer are joined
O - ⭔ - [C] ≡ [G] - ⭔ - O
/ \
O - ⭔ - [A] = [T] - ⭔ - O

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14
Q

Hydrogen bonds

A

Weak bonds formed between bases of opposing strands of DNA
O - ⭔ - [C] ≡ [G] - ⭔ - O
/ \
O - ⭔ - [A] = [T] - ⭔ - O

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15
Q

2 main sages of protein synthesis

A

Transcription
Translation

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16
Q

Where does protein synthesis take place

A

Transcription starts in nucleus and ends where mRNA strand leaves through nuclear pore towards the ribosomes
Translation happens in cytoplasm with assistance of ribosomes

17
Q

Transcription

A

DNA unzips to allow mRNA to use it as template to make a copy of a section which codes for a specific protein
Once copied, mRNA detaches and leaves nucleus and DNA zips back up
Base T is replaced by U

18
Q

Translation

A

mRNA is read by nucleus in groups of 3 codons to produce a protein
tRNA molecules are attracted to 3 complementary bases upon mRNA bringing specific amino acids with them
These join together into a chain to form a protein

19
Q

Differences between DNA and RNA

A

DNA = Deoxynucleotides
Bases A T C G
Deoxyribose sugar
Double helix structure
Cannot leave nucleus
Long polynucleotide chain
DNA is completely protected by the body from degradation
Self replicating

RNA = Ribonucleotides
Bases A U C G - THYMINE REPLACED WITH URACIL
Ribose sugar
Single strand
Can move in and out of nucleus
Short polynucleotide chain - SHORTER THAN DNA
Strands are continually made, broken down and reused
Synthesised from DNA on an as-needed basis

20
Q

Enzymes

A

Proteins
Biological catalysts - used to speed up reactions
Can’t be used up

21
Q

What molecule do enzymes bind to

A

Substrate

22
Q

Active site

A

Part of enzyme that binds to substrate
Has specific shape which is formed by way its amino acids are folded together within protein

23
Q

Lock and key hypothesis

A

Only 1 substrate will fit into active site of 1 enzyme
They must be an exact fit

24
Q

What is formed when a substrate binds to an enzyme

A

Enzyme-substrate complex

25
Q

Factors affecting enzyme activity

A

Temperature
pH
Substrate availability / concentration
Enzyme concentration

26
Q

Effect of temperature on enzyme activity

A

Rate of reaction increases due to increased kinetic energy, meaning increased number of successful collisions
Higher temperature = faster reaction
If temperature becomes too high, enzymes denature

27
Q

Denatured

A

Structure of protein that forms enzyme has been altered due to high heat or a change in pH
Change of shape affects active site
Substrate can no longer bind to enzyme

28
Q

If an enzyme is denatured, what happens to rate of reaction

A

Enzyme can no longer catalyse the reaction
Rate of reaction decreases

29
Q

How substrate concentration affects enzyme controlled reactions

A

Higher the substrate availability, higher the rate of reaction,
until all the enzyme-substrate bases are used up

30
Q

Genotype

A

All the genes you can have (blue/brown eyes)
All combinations of alleles present in an organism

31
Q

Phenotype

A

Gene that is being expressed (brown eyes only)

32
Q

Rate of reaction

A

Rate of reaction = Amount of product formed / Time

Rate of a reaction increases if:
Temperature is increased
Concentration of a dissolved reactant is increased
Pressure of a reacting gas is increased
Solid reactants are broken into smaller pieces
A catalyst is used

33
Q

DNA database pros and cons

A

+
Check on heredity / establish family tree / find relatives
Look for genetic disorders / identify health risk factors
To choose correct medication / genomics
Confirm a person’s identity

-
Avoid being identified for a crime
Avoid high insurance costs
Remain unaware of family history / genetic disorders
Dislike of sharing personal details / privacy (reasons)