B1.2 - What happens in cells? Flashcards

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1
Q

What does DNA stand for?

A

DNA is deoxyribose nucleic acid

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1
Q

What is DNA ?

A

It is the genetic material found within the nucleus of every one of your cells.

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2
Q

State the role of DNA in the body ?

A

DNA is the substance that contains all the instructions that determine your characteristics

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3
Q

What units/ monomers make up the polymer DNA?

A

Nucletoides

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4
Q

What is a nucleotide composed of ?

A

1 phosphate, 1 deoxyribose sugar + 1 organic base

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5
Q

What are the 4 organic bases called ?

A

Thymine, Adenine, Guanine + Cytosine

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6
Q

What is a gene ?

A

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

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7
Q

What it complementary base pairing?

A

Adenine - Thymine
Cytosine - Guanine

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8
Q

What is the name of the structure formed by DNA, as discovered by Watson and Crick in the 1950s ?

A

Double Helix

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9
Q

Who produced the first ever photograph of DNA, ‘photo 51’, that led to the discover of DNA’s structure ?

A

Rosalind Franklin

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10
Q

Why is the double helix described as being ‘anti-parallel’?

A

The two strands which form DNA are parallel but run in opposite directions

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11
Q

Where are the phosphate and deoxyribose molecules in a DNA polymer joined from ?

A

The sugar-phosphate backbone

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12
Q

What is the name of the weak bonds formed between bases of opposing strands of DNA?

A

Hydrogen bonds

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13
Q

What is each long molecule. of DNA called ?

A

Chromosome

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14
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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15
Q

Name the tow stages of protein synthesis ?

A

Transcription Translation

16
Q

Where does protein synthesis take place

A

A
Transcription - starts in the nucleus, and ends when the mRNA strand leaves through the nuclear pore to towards the ribosomes Translation - In the cytoplasm with the assistance of ribosomes

17
Q

Define transcription

A

The process by which DNA unzips to allow mRNA to use it as a template to make a copy of a section which codes for a specific protein. Once copied the mRNA detaches and leaves the nucleus and the DNA zips back up.

18
Q

Define translation.

A

The process by which mRNA is read by the nucleus in groups of three ‘codons’, to produce a protein. During translation tRNA molecules are attracted to their complementary bases upon the mRNA bringing specific amino acids with them that join together into a chain to form a protein.

19
Q

What are the key differences between DNA and RNA?

A

DNA

Deoxyribonucleotides
Bases: A, T, C, G
Sugar: deoxyribose
Double helix
Can not leave the nucleus
Long polynucleotide chain
DNA is completely protected by the body from degradation.
Self-replicating
RNA

RNA

Ribonucleotides
Bases: A, U, C, G
Sugar: ribose
Single strand
RNA can move in and out of the nucleus.
Short polynucleotide chain
Strands are continually made, broken down and reused
Synthesized from DNA on an as-needed basis.

20
Q

What are enzymes?

A

Proteins which act as biological catalysts - meaning they speed up reactions without being used up in the process.

21
Q

What is the name of the molecule that an enzyme binds to?

A

Substrate

22
Q

What is an ‘active site’?

A

An active site is part of an enzyme that binds to the substrate. It has a specific shape which is formed by the way its amino acids are folded togther within the protein.

23
Q

This hypothesis states that only one substrate will fit one enzyme, and that they must be an exact fit.

A

Lock and key hypothesis

24
Q

Q
What is formed when a substrate binds to an enzyme

A

Enzyme-substrate complex

25
Q

State the factors affecting enzyme activity?

A

Temperature
pH
Substrate availability/concentration
Enzyme concentration

26
Q

What is the affect of temperature upon enzyme activity

A

The rate of reaction increases as increase kintetic energy, means increased number of successful collisions.
The higher the temperature, the faster the reaction
If the temperature becomes too high the enzyme denatures

27
Q

What does ‘denatured’ mean?

A

The structure of the protein that forms the enzyme has been altered due to high heat or a change in pH.
The change in shape affects the active site
The substrate can no longer bind with the enzyme

28
Q

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

A

As the enzyme can no longer catalyse the reaction, the rate of reaction decreases.

29
Q

How does substrate concentration affect enzyme-controlled reactions?

A

The higher the substrate availability the higher the rate of reaction until all the enzyme-substrate bases are used up.