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WJEC Biology AS Level - Marianne Izen - 2nd Edition > 95 WJEC Biology AS Level - Marianne Izen - 2nd Edition (Nucleic Acids And Their Functions) > Flashcards

95 WJEC Biology AS Level - Marianne Izen - 2nd Edition (Nucleic Acids And Their Functions) Flashcards

1
Q

What are nucleic acids?

A

Nucleic acids are polymers, made of monomers called nucleotides.

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2
Q

What is a polynucleotide?

A

A molecule containing many nucleotides is a polynucleotide.

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3
Q

How long can a polynucleotide be?

A

Polynucleotides may be millions of nucleotides long.

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4
Q

What are the components of a nucleotide?

A

A nucleotide has three components:

  1. A phosphate group
  2. A pentose sugar
  3. An organic base
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5
Q

How are the three components of nucleotides combined?

A

They are combined by condensation reactions:

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6
Q

Tell me about the structure of the phosphate group?

A

The phosphate group has the same structure in all nucleotides.

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7
Q

What is the pentose in RNA?
What is the pentose in DNA?

A

The pentose is ribose in RNA
The pentose is deoxyribose in DNA.

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8
Q

What is the other name for the organic base?

A

Nitrogenous base

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9
Q

What are the groups of organic bases?

A

There are two groups of organic bases:

  1. Pyrimidine bases
  2. Purine bases
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10
Q

What are the pyrimidine bases?

A

The pyrimidine bases are

  1. thymine
  2. cytosine
  3. uracil
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11
Q

What are the purine bases?

A

The purine bases are

  1. adenine
  2. guanine.
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12
Q

What makes changes in biological systems?

A

In biological systems it is chemical energy that makes changes.

This is because chemical bonds must make or break for reactions to happen.

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13
Q

How do autotrophic organisms get chemical energy?

A

Autotrophic organisms convert other forms of energy into chemical energy:

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14
Q

Name some chemoautotrophic organisms.
What energy do they use?

A
  1. Some bacteria
  2. Archaea

They use the energy derived from oxidation of electron donors e.g. H2, Fe2+, H2S.

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15
Q

Name some photoautotrophic organisms.
What energy do they use?

A
  1. Green plants

They use light energy in photosynthesis.

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16
Q

Name some heterotrophic organisms.
What energy do they use?

A

Animals

They derive their chemical energy from food.

17
Q

Where do organisms store chemical energy?

A

Organisms store chemical energy mainly in lipids and carbohydrates.

18
Q

What molecule makes energy available?

A

The molecule that makes the energy available when it is needed is adenosine triphosphate, ATP.

19
Q

How much ATP do we make and break down everyday?
How much ATP does the body contain?
What can you conclude from this?

A

We make and break down about 50 kg ATP every day.

The body only contains about 5 g ATP.

Hence ATP is is not an energy store.

20
Q

What is ATP otherwise called as?
Why?

A

It is sometimes called the ‘energy currency of the cell.

It is so called because it is involved when energy changes happen.

21
Q

When is ATP synthesised?
When is ATP broken down?

A

ATP is synthesised when energy is made available, such as in the mitochondria.

It is broken down when energy is needed, such as in muscle contraction.

22
Q

Nucleotide (Key-Term)

A

Monomer of nucleic acid comprising a pentose sugar, a nitrogenous base and a phosphate group.

23
Q

Pyrimidine bases (Key-Term)

A

Class of nitrogenous bases including thymine, cytosine and uracil.

24
Q

Purine bases (Key-Term)

A

Class of nitrogenous bases including adenine and guanine.

25
Q

What do you need to remember about the spelling of nucleotides?

A

Take care with spelling: ‘pyrimidine’ not ‘pyramidine’; ‘thymine’ not ‘thiamine”.

Cytosine and thymine contain the letter ‘Y’; so does pyrimidine.

26
Q

Chemoautotrophic (Key-Term)

A

An organism that uses chemical energy to make complex organic molecules.

27
Q

Photoautotrophic (Key-Term)

A

An organism that uses light energy to make complex organic molecules, its food.

28
Q

(ATP) Adenosine triphosphate (Key-Term)

A

A nucleotide in all living cells.
Its hydrolysis makes energy available.
It is formed when chemical reactions release energy.

29
Q

What do we know about the estimates for the mass of ATP stored and metabolised by the body?

A

Estimates for the mass of ATP stored and metabolised by the body vary greatly.

30
Q

Draw a diagram of:

  1. Structure of a nucleotide
  2. Purine skeleton
  3. Pyrimidine skeleton
A

WJEC Biology AS Level - Marianne Izen - 2nd Edition (74 decks)

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