Nucleic acids

What are nucleotides made of?

Pentose sugar

Nitrogenous base

Phosphate group

Name the components of this nucleotide

EQ

Guanine

Deoxyribose

Phosphate group

Identify 2 differences between a DNA nucleotide and a molecule of ATP

EQ

Both have adenine

Both have at least 1 phosphate group

How many phosphates does ATP have?

EQ

3

Explain how the pairing of nitrogenous bases allows identical copies of of DNA to be made

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A bind to T

G binds to C

By hydrogen bonding

Purling can only bind with pyrimidine as they are different sizes

Draw a phosphodiester bond between 2 molecules

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What base is present in ATP

EQ

Adenine

Explain why the mass of ATP in the body decreases near the end of the day

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ATP broken down to provide energy for metabolic reactions

Similarities between DNA replication and Transcription

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DNA unwinds And unzips by helicase

Template DNA in both

H bonds

Free nucleotides

Polymerase enzymes

Differences between DNA replication and transcription

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Small section of DNA unzips in transcription but both strands act as templates during replication

RNA in replication DNA in transcription

RNA polymerase in replication DNA polymerase in transcription

Different helicase enzymes

What does DNA replication form

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2 new daughter strands

That remain bound to the template strand

What does transcription produce

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1 mRNA strand that leaves the nucleus

State 2 enzymes involved in DNA replication

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DNA polymerase

Helicase

Explain the meaning of the phrase semi conservative replication

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DNA contains 1 original strand and one new strand

Function of DNA polymerase

EQ

Forms phosphodiester bonds

What is shown here

EQ

Shows how DNA contains nitrogen 14 and Nitrogen 15

What is shown here

EQ

The highest band gets thicker because More DNA made from nitrogen 14

Outline how the process of DNA replication is completed

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DNA polymerase

Condensation reaction between phosphate and sugar

DNA winds into double helix

Explain why a process know as transcription is necessary for polypeptide synthesis

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DNA is too large to leave teh nucleus

So the gene is copied to mRNA

Explain how the genetic code in the gene for tubulin codes for the protein tubulin

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Every 3 bases code for an amino acid

Non overlapping

Suggest 2 ways tubulin is essential to protein synthesis and protein secretion in eukaryotic cells

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Movement of vesicles from rer to Golgi

Movement of mRNA from nucleus to ribosome

Why can’t pineapple juice be used as a substitute to protease enzyme?

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It contains DNA

Do you always have to use a water bath in a dna extraction process

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No

What does the salt do in dna extraction process?

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Helps DNA precipitate

What type of membrane does detergent break?

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ALWAYS say plasma membrane

A dna molecule contains 2 polynucleotide chains

Describe how theses 2 chains are held together

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Phosphodiester bonds in backbone

Hydrogen bonding

Purine bonds to pyrimidine

Explain how the nucleotides in a dna molecule are arranged as 2 polynucleotide strands

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Nucleotide adjoined by phosphodiester bonds

Hydrogen bonds between complementary bases

Antiparallel

D

Are ribosomes membrane bound?

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No

Are mitochondria membrane bound?

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Yes

Are lysosomes membrane bound?

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Yes

Do purine bases always pair with pyrimidine bases?

EQ

Yes

A

What bond is present between 2 nitrogenous bases holding 2 polynucleotide chains together

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Hydrogen

Do phosphodiester bonds break and reform during DNA replication?

EQ

No

Do hydrogen bonds break and reform during DNA replication?

Yes

Function of DNA polymerase

EQ

Make phosphodiester bonds between adjacent nucleotides

Evidence that DNA replication is semiconsservative

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After one replication number of Adenine nucleotides is equal to the number of guanine nucleotides

After 2 replications two DNA molecules have one original and one new strand and 2 DNA molecules have 2 new strands

In what direction can DNA polymerase work?

EQ

From the 3’ end to the 5’ end

Means that the lagging strand has small gaps left in the backbone

DNA polymerase can only work From the 3’ end to the 5’ end

What does this mean for the lagging strand?

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Small gaps left in the backbone

What seals the gaps in the lagging strand?

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DNA ligase

Non-overlapping definition

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Each nucleotide is only part of one triplet of bases

Degenerate definition

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More than 1 triplet codes for a specific amino acid

How many nitrogen carbon rings does purine have?

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2

Are lipids polymers?

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No

What are lipids?

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PolysaccharidEs

Are nucleic acids polymers?

EQ

Yes

Are proteins polymers?

EQ

Yes

What parts of a molecule bond to phosphate when phosphodiester bonds are formed?

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OH

OH

Describe how a polynucleotide is formed from its monomers

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Nucleotides joined by phosphodiester bonds in a condensation reaction

Describe the action of helicase

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Unzips double helix

Breaks hydrogen bonds between 2 strands

Explain how errors may occur during DNA replication

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Mutation

Change in DNA base sequence

What does salt do in DNA extraction process

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Breaks hydrogen bonds between dna and water

What does ethanol do in DNA extraction process?

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Precipitate out dna

What does the detergent do in DNA extraction investigation?

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Breaks down the plasma membrane

Why is ice cold ethanol used during the DNA extraction process

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Reduces enzyme activity

What forms phosphodiester bonds?

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Deoxyribose

Phosphate

Is ADP a nucleotide?

EQ

Yes

State the role of DNA polymerase

EQ

Catalyses the formation of phosphodiester bonds

Suggest how a mutation in the cytoskeleton genes could cause a disease of the nervous system

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Change in structure of protein

Affects speed of nerve impulses

What enzyme hydrolyses DNA

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Protease

Outline the role of RNA polymerase in the production fo mRNA sequence

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Joins nucleotides

Forms phosphodiester bonds

Suggest why modified proteins last longer

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Change in primary structure means change in tertiary structure

No longer complementary to enzymes

Transcription + translation

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From gene to when polypeptide is made

Transcription produces mRNA

mRNA leaves nucleus

Translation at ribosomes

tRNA with specific amino acids binds to its anticodon

What enzyme joins nucleotides together

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RNA polymerase

What is a ribosome made of

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RRNA

Protein

What brings the specific amino acids to be joined at the polypeptide?

EQ

TRNA

What elements do nucleotides contain elements?

H

O

N

P

C

What type of acid are DNA and RNA?

Nucleic acids

What is DNA used for?

Store genetic information

Function of RNA

Make proteins from instructions in DNA

What type of sugar does DNA contain?

Deoxyribose a type of pentose sugar

What are ADP and ATP used for?

To store and transport energy in cells

Does each DNA nucleotide have the same phosphate group

Yes

Name the 4 bases

Cytosine.

Guanine

Thymine

Adenine

How many polynucleotide chains does DNA contain?

2

What sugar is in nucleotides in RNA

Ribose sugar

In RNA …… replaces thymine

Uracil

How many polynucleotide chains does RNA contain

One

What type of bases are adenine and guanine

Purines

What type of bases are cytosine uracil thymine?

Pyrimidine

What does a purine base contain?

2 carbon nitrogen rings

What does a pyrimidine base contain?

One carbon nitrogen ring

Which is smaller

A pyrimidine base or purine base

Pyrimidine base

What type of nucleotides are ADP or ATP

Phosphorylated Nucleotides

How do you phosphorylate a nucleotide

Add one or more phosphate groups

What bases does ADP contain?

Adenine

Ribose sugar

2 phosphate group

What does ATP contain?

Adenine

Ribose sugar

3 phosphate groups

Why is ATP used instead of the pure energy?

Cells can’t get its energy directly from glucose

What is ATP used for

Provide energy for chemical reactions

What is ATP synthesised from

ADP and inorganic phosphate

How is ATP made from ADP

ADP is phosphorylated to form ATP

So phosphate bond is formed

How is energy used from a cell

ATP broken down to ADP and inorganic phosphate

Energy released from phosphate bond

What do nucleotides join together to form

Polynucleotides

How do nucleotides join together

Join by phosphate group of one nucleotide and sugar of another via condensation reaction

Form phosphodiester bond

How can phosphodiester bonds be broken

Hydrolysis

What shape do polynucleotide strands join to form

Anti-parallel strands

Double helix

How do the strands join together

Hydrogen