Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > 2. Nucleic Acids > Flashcards

2. Nucleic Acids Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Give 2 examples of nucleic acids

A 
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Give the 3 components that make up a nucleotide

A
  • A pentose sugar (deoxyribose/ribose sugar)
  • A phosphate group
  • A nitrogen containing base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 nitrogen containing bases found in DNA?

A

Adenine
Thymine
Guanine
Cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 4 nitrogen containing bases found in RNA?

A

Adenine
Uracil
Guanine
Cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are mononucleotides formed?

A

The pentose sugar, phosphate group and organic base are joined by a condensation reaction, forming a mononucleotide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are dinucleotides formed?

A

A result of a condensation reaction between the deoxyribose sugar of one mononucleotide and the phosphate group of another. The 2 nucleotides form a phosphodiester bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What links the two strands of DNA together?

A

Hydrogen bonds link the two complementary nucleotide base pairs together. Adenine pairs with thymine, cytosine with guanine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the name of the coil of DNA that forms its backbone?

A

Double helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is DNA a stable molecule?

A
  • The phosphodiester backbone protects the more chemically reactive organic bases inside the double helix.
  • Hydrogen bonds link the organic base pairs forming bridges between the phosphodiester uprights. As there are 3 hydrogen bonds between cytosine and guanine, the higher proportion of C-G pairings, the more stable the DNA molecule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of DNA?

A
  • Hereditary material that is responsible for passing genetic material from cell to cell and down generations.
  • A total of approx. 3.2 billion base pairs in the DNA of a typical mammalian cell. Therefore almost an infinite variety of base sequences, providing genetic diversity in living organsims.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is DNA adapted to carry out its functions?

A
  • It’s a very stable structure which normally passes from generation to generation without change.
  • Its two separate strands are joined only by hydrogen bonds, allowing them to separate during DNA replication and protein synthesis.
  • Its an extremely large molecule and therefore carries a large amount of genetic information.
  • By having the base pairs within the helical cylinder of the deoxyribose-phosphate backbone, the genetic information is to some extent protected from being corrupted by outside chemical and physical forces.
  • Base pairing leads to DNA being able to replicate and transfer information as mRNA.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the function of DNA rely on?

A

The sequence of DNA base pairs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Suggest why base pairing of cytosine with adenine and guanine with thymine doesn’t occur?

A

The base pairs are linked by hydrogen bonds. The molecular structures could be such that hydrogen bonds don’t form between adenine and cytosine and between guanine and thymine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If the base sequence on one strand of DNA is TGGAGACT, determine the sequence of the other strand.

A

ACCTCTGA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

If 19.9% of base pairs on human DNA is guanine, calculate the percentage of thymine

A

19.9% guanine so 19.9% cytosine
Total C-G is 39.8%
So total A-T is 60.2%
so thymine must be 30.1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give the 2 main stages of cell division

A
  • Nuclear division

- Cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 4 requirements needed for semi-conservative replication to occur?

A
  • The 4 types of nucleotide, with their bases present.
  • Both strands of DNA act as a template for the attachment of these nucleotides.
  • The enzyme DNA polymerase.
  • A source of chemical energy.
18
Q

Describe the process of semi-conservative replication.

A

The enzyme DNA helicase breaks the hydrogen bonds linking the base pairs of DNA.
As a result, the double helix separates itself into 2 strands and unwinds.
Each exposed polynucleotide strand then acts as a template to which complimentary free nucleotides bind by specific base pairing.
Nucleotides are joined together in a condensation reaction by the enzyme DNA polymerase to form the missing polynucleotide strand on each of the 2 original polynucleotide strands of DNA.

19
Q

Explain why the process of DNA replication is described as ‘semi conservative’

A

Because half of the original DNA is built into the new DNA strand.

20
Q

If an inhibitor of DNA polymerase were introduced to a cell, explain the effect on DNA replication.

A

The linking together of new nucleotides could not take place. While the nucleotides would match up to their complementary nucleotides on the original DNA strand, they wouldn’t join together to form a new strand.

21
Q

What type of molecule is ATP?

A

A phosphorylated macromolecule

22
Q

What are the 3 parts of ATP?

A
  • Adenine: a nitrogen-containing organic base.
  • Ribose: a pentose sugar, acting as the backbone of the molecule.
  • Phosphates: a chain of 3 phosphate groups.
23
Q

How does ATP store energy

A

The bonds between the phosphate groups are unstable and so have a low activation energy, which means they’re easily broken. When they break they release a considerable amount of energy.

24
Q

State the equation for the conversion of ATP into energy.

A

ATP + (H2O) -> ADP + Pi (inorganic phosphate) + Energy

25
Q

What type of reaction converts ATP to energy?

A

Hydrolysis- water is used to convert ATP to ADP.

26
Q

Name the enzyme that catalyses the reaction converting ATP into energy

A

ATP hydrolase

27
Q

What is the type of reaction which synthesises ATP from ADP.

A

Condensation- water is removed.

28
Q

Name three ways ATP is synthesised from ADP

A
  • In chlorophyll-containing plant cells during photosynthesis.
  • In plant and animal cells during respiration.
  • In plant and animal cells where phosphate groups are transferred from donor molecules to ADP
29
Q

Why is ATP an unsuitable long term energy store?

A

Due to the instability of its phosphate bonds. Fats and carbohydrates are better stores.

30
Q

Why is ATP a better immediate energy source than glucose?

A
  • Each ATP molecule releases less energy than each glucose molecule. The energy for reactions is released in smaller, more manageable quantities.
  • The hydrolysis of ATP to ADP is a single reaction that releases immediate energy. The breakdown of glucose is a long series of reactions and therefore energy re,ease takes longer.
31
Q

What processes require ATP in cells?

A
  • Metabolic processes
  • Movement
  • Active transport
  • Secretion
  • Activation of molecules
32
Q

Explain why ATP is referred to as an ‘immediate energy source’

A

ATP releases its energy very rapidly. This energy is released in a single step and transferred directly to the reaction requiring it. It’s too unstable to be a long term store.

33
Q

Explain how ATP can make an enzyme-catalysed reaction take place more readily.

A

ATP provides a phosphate that can attach to another molecule, making it more reactive and so lowering its activation energy. As enzymes work by lowering activation energy they have less work to do and function more readily.

34
Q

Explain why water is described as a ‘dipolar’ molecule

A

The oxygen atom has a slight negative charge, while the hydrogen atoms have a slight positive one.

35
Q

Explain how water molecules form hydrogen bonds.

A

The positive pole of one water molecule will be attracted to the negative pole of another. The attractive force between these molecules is called a hydrogen bond.

36
Q

Why is the boiling point of water higher than expected?

A

Because water molecules stick together, it takes more energy to separate them.

37
Q

What are the advantages of water having a high specific heat capacity?

A

Water acts as a buffer against sudden temperature variations, making the aquatic environment temperature-stable. As organisms are mostly, water, it also buffers them against sudden temperature changes especially in terrestrial environments.

38
Q

Describe cohesion and give an example

A

Cohesion is the tendency of molecules to stick together. With its hydrogen bonding, water has large cohesive forces and these allow it to be pulled up a tube, such as xylem vessel in plants.

39
Q

Describe surface tension and give an example

A

Where water molecules meet the air they tend to be pulled back into the body of water rather than escaping from it. This surface tension allows water to be strong enough to support small organisms such as pond skaters.

40
Q

What is the importance of water in metabolism?

A
  • Water is used to break down complex molecules by hydrolysis and is produced in condensation reactions.
  • Chemical reactions take place in an aqueous medium.
  • Water is a major raw material in photosynthesis.
41
Q

As a solvent, name substances that water can readily dissolve

A
  • Gases- oxygen, carbon dioxide
  • Wastes- ammonia, urea
  • Inorganic ions, small hydrophilic molecules
  • Enzymes, whose reactions take place in a solution.

Biology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions