Brainscape's Knowledge GenomeTM

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


See full index

Biological Systems > Chapter 3 Nucleic Acids, Proteins and Enzymes > Flashcards

Chapter 3 Nucleic Acids, Proteins and Enzymes Flashcards

1
Q

What are nucleic acids, and what are the two types?

A

Polymers that store, transport and express hereditary information (genes)
Two types are DNA and RNA

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

What are nucleotides and what are its components?

A 
Monomer of nucleic acids.
Components
- Pentose Sugar (either ribose or deoxyribose)
- Phosphate Group
- Nitrogen containing base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the difference between a nucleoside and a nucleotide?

A 
Nucleoside = Nitrogen containing base + pentose sugar (no phosphate group)
Nucleotide = nucleoside + phosphate group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two types of bases?

A

Prymidines (single ring)

Purines (double rings)

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

How do new nucleotides bond to nucleic acids?

A

One at a time. Pentose sugar bonds to phosphate on next nucelotide
Bonds at #5 carbon on one nucleotide to #3 carbon on next (5 –> 3 direction)

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

Define Oligonucleotides

A

Up to 20 nucleotides

e.g. small RNA molecules that regulate DNA replication and gene expression

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

What is an example of a polynucleotide?

A

DNA and RNA (longest polynucleotides in living world)

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

How are base pairs bonded and what makes them strong?

A

Bond via hydrogen bonds. Stronger due to number of hydrogen bonds (not as strong as covalent bonds)

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

What kind of helix is DNA?

A

Right handed helix (goes direction of fingers of a right hand if made into a fist with thumb pointing up)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two primary functions of DNA?

A

Replication

Transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe transcription and translation

A

Transcription: Information from DNA is copied onto RNA
Translation: information then used to specify amino acid sequences in proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the major functions of Proteins?

A

Enzymes: catalyzing molecules
Defensive proteins: e.g. antibodies
Hormonal and regulatory proteins: e.g. insulin
Receptor Proteins: receive and respond to intra and extracellular signals
Storage proteins: Store amino acids for later use
Transport proteins: e.g. haemoglobin
Genetic respiratory proteins: regulate gene expression

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

What are the 2 components of amino acids?

A

Nitrogen containing amino group
Acidic carboxyl group
Distinct R group

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

What are the 3 special case amino acids?

A

Glycine - single H atom. able to fit in interior of protein molecules
Proline - ring structure. Limits H bonding and rotation. Stabilises bends or loops in protein.
Cysteine - can form covalent bonds called ‘disulfide bridges’ which affect how a protein molecule folds

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

Difference between an oligopeptide and a polypeptide.

A

Oligopeptide - 20 or fewer amino acids

Polypeptide - larger polymer. Functional proteins contain one or > polypeptides.

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

What is the range in number of amino acids in proteins?

A

51 (insulin) to 34,350 (titin) amino acids

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

How is the process of amino acids being added to an existing polypeptide similar to nucleotides being added to a nucleic acid chain?

A

Added one at time in a condensation reaction.

In the case of polypeptides it forms a peptide bond and goes in the direction of amino to carboxyl.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the primary stucture of a protein?

A

amino acid sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the secondary structure of a protein?

A

regular, repeate spatial patterns in different regions resulting from Hydrogen bonding
alpha helix - right hand coil
beta pleated sheet - 2 or more sequences extended and aligned

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the tertiary structure of a protein?

A

bonds that form between polypeptide chains - resulting in definitive 3D shape
- Determined by R group interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Explain the 4 R group interactions that determine tertiary structure of a protein

A
  • Disulfide bridges hold folded polypeptides together
  • H bonds stabilize folds
  • hydrophobic side chains aggregate in interior
  • Van der Waals interactions between hydrophobic side chains
  • ionic interactions form salt bridges (deep in the protein)
22
Q

Define denaturing

A

Disruption of secondary and tertiary structures of a protein by heat or chemicals.
- Will normally return to normal when cooled or chemical removed

23
Q

What is the quarternary structure of a protein?

A

2 or more peptide chains (subunits) bonding together by hydrophobic and ionic interactiosn and H bonds
- Unique tertiary structure

24
Q

What are teh factors that cause denaturing?

A

Temperature
Change in concentration of H+ (pH)
High concentration of polar substances
Non-polar substances (in parts of protein where hydrophobic groups maintain structure)

25
How do proteins interact with other molecules?
R groups on surface may form weak interactions with groups on surface of another molecule. - can change tertiary structure of protein Or chemical group can covalently bond to side chain of 1 or more of its amino acids
26
What is the function of catalysts in living systems
Living systems depend on reactions that occur spontaneously at slow rates. Catalysts speed up the reactions without being permanently altered (DO NOT make reactions that would not occur otherwise)
27
What are biological catalysts
Proteins (enzymes) and a few RNA molecules (ribosomes)
28
What is free energy (G) and how is it released
The amount of energy in a system that is able to do work. | Released by exergonic reactions
29
What is activation energy?
The input of energy that initiates a reaction by putting reactants into transition state. Can come from heat (molecules have increased kinetic energy)
30
Why is it not possible for heat to be used to speed up reactions by creating activation energy in living systems
Because it speeds up all reactions, including destructive ones
31
How do enzymes act on activation energy?
Lower threshold of activation energy by enabling reactants to come together and react more easily
32
What allows enzymes to be very specific
Individual 3D shape of active site
33
What is the name of the bond between enzymes and reactants and how is it held together?
Enzyme-substrate complex. Held together by H bonding, ionic attraction or temporary covalent bonding
34
How do enzymes catalyze a reaction?
- Inducing strain: bonds in substrate are stretched (causing transition state) - Substrate orientation: substrates are brought together so bonds can form - Adding chemical groups: R group may be directly involved
35
Define induced fit
enzyme changes shape when substrate bonds to make the binding tight
36
What are cofactors?
Other molecules that help proteins function - metal ions: participate in enzyme catalyzed reaction - Coenzymes: add or remove chemical group from substrate. NON-Specific - Prosthetic group: molecules permanently bound to their enzyme
37
What factors affect the rate of catalyzed and uncatalyzed reactions
Uncatalyzed directly proportional to concentration of substrate Catalyzed - concentration of enzymes (rate levels out as enzymes become saturated)
38
What are metabolic pathways?
Multiple enzyme catalyzed pathways where the product of one reaction is the substrate for the next and each step is catalyzed by a specific enzyme
39
What is systems biology?
A new field that describes the components of metabolic pathways mathematically
40
How do cells regulate metabolism
Controlling amount of an enzyme (turning synthesis on or off) OR Regulating enzyme ACTIVITY (faster option)
41
How is enzyme activity regulated?
Chemical inhibitors bind to enzyme and slow rates through reversible and irreversible inhibition.
42
What are the functions of natural and artificial inhibitors
- Natural inhibitors regulate metabolism | - Artificial inhibitors are used to treat diseases, kill pests and study enzyme function
43
Explain the process of irreversible inhibition
Inhibitor covalently bonds to side chain in active side permanently deactivating enzyme
44
What are the two types of reversible enzyme inhibors
Non-competetive:similar shape to enzyme substrate binds at site distinct form active site causing change in enzyme shape and function (slows or prevents bonding) Competetive: binds at active site but no reaction occurs (competes with substrate)
45
What is allosteric regulation
Non-substrate molecule binding to a site other than the active site (allosteric site) - Enzyme chagnes shape and alters affinity of active site for substrate - can activate or deactivate enzymes
46
What types of bonds can modify allosteric sites
covalent or non-covalent (both are reversible)
47
Explain the process of Phosphorylation
By the protein kinase. - can change hydrophobic regions to hydrophilic, causing enzymes to twist and expose active sites - Protein phosphatases reverse the process by removing a phosphate group
48
What are key steps in metabolic pathways
Commitment step - first reaction | Feedback inhibition - final product acts as inhibitor for first enzyme
49
What are 2 factors that change protein shape in living systems
pH and temperature
50
What is the law of mass attraction?
Higher H+ concentration, the more the reaction is driven to the left (less hydrophilic form)
51
How does temperature affect protein shape
temperature increases rate of chemical reactions. If temperature is too high, noncovaelent bonds can break and inactivate proteins (denature)
52
What are isozomes
enzymes that catalyze the same reaction but have different composition and physical properties - May have different optimal pH or temperature allowing an organism to adapt to its environment

Biological Systems (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions