Brainscape's Knowledge GenomeTM

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


See full index

Principles > Biochemistry > Flashcards

Biochemistry Flashcards

1
Q

What are the major classifications of carbohydrates?

A

Monosaccharides (one carbohydrate group), disaccharides (two carbohydrate groups), polysaccharides (many carbohydrate groups)

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

What are the first and second laws of thermodynamics ?

A 
First = energy is neither created or destroyed just converted from one form to another 
Second = when energy is converted from one form to another, some of the energy becomes unavailable to work.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is entropy?

A

A measure of the amount of disorder in a system

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

Describe free energy

A

= energy of of products - energy of reactants
Reactions in which the free energy change is negative can occur spontaneously (exergonic)
Reactions in which the free energy change is positive cannot happen spontaneously and so an input of energy is needed to proceed. (Endergonic)
The closer delta G is to zero the more likely the reaction is reversible

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

Which is less stable of ATP and ADP?

A

The negative charges close together in ATP put a strain on the molecule and make it less stable than ADP. The strain is relieved partially by removing one or more phosphate groups. (Anhydride bonds are high energy)

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

What is catabolism?

A

Breaking down complex molecules into smaller ones and releasing energy

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

What is anabolism ?

A

Synthesising complex molecules out of smaller ones in energy consuming reactions

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

What is a nucleoside ?

A

Base + sugar

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

What is a nucleotide ?

A

Base + sugar + phosphate group(s)

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

What are the differences between DNA and RNA?

A

DNA
-ATGC, 2-deoxyribose sugar, double stranded, building blocks = dATP, dCTP, dGTP, dTTP

RNA
-AUGC, ribose sugar, single stranded, building blocks = ATP, CTP, GTP, UTP

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

What are the names of the bases when they are converted to nucleosides?

A

Adenosine, cytidine, guanosine, thymidine, uridine

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

Describe polymerisation.

A

Nucleotides with 3 phosphates attached are added to the 3’ end when the -OH group is. The pyrophosphate ion (2 phosphates) is released and the bond is broken releasing energy to drive the action.

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

Which end of the DNA strand are new nucleotides are added to?

A

The 3’ end

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

Describe the structure of DNA

A

Double helix, four bases ATGC, two antiparallel strands (5’ to 3’ and 3’ to 5’), sugar-phosphate backbone on the outside and base pairs of the inside.
A joins to T with two hydrogen bonds and G joins to C with three hydrogen bonds

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

What is DNA replication?

A

Replicating DNA before cell division so that daughter cells have a complete complement of the genome.
It is semi-conservative (half of the original strand is not used during replication)
It is catalysed by DNA polymerase but cannot start DNA synthesis on their own (requires RNA primer)

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

Describe eukaryotic DNAs origins of replication?

A

Eukaryotic genomes have many origins of replication and it can start simultaneously at several pony’s in the genome (bidirectional, ensures replication is reasonably quick)

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

What happens during DNA replication on the leading and lagging strand.

A

Leading strand is continuous 3’ to 5’

Lagging strand is in segments (Okazaki fragments) 5’ to 3’

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

What unwinds the DNA before replication?

A

Helicase

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

How can DNA be proofread/ repaired ?

A

DNA polymerase has 3’ to 5’ exonuclease activity which removed incorrect nucleotides and improves the error rate.

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

Describe RNA

A
  • Single stranded, has U instead of T
  • can contain stretches of intramolecular base pairing (stem loops)
  • rRNA combines with proteins to form ribosomes
  • tRNA carries amino acids to make proteins
  • mRNA carries genetic info for protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe tRNA

A

Have anticodon consisting of three nucleotides . Specific amino acids are attached to the 3’ end.
All tRNA molecules have a 3D structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe RNA polymerase

A
  • makes RNA
  • eukaryotic cells have three types Pol 1, Pol 2, Pol 3
  • Pol 2 synthesises all mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How can unfavourable cellular processes take place?

A

By coupling them with a highly favourable process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the types of amino acid?

A
  • non polar/hydrophobic
  • polar / uncharged
  • acidic
  • basic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are polypeptides made up of?

A

20 different L amino acids. D and L refers to the stereochemistry of the amino acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which direction are polypeptides synthesised?

A

From the n terminus to the c terminus

They have partial double bond character due to electrons from the n and c terminus contributing to the bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is pH?

A

A measure of the amount of protons in a solution

28
Q

What is cationic and anionic ?

A 
Cationic = positive amino acid
Anionic = negative amino acid
29
Q

What are zwitterons?

A

Amino acids without charged side groups in neutral solutions.

30
Q

What is the isoelectric point?

A

The pH at which a molecule has no net charge.

31
Q

How can polypeptides rotate?

A

Amino acids are planar but polypeptides can rotate around angle between the alpha carbon and the amino group/ carboxyl groups

32
Q

Describe secondary structure of poly peptides.

A

-stabilised by H bonding

Three types - alpha helixes, beta sheets and turns, and collagen triple helixes

33
Q

Describe alpha helixes

A

One rod-like polypeptide chain

Mostly right handed , co group forms hydrogen bonds with NH group 4 residues away.

34
Q

Describe beta sheets and turns

A

Polypeptide backbone almost entirely extended.
Hydrogen bonds between neighbouring groups
Can involve parallel and antiparallel chains + turns
Repeating zigzag structure

35
Q

Describe the collagen triple helix

A

Composed of bone and connective tissues
Has water insoluble fibres
Three left handed helical chains twisted around each other
Repeated sequence X-Y-gly in all strands

36
Q

what are fibrous proteins ?

A

polypeptide chains organised approximately parallel along a single axis (long, mechanically strong, insoluble in water, fibres)

37
Q

what are globular proteins?

A

proteins folded into a spherical shape (soluble in water, polar side chains, non-polar inside)

38
Q

what are the forces stabilising tertiary structures?

A

covalent disulphide bonds, salt bridges, hydrophobic interactions, hydrogen bonds, complex formations with metal ions

39
Q

what can disrupt protein structures?

A

heat, extreme pH, detergents, urea, reducing agents

40
Q

what is the central dogma?

A

the process of DNA>RNA>proteins

41
Q

where does DNA replication, transcription and splicing occur?

A

nucleus

42
Q

where does translation occur?

A

ribosome

43
Q

what are nucleotides and nucleosides?

A 
nucleotides = base, sugar and phosphate
nucleosides = base and sugar
44
Q

what happens in DNA polymerisation?

A

nucleotides with 3 phosphates attached are added to the 3’ end of the DNA strand and attached to the -OH group. the pyrophosphate ion is released and the bond is broken releasing energy.

45
Q

what does it mean that DNA replication is semi-conservative?

A

This means that the two parental strands separate and each makes a new copy of itself. it is catalysed by DNA polymerase. It requires an RNA primer to start.

46
Q

what do the names of bases become when its in nucleosides?

A 
adenosine
cytidine 
guanosine
thymidine
uridine
47
Q

what are the DNA and RNA building blocks?

A

dATP, dTTP. dGTP, dCTP

ATP, TTP, GTP, CTP

48
Q

Describe RNA / RNA polymerases

A

made up of RNA polymerases which is a multi-subunit complex
eukaryotic cells have 3 types of RNA polymerase pol 1, pol 2 and pol 3.
pol 2 is used in the synthesis of all mRNA

49
Q

what do TATA boxes?

A

The TATA box is present about 25 nucleotides before the initiation site. The TATA box binding protein (TBP) is part of the TF2D general transcription factor which recognises the TATA box and introduces a kink in the DNA to determine start and direction. it also provides a landing platform for other transcription factors and RNA polymerase.

50
Q

what do promoters do?

A

RNA polymerases bind promoters which initiates transcription. The promoter is not a protein it is a DNA sequence marking the start of a gene.

51
Q

what is transcription elongation/ what happened?

A

A transcription bubble moves in one direction aiding the DNA, the DNA is unwound in front of the polymerase and rewound behind it.

52
Q

what happens in termination of transcription?

A

newly synthesised RNA makes a stem loop structure followed by a stretch of U’s and a specific enzyme cleaves the RNA

53
Q

what do transcription factors do?

A

transcription requires specific transcription factors to bind to DNA. these contain two functional domains (DNA binding domain and transcriptional activation domain). They regulate transcription positively or negatively.

54
Q

how are the ends of mRNA transcripts processed?

A

GTP ‘cap’ added to the 5’

poly A tail added to 3’ end

55
Q

what does DNA being degenerative mean?

A

amino acids can have more than on codon

56
Q

what does DNA being unambiguous mean?

A

each codon codes for only one amino acid

57
Q

what does DNA being nearly universal mean?

A

all organisms DNA is mostly the same

58
Q

what do aminoacyl-tRNA synthetases do?

A

bind amino acids to their corresponding tRNA molecules. uses ATP.

59
Q

describe ribosomes

A

they contain four rRNA molecules. they have three tRNA binding sites. E=exit, P=peptidyl, A=aminoactyl

60
Q

describe initiation

A

requires initiation factors
GTP is hydrolysed for energy
ribosome binds to the 5’ end of mRNA
moves along mRNA until START codon is found
special ‘initiator’ tRNA base pairs with the START codon
The polypeptide is assembled and initiator tRNA is now located in P site

61
Q

what are cholesterols functions in health?

A
  • maintains fluidity and structure in plasma membrane
  • forms lipid ‘rafts’ that form bridges between receptor proteins and second messengers.
  • precursor molecules for bile/ bile acids, vitamin D and steroid hormones.
62
Q

what is triglycerides functions in health?

A

-highly concentrated in energy stores.

63
Q

how are lipids carried around the body?

A
  • they require specialised proteins to carry them called lipoproteins.
64
Q

what are the different types of lipoproteins?

A
  • VLDL (very low density lipoproteins)
  • IDL (intermediate)
  • LDL (low density)
  • HDL (high density - carries cholesterol back from tissues to liver)
65
Q

what role does cholesterol play in atherosclerosis?

A

cholesterol is transported away from the tissues (VLDL, IDL, LDL) and towards them (HDL). the two exist in balance and if transport away from tissues is more then cholesterol accumulates in vessels leading to atherosclerosis.

66
Q

What happens in the blood vessels in atherosclerosis?

A

inflammation > increased endothelial permeability > fatty streaks form (initially leukocytes and lipid, then later smooth muscle) >progresses to intermediate and advanced lesions > forms fibrous cap that walls off lesion from lumen > rupture or ulceration of fibrous plaque leads to thrombosis.

67
Q

what do statins do?

A
  • lower cholesterol and reduce risk of atherosclerosis

- much more

Principles (15 decks)

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