Brainscape's Knowledge GenomeTM

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


See full index

bio module 2 > nucleic acids > Flashcards

nucleic acids Flashcards

1
Q

features of nucleotides

A
  • repeating monomers forming nucleic acids
  • large, contained in nucleus of cells
  • important in the storage and transfer of genetic info to make proteins
  • form polynucleotides by forming phosphodiester bonds
  • become phosphorylated nucleotides when they contain more than one phosphate group
  • help regulate many metabolic pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

nucleotide structure

A

phosphate group, 5C (pentose) sugar (deoxyribose/ribose), nitrogenous base

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

how are polynucleotides formed

A
  • condensation reactions between nucleotides form strong phosphodiester bonds
  • phosphodiester bonds form between the phosphate group of one nucleotide and the C3 on the next
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how are polynucleotides broken down

A

-hydrolysis reactions use a molecule of water to break the phosphodiester bonds between nucleotides

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

where is dna found in eukaryotes

A
  • nuclei of cells
  • each large DNA molecule is wound around histone proteins into chromosomes
  • there’s a loop of dna (without histones) inside mitochondria and chloroplasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where is dna found in prokaryotes

A
  • in a loop in the cytoplasm, not enclosed in a nucleus
  • not wound around histones (described as naked)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

dna features

A
  • large, stable
  • double stranded molecule
  • hereditary material
  • carries coded instructions used in the development and functioning of all living organisms
  • contains genes that code for proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the purine bases and their features

A
  • adenine and guanine
  • large
  • two ring structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the pyrimidine bases and their features

A
  • thymine, cytosine, uracil
  • smaller
  • one ring structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

phosphate group features

A
  • inorganic molecule (not made of C atoms)
  • negatively charged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

dna structure

A
  • polymer
  • made of many monomeric units, nucleotides
  • strands are antiparallel
  • large
  • covalent phosphodiester bonds between nucleotides form
    —> broken when polynucleotides break down
    —> formed when polynucleotides are synthesised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

antiparallel meaning

A
  • the two dna strands run in opposite directions
    —> refers to the direction C3 and C5 on deoxyribose are facing
  • 5’ end - where phosphate group is attached to C5 on deoxyribose
  • 3’ end - where phosphate group is attached to C3 on deoxyribose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

hydrogen bonds

A
  • antiparallel strands are joined to eachother by H bonds between bases
  • A and T: 2 H bonds
  • (RNA) A and U: 2 H bonds
  • G and C: 3 H bonds
  • H bonds allow molecule to unzip for transcription and replication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why do purines always pair with pyrimidines

A
  • gives equal sized rungs on the dna ladder
    —> these can then twist into the double helix
    ——> gives molecule stability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the genome

A

the genome of every cell in an organism carries the coded instructions to make and maintain that organism

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

what are the reasons for dna replication

A
  • cell division - new cells need new DNA for growth and repair, also so each new daughter cell recieves the full set of instructions
  • reproduction - gametes require dna to pass on genetic info
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does semi conservative replication mean

A
  • each of the 2 identical dna molecules produced contain one old strand and one new strand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

role of dna helicase

A

breaks the hydrogen bonds between nucleotides and unwinds the dna molecule

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

role of dna polymerase

A

forms the phosphodiester bonds between nucleotides

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

role of dna ligase

A

joins the fragments of dna, complementary to the lagging strand, together

21
Q

leading strand

A
  • parent strand of dna which runs in the 3’ to 5’ direction
  • able to be replicated continuously by dna polymerase
22
Q

lagging strand

A
  • parent strand of dna which runs in the 5’ to 3’ direction
  • replicated discontinuously (in fragments)
23
Q

steps in dna replication

A
  1. double helix is untwisted, a bit at a time
  2. H bonds between nucleotides are broken - catalysed by dna helicase
  3. results in 2 single strands of dna with exposed nucleotide bases
  4. free phosphorylated nucleotides in the nucleus pair up and bond with the exposed complementary bases
  5. dna polymerase catalysts the addition of the new bases, in the 5’ to 3’ direction
  6. leading strand is synthesised continuously whereas the lagging strand is in fragments that are later joined and catalysed by ligase enzymes
24
Q

product of dna replication

A
  • 2 dna molecules
  • each are identical to eachother and the parent molecule
  • each molecule contains one old strand and one new strand
25
Q

when do mutations occur

A

during dna replication

26
Q

what are point mutations

A
  • small errors occur (e.g the wrong nucleotide is inserted)
  • happen approx in every 1 in 10^8 base pairs
  • often edited out by enzymes later in the replication process
    —> they proofread and edit out incorrect nucleotides
27
Q

what happens when small errors aren’t edited out of the replication process

A

a slightly different version of the original gene may be produced (an allele)
—> can be beneficial, detrimental or have no impact

28
Q

what are beneficial and detrimental changes due to errors

A

BENEFICIAL - change has coded for a different AA which has changed the overall protein structure in a positive way
- has been advantageous for the organism
- e.g change in fur colour allows for better camouflaging

DETRIMENTAL - overall protein structure has changed in a negative way
- has been disadvantageous for the organism
- e.g change in enzyme structure meaning the organism can no longer digest key nutrition

29
Q

rna features

A
  • shorter and smaller than dna
  • single stranded
  • bases are C, G, A, U
  • less stable than dna
  • ribose pentose sugar
30
Q

rna function

A

retrieves info from dna to code for proteins synthesised in the cell’s ribosomes

31
Q

how do ribose and deoxyribose differ

A

ribose has an OH attached to the bottom of C2
deoxyribose has a H attached to the bottom of C2

32
Q

what is the genetic code

A

the sequence of bases along an organisms dna that tell the cell how to make a specific protein

33
Q

what is a codon

A

a sequence of 3 consecutive nucleotides in a dna/rna molecule that codes for a specific AA

34
Q

features of the genetic code

A
  • near universal: in almost all living organisms, the same dna triplet of bases codes for the same AA
  • degenerate: each AA is coded for by more than one triplet
    —> may reduce the effect of point mutations because a change in one base of the triplet could produce another base triplet that still codes for the SAME AA
  • non-overlapping: each base is only part of one triplet/codon and each triplet/codon codes for just one AA
35
Q

structure of ATP

A

3 phosophate groups
1 ribose sugar
1 adenine nitrogenous base

36
Q

what does ATP stand for

A

adenosine triphosphate

37
Q

function of ATP

A
  • used to power most energy requiring cellular reactions
  • transfers E from sites of respiration-> parts of the cell that require E
  • used by cells to transfer glucose molecules in smaller, more useful amounts
38
Q

hydrolysis of atp

A
  • when cell needs energy
    ATP + H2O —> ADP + Pi (+ energy)
  • 3rd inorganic phosphate group is released
  • catalysed by enzyme ATP hydrolase
  • the E released is used to perform work in the cell
  • can be coupled to other reactions within cell that need E
39
Q

resynthesis of atp

A
  • resynthesised by the condensation of ADP and Pi
    ADP + Pi (+ energy) —> ATP + H2O
  • catalysed by enzyme ATP synthase during photosynthesis or respiration
40
Q

mrna structure

A
  • single stranded
  • contains a ribose pentose sugar
  • contains C, G, A, U
  • small enough to leave nuclear pores
  • easily broken down
  • complementary to dna code
41
Q

mrna function

A
  • used to transfer the DNA code from the nucleus -> cytoplasm
  • once in cytoplasm, it associates with the ribosomes
  • used to determine the sequence of AAs during protein synthesis
42
Q

trna structure

A
  • small, single stranded
  • specific to one AA
  • folded into a clover leaf shape with one end of the chain slightly longer
    —> this longer section is attached to an AA
  • each has a sequence of 3 bases called an anticodon
    —> these are complementary to codons on the mrna molecule and it attaches here
43
Q

why does transcription happen

A

the instructions inside genes (on chromosomes) cannot pass out of the nucleus, so a copy of each gene has to be transcribed into a length of mrna

44
Q

transcription steps

A
  1. helicase breaks H bonds between bases
  2. polymerase moves along one of the strands (template strand)
  3. polymerase matches up complementary rna nucleotides
  4. as rna nucleotides join, pre mrna
  5. dna behind rna polymerase rejoins into double helix
  6. when rna polymerase reaches a ”stop” codon, chain is terminated , pre - mrna detaches
45
Q

result of transciption

A

pre - mrna, has the complementary sequence to the non-template/coding strand except all T vases are replaced with U bases

46
Q

what is the template strand also known as

A

the antisense strand or the noncoding strand

47
Q

what is the non template strand

A

it’s the coding strand because its sequence will be the same as that of the new rna molecule

48
Q

when does translation happen

A

when a molecule has been transcribed and it has then moved out of the nucleus (via a nuclear pore) to begin translation attached to a ribosome in the cytoplasm

49
Q

translation steps

A
  1. mrna attaches to a ribosome at the start codon
  2. trna attached to the mrna
  3. ribosome moves along mrna, reading the code. when 2 AAs are adjacent, a peptide bond forms between them
    5: ATP is needed for this polypeptide synthesis
  4. first trna is released and can collect another AA
  5. process is repeated till a “stop” codon is released
  6. mrna breaks down once polypeptide has been assembled
  7. newly synthesised protein is helped to fold correctly into its 3D shape tertiary structure

bio module 2 (3 decks)

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