Brainscape's Knowledge GenomeTM

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


See full index

Biology > Key Knowledge 2 > Flashcards

Key Knowledge 2 Flashcards

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

catalyst 

A

a substance capable of increasing the rate of a reaction without being used up

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

substrate 

A

the reactant of a reaction catalysed by an enzyme

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

reactant 

A

a molecule that undergoes a transformation into a product. When enzymes are involved, the reactant is called a substrate

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

product 

A

the transformed molecule created in a reaction

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

Features of enzymes (10)

A
  • Reusable
  • Specific
  • Reversible
  • Speed up, not create
  • Have an active site
  • Are proteins
  • Are a subset of catalysts
  • Act on entire biochemical pathways
  • End in ‘-ase’
  • Above the arrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

enzyme-substrate complex 

A

the structure formed when an enzyme and substrate are bound together

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

endonuclease 

A

an enzyme that breaks the phosphodiester bond between two nucleotides in a polynucleotide chain

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

recognition site 

A

a specific target of sequence of DNA upon which restriction endonucleases act

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

restriction endonuclease 

A

any enzyme that acts like molecular scissors to cut nucleic acid strands at specific recognition sites. Also known as a restriction enzyme

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

sticky end 

A

the result of a staggered cut through double-stranded DNA by an endonuclease resulting in overhanging nucleotides

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

blunt end 

A

the result of a straight cut across the double-stranded DNA by an endonuclease resulting in no overhanging nucleotides

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

overhanging nucleotides

A

unbonded nucleotides on the ends of the DNA strand resulting from a staggered cut

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

ligase 

A

an enzyme that joins molecules, including DNA or RNA, together by catalysing the formation of phosphodiester bonds

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

polymerase 

A

an enzyme that synthesises a polymer from monomers, such as forming a DNA strand from nucleic acids

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

primer 

A

a short, single strand of nucleic acids that acts as a starting point for polymerase enzymes to attach

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

CRISPR-Cas9 

A

a complex formed between gRNA and Cas9 which can cut a target sequence of DNA. Bacteria use this complex for protection from viruses and scientists have modified it to edit genomes

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

bacteriophage 

A

a virus that infects prokaryotic organisms

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

CRISPR-associated protein 9 (Cas9) 

A

an endonuclease that creates a blunt end cut at a site specified by guide RNA (gRNA)

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

CRISPR 

A

short, clustered repeats of DNA found in prokaryotes which protect them against viral invasion

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

spacer 

A

short sequences of DNA obtained from invading bacteriophages that are added into the CRISPR sequence

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

three steps to fighting the virus with the CRISPR-Cas9 system

A

exposure, expression, and extermination.

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

Exposure

A

the bacteriophage/virus injects its DNA into a bacterium, which identifies the viral DNA as a foreign substance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Expression

A

the CRISPR spacers are transcribed along with half a palindrome from the repeat either side of it, and converted into an RNA molecule known as guide RNA (gRNA).

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

Extermination

A

The CRISPR-Cas9 complex then scans the cell for invading bacteriophage DNA that is complementary to the ‘mugshot’ on the gRNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

protospacer adjacent motif (PAM) 

A

a sequence of two-six nucleotides that is found immediately next to the DNA targeted by Cas9

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

guide RNA (gRNA) 

A

RNA which has a specific sequence determined by CRISPR to guide Cas9 to a specific site

27
Q

blunt end

A

the result of a straight cut across the double-stranded DNA by an endonuclease resulting in no overhanging nucleotides

28
Q

genetic modification 

A

the manipulation of an organism’s genetic material using biotechnology

29
Q

gene therapy 

A

repairing genetic mutations by replacing a defective gene with a healthy one

30
Q

gene knockout 

A

a technique in gene editing where scientists prevent the expression of a target gene to understand its function in an organism

31
Q

deleterious mutation 

A

a change in DNA that negatively affects an individual

32
Q

steps to use CRISPR-Cas9 for gene editing

A
  1. Synthetic gRNA is created in a lab that has a complementary spacer to the target DNA that scientists wish to cut.
  2. A Cas9 enzyme is obtained with an appropriate target PAM sequence.
  3. Cas9 and gRNA are added together in a mixture and bind together to create the CRISPR-Cas9 complex.
  4. The gRNA-Cas9 mixture is then injected into a specific cell, such as a zygote.
  5. The Cas9 finds the target PAM sequence and checks whether the gRNA aligns with the DNA.
  6. Cas9 cuts the selected sequence of DNA.
  7. The DNA has a blunt end cut that the cell will attempt to repair.
  8. When repairing the DNA, the cell may introduce new nucleotides into the DNA at this site. Scientists may inject particular nucleotide sequences into the cell with the hope that it will ligate into the gap.
33
Q

gene knock-in 

A

a technique in gene editing where scientists substitute or add nucleotides in a gene

34
Q

differentiation 

A

the process in which cells develop specialised characteristics, typically transforming them from one cell type to another more specialised cell type

35
Q

CRISPR ethical concerns

A

• Safety – the possibility of off-target cleavages (edits in the wrong place) and mosaics (some cells containing edited genomes, others not) mean that many scientists are hesitant to use CRISPR outside of research.
• Informed consent – scientists cannot get consent from embryos to edit their genes. If the embryo goes on to be born and one day has children of its own, these children also will never have consented to scientists interfering with their genome.
• Inequality – there is concern that only wealthy people will be able to afford to use CRISPR to treat genetic conditions or otherwise change their genes.
• Discrimination – CRISPR may be a threat to those who are judged by society as biologically inferior, when in fact those individuals do not feel they need ‘fixing’ at all.

36
Q

polymerase chain reaction (PCR) 

A

a laboratory technique used to produce many identical copies of DNA from a small initial sample

37
Q

amplify 

A

to increase the quantity of a molecule by making many copies

38
Q

denature 

A

the disruption of a molecule’s structure by an external factor such as heat

39
Q

Taq polymerase 

A

a heat-resistant DNA polymerase enzyme isolated from the bacteria Thermus aquaticus, which amplifies a single-stranded DNA molecule by attaching complementary nucleotides

40
Q

elongate 

A

to synthesise a longer polynucleotide

41
Q

thermal cycler 

A

a laboratory apparatus which alters the temperature in pre-programmed steps for temperature-sensitive reactions like PCR

42
Q

anneal 

A

the joining of two molecules, for example two complementary DNA strands during the cooling phase of PCR

43
Q

process of PCR

A
  1. Denaturation – DNA is heated to approximately 90–95 °C to break the hydrogen bonds between the bases and separate the strands, forming single-stranded DNA.
  2. Annealing – the single-stranded DNA is cooled to approximately 50–55 °C to allow the primers to bind to complementary sequences on the single-stranded DNA.
  3. Elongation – the DNA is heated again to 72 °C, which allows Taq polymerase to work optimally. Taq polymerase binds to the primer, which acts as a starting point, and begins synthesising a new complementary strand of DNA.
  4. Repeat – the cycle (steps 1–3) is repeated multiple times to create more copies of DNA
44
Q

forward primer 

A

a DNA primer that binds to the 3’ end of the template strand and reads the DNA in the same direction as RNA polymerase

45
Q

reverse primer 

A

a DNA primer that binds to the 3’ end of the coding strand and reads the DNA in the reverse direction to RNA polymerase

46
Q

The process of gel electrophoresis

A
  1. The DNA samples are placed in the wells at one end of the gel using a micropipette.
  2. An electric current is passed through the gel using two electrodes – one positive, one negative. Since DNA is negatively charged due to the phosphate backbone, it is attracted to the positive electrode.
  3. Smaller DNA fragments move faster through the gel and so travel further than larger fragments, which don’t move as easily through the pores in the agarose.
  4. DNA is difficult to see with the naked eye so the gel is stained with a fluorescent dye such as ethidium bromide, allowing the bands of DNA to be visualised under an ultraviolet (UV) lamp.
47
Q

variations in molecular gel size is due to

A

• voltage – the stronger the electric force generated by the electrodes the further DNA travels towards the positive electrode
• gel composition – gels with a greater density and agarose concentration increase the difficulty for larger fragments to move through
• buffer concentration – the greater the concentration of ions in the buffer the more the electric current is conducted through the gel, which causes DNA to move further down the lane
• time – the longer the electric current is applied, the further the DNA will travel. Note: if too much time passes, the DNA may move out of the gel.

48
Q

genetic testing 

A

screening an individual’s DNA for anomalies that may make them susceptible to a particular disease or disorder

49
Q

DNA profiling 

A

the process of identification on the basis of an individual’s genetic information

50
Q

plasmid 

A

a small, circular loop of DNA separate from the chromosome, typically found in bacteria

51
Q

recombinant plasmid 

A

a circular DNA vector that is ligated to incorporate a gene of interest

52
Q

bacterial transformation

A

the process by which bacteria take up foreign DNA from their environment. Scientists use this process to introduce recombinant plasmids into bacteria

53
Q

gene of interest 

A

a gene scientists want to be expressed in recombinant bacteria. This gene often encodes a protein we wish to produce in commercial quantities. Also known as the desired gene

54
Q

vector 

A

a means of introducing foreign DNA into an organism. Plasmids are a popular vector in bacterial transformation

55
Q

plasmid vector 

A

a piece of circular DNA that is modified to be an ideal vector for bacterial transformation experiments

56
Q

four important DNA sequences of a plasmid vector

A

• Restriction endonuclease sites – a site on the plasmid that can be recognised and cut by a restriction endonuclease, allowing the gene of interest to be inserted.
• Antibiotic resistance genes – e.g. ampR which confers ampicillin resistance or tetA which confers tetracycline resistance.
• Origin of replication (ORI) – a sequence that signals the start site for DNA replication in bacteria.
• Reporter gene – genes with an easily identifiable phenotype that can be used to identify whether a plasmid has taken up the gene of interest.

57
Q

heat shock 

A

a method that involves rapidly increasing and decreasing the temperature to increase membrane permeability in order to enhance the likelihood of bacterial transformation

58
Q

electroporation 

A

a method that involves delivering an electric shock to bacterial membranes to increase their membrane permeability and increase the likelihood of bacterial transformation

59
Q

 Production and extraction of recombinant insulin

A
  1. Plasmid vector produced with ampR, lacZ, and BamHI restriction site
  2. Insulin A and B subunit genes cut and ligated to form recombinant plasmids
  3. Solution of bacteria transformed via heat shock or electroporation
  4. Bacteria transformed with recombinant plasmid isolated from an agar culture
  5. Insulin subunit gene expressed with a β-galactosidase tail from lacZ remnant sequence
    6&7. Insulin A and B subunit proteins isolated, purified, and combined to form functional human insulin
60
Q

genetic engineering 

A

the process of using biotechnology to alter the genome of an organism, typically with the goal of conferring some desirable trait

61
Q

genetically modified organism (GMO) 

A

an organism with genetic material that has been altered using genetic engineering technology

62
Q

cisgenic organisms 

A

a genetically modified organism that contains foreign genetic material from a sexually compatible donor organism, typically from the same species

63
Q

transgenic organism 

A

a genetically modified organism that contains foreign genetic material from a separate species (or recombinant DNA from the same species that has been manipulated before introduction)

64
Q

creating transgenic plants for agriculture process

A

1 Gene identification: firstly, a particular gene of interest must be identified and isolated.
2. Gene delivery: next, the isolated gene of interest must be delivered into the cells of the host organism.
3. Gene expression: the transformed cell is then grown repeatedly (regenerated) using plant tissue cultures under sterile conditions before being applied in the field for agricultural us

Biology (13 decks)

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