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BIOMED FEEDBACKS QS > molecular biology > Flashcards

molecular biology Flashcards

1
Q

DNA

A

deoxyribonucleic acid

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2
Q

What is a gene?

A

an inheritance unit that helps determine a trait

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3
Q

genome

A

The complete set of genetic material in an organism

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4
Q

DNA contains 4 different types of bases

A

adenine
thymine
guanine
cytosine

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5
Q

Explain basic DNA structure in terms of sugars

A

bases and phosphates,

Nitrogenous bases are attached to a sugar-phosphate backbone

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6
Q

Explain the central dogma of molecular biology

A

Involves DNA replication, transcription and translation in order to make proteins

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7
Q

Explain “the information for making a new strand of DNA comes from an old strand of DNA”

A

In DNA replication, An old strand of DNA becomes a template to create a new complementary strand

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8
Q

transcription

A

synthesis of RNA from DNA template where the code in the DNA is converted into a complementary RNA code

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9
Q

Explain the steps involved in transcription

A
  • Before transcription can take place, the DNA double helix must unwind near the gene that is getting transcribed. One strand, the template strand, serves as a template for synthesis of a complementary RNA transcript. The other strand, the coding strand, is identical to the RNA transcript in sequence, except that it has uracil (U) bases in place of thymine (T) bases.
  • The RNA transcript is read to produce a polypeptide.
  • If the gene that’s transcribed encodes a protein (which many genes do), the RNA molecule will be read to make a protein in a process called translation.
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10
Q

translation

A

synthesis of a protein from an mRNA template where the code in the mRNA is converted into an amino acid sequence in a protein

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11
Q

Explain the steps in translation

A
  • Initiation: in this stage, the ribosome gets together with the mRNA and the first tRNA so translation can begin.
  • Elongation: in this stage, amino acids are brought to the ribosome by tRNAs and linked together to form a chain.
  • Termination: in the last stage, the finished polypeptide is released to go and do its job in the cell.
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12
Q

What is a codon?

A

A sequence of three nucleotides which together form a unit of genetic code in DNA or RNA

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13
Q

What is meant by genetic code?

A

The genetic information carried by DNA and RNA in living cells

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14
Q

What are two differences between RNA polymerases and DNA polymerases?

A
  • RNA polymerase does not need a primer but DNA polymerase does
  • DNA polymerase synthesises DNA for transcription and RNA polymerase synthesises mRNA during transcription
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15
Q

What is a restriction enzyme?

A

Enzymes that cut a DNA molecule at a particular location

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16
Q

What is a Ligase enzyme?

A

Joins DNA strands together

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17
Q

How can PCR be used in sex determination?

A

Set up a PCR reaction as normal, attach appropriate primers to female DNA and male DNA. The annealing sites of these primers means that the female DNA (including XX chromosomes) will produce 1 band of 488 base pairs, and male DNA (including XY chromosomes) will produce one band of 488 base pairs, and one pair of 340 base pairs

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18
Q

What are 3 other applications of PCR?

A
  • Diagnosis of genetic disease
  • Archaeology to identify human or animal remains
  • Forensics
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19
Q

Describe the steps of PCR

A

Denaturing: Heating DNA to approx. 95 degrees to break the hydrogen bonds between the double strands of DNA and create two single strands
Annealing: Attaching primers to the DNA strands to determine where polymerase will start attaching base pairs at 50-75 degrees
Extension: Polymerase adds base pairs to each strand in order to create two double stranded DNA molecules at 72 degrees

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20
Q

Are there any infectious disease causing agents that can not be detected using a PCR type reaction? If so name one such agent or disease.

A

Yes, PCR is used to amplify DNA, so disease causing agents that do not have DNA (e.g. prions) are hard to detect with PCR Electrophoresis

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21
Q

When electrophoresed over a given period of time will a small DNA molecule usually migrate a shorter distance or a further/longer distance through an agraose gel, compared to a large DNA molecule?

A

Longer will go less distance and short will travel further

22
Q

smaller molecules travel faster through agarose gel than larger molecules. true or false

A

true

23
Q

True or False? “electrophoresis can separate molecules based on both size and charge”

A

true

24
Q

What types of molecules can be separated using Electrophoresis?

A

DNA

25
Q

A certain type of PAGE can be used to separate denatured proteins. What are denatured proteins?

A

Denatured proteins are proteins that proteins that have disrupted/destroyed secondary and tertiary structures, and are only left with their primary structure

26
Q

What is meant by the term “metabolism”?

A

A sequence of enzyme catalysed chemical reactions in the cell - both anabolic and catabolic reactions

27
Q

Anabolic and catabolic pathways are different. Explain two of the differences between an anabolic pathway and a catabolic pathway.

A

Anabolic: Concerned with the processes involved in the assembly of complex organic molecules, requires energy and has divergent pathway
Catabolic: Processes related to degradation of complex substances, with resulting generation of energy, conserves energy and has a convergent pathway

28
Q

What is an enzyme?

A

Catalysts that regulate the chemistry of cells and organisms

29
Q

What is an enzyme active site?

A

Part of enzyme involved in the catalytic reaction

30
Q

When referring to an enzymatic reaction what is meant by the term “substrate”?

A

The reactant in an enzyme-catalysed reaction (Substance acted upon by the enzyme)

31
Q

When referring to an enzymatic reaction what is meant by the term “product”?

A

What is produced after the enzyme and substrate have bonded together

32
Q

List and explain four (4) variables that can effect enzyme activity.

A
  • Temperature: Each enzyme has an optimum temperature, and can only work within a certain range of temperatures.
  • pH: Each enzyme has an optimum pH, and can only work within a certain range of pH levels.
  • Substrate concentration: The more substrates that bind with available enzymes, the faster the reaction.
  • Enzyme concentration: The greater the number of enzymes that are able to bind with a substrate the faster the reaction.
33
Q

A laboratory assay uses an enzymatic reaction as part of the assay procedure. Explain why the incorrect incubation time for the laboratory assay may effect the results of the assay

A

This could affect the temperature that the enzyme is working in, and the enzyme may not be able to work effectively.

34
Q

List 4 different types of biological specimens that may be used in a Biomedical Science or Pathology laboratory.

A
  • Blood
  • Urine
  • Faeces
  • Solid tissue
35
Q

Name the cellular components of blood

A

RBC
WBC
platelets

36
Q

Name 3 components of blood required for clotting

A
  • Ca2+
  • Platelets
  • Clotting proteins e.g. fibrinogen
37
Q

Is there a difference between serum and plasma? Explain your answer.

A

Plasma: liquid portion of blood
Serum: liquid portion of blood without clotting components

38
Q

What is an anticoagulant?

A

A substance that allows the plasma portion of blood to be separated from the rest

39
Q

List one anticoagulant and explain its mode of action.

A

Heparin: inhibits clotting proteins (eg thrombin)

40
Q

Why are different anticoagulants used when collecting blood?

A

Different coagulants have different purposes and modes of action, e.g. sodium fluoride preserves glucose in blood and oxalate joins calcium ions together.

41
Q

Why is correct identification of a patient sample important?

A

So that the patient waiting for results does not get an incorrect diagnosis, treatment or intervention.

42
Q

List 2 reasons that a patient sample may be unsuitable for a laboratory assay necessitating the recollection of a sample

A
  • If the patient is identified incorrectly

- If the sample is damaged while being transported

43
Q

Haemophilia is a disease studied in a Coagulation laboratory. What is Haemophilia?

A

A blood disorder where blood is not able to clot properly

44
Q

Why might a protein need to be separated from a mixture of other proteins?

A

There may only be one protein that you need in order to complete your analysis/testing

45
Q

What types of molecules can be separated from a mixture using Chromatography?

A

DNA
RNA
other organic molecules

46
Q

List three Chromatography principles that can be used to separate a molecule of interest from a mixture

A

Ion Exchange: Solid stationary phase and liquid mobile phase
Size Exclusion: Liquid stationary phase and liquid mobile phase
Affinity: Stationary ligand and liquid mobile phase

47
Q

For each of the 3 chromatography principles what property of the molecule of interest is being utilised (eg size, charge, etc)

A

Ion exchange: charge

Size exclusion: size

48
Q

What factors may affect the reliability of a laboratory test result?

A

Accuracy and precision

49
Q

Explain the term Accuracy when referring to laboratory results

A

Closeness of measured value to true value

50
Q

Explain the term Precision when referring to laboratory results

A

How close together a set of measurements (of the same parameter) are to each other

BIOMED FEEDBACKS QS (7 decks)

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