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Biology Section 2 > DNA and RNA > Flashcards

DNA and RNA Flashcards

1
Q

What is heredity?

A

Characteristics passed on from parents to offspring in the form of genes

Example: Passing on of brown hair

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2
Q

Define gene.

A

A section of DNA that codes for a particular protein

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3
Q

What is gene expression?

A

A gene is expressed in the organism’s phenotype

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4
Q

How does gene expression manifest in phenotype?

A

E.g. a person has an allele for blue eyes but expresses brown eyes due to dominance

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5
Q

Define chromosome.

A

A structure composed of DNA and protein

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6
Q

What is the composition of chromosomes?

A
  • 60% protein
  • 40% DNA
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7
Q

How many pairs of chromosomes do humans have?

A

23 pairs

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8
Q

What is junk DNA?

A

DNA that does not code for a protein, also known as non-coding DNA

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9
Q

What percentage of DNA is considered junk DNA?

A

97%

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10
Q

Define exons.

A

Coding DNA in genes

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11
Q

Define introns.

A

Non-coding DNA in genes that fills the gaps between exons

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12
Q

What is the genetic code?

A

A sequence of bases in DNA that instructs the cell to produce a specific protein

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13
Q

What is a triplet/codon?

A

A sequence of 3 bases that code for a specific amino acid

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14
Q

Name the three types of codons.

A
  • Start codon
  • Stop codon
  • Amino acid codon
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15
Q

What does DNA stand for?

A

Deoxyribonucleic acid

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16
Q

What does RNA stand for?

A

Ribonucleic acid

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17
Q

What is DNA profiling?

A

The way in which DNA is analysed to find a matching sample

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18
Q

What is DNA extraction?

A

DNA is taken out from the cell as the cell is broken down

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19
Q

What is DNA cutting?

A

DNA is cut into different sized fragments using restriction enzymes

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20
Q

What do restriction enzymes do?

A

Cut DNA at particular combinations of nucleotides

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21
Q

What is electrophoresis?

A

The process of separating DNA fragments on the basis of length using an electric current in a gel

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22
Q

How does the size of DNA fragments affect their movement in gel electrophoresis?

A

Bigger cut pieces take longer to move and separate out in the gel

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23
Q

What happens during DNA transfer?

A

DNA is transferred from gel to filter paper

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24
Q

What is the purpose of analysis in DNA profiling?

A

To compare the pattern of bands of DNA formed to find a match

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25
List applications of DNA profiling.
* Forensic science (crime scene analysis) * Paternity tests
26
What is genetic screening?
Testing of a sample for the presence of a particular gene (or variant)
27
What can genetic screening help diagnose?
Genetic diseases
28
Who discovered the structure of DNA?
Watson and Crick
29
What is the structure of DNA?
A double helix structure - 2 strands of DNA joined together in a spiral shape
30
What is RNA composed of?
Nucleotides ## Footnote Each nucleotide has a 5 carbon sugar (deoxyribose), a phosphate, and a nitrogenous base.
31
What are the two types of nitrogenous bases in RNA?
Purines and pyrimidines ## Footnote Purines include Guanine and Adenine; pyrimidines include Cytosine and Thymine.
32
What is the structure of RNA?
Single strand ## Footnote RNA is composed of nucleotides with ribose sugar.
33
Which nitrogenous base in RNA replaces Thymine?
Uracil ## Footnote In RNA, Adenine joins with Uracil instead of Thymine.
34
What is mRNA?
Messenger RNA ## Footnote Carries information to code for a protein from DNA in the nucleus to ribosomes in the cytoplasm.
35
What is tRNA?
Transfer RNA ## Footnote It carries amino acids in the cytoplasm to the ribosomes and contains anticodons complementary to mRNA codons.
36
What role does rRNA serve?
Ribosomal RNA ## Footnote Forms part of the ribosome structure and helps match codons on mRNA with the appropriate amino acids.
37
What are codons?
Sequences of three nucleotides ## Footnote Each codon corresponds to a specific amino acid.
38
Fill in the blank: The bases in RNA join to each other using _______.
Hydrogen bonds
39
True or False: Adenine pairs with Thymine in RNA.
False ## Footnote In RNA, Adenine pairs with Uracil.
40
List the components of a nucleotide.
* 5 carbon sugar (ribose) * Phosphate * Nitrogenous base
41
What base does DNA contain?
Thymine (T) ## Footnote DNA contains four bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
42
What is the structure of DNA?
Double stranded (double helix) ## Footnote The double helix structure of DNA was first described by James Watson and Francis Crick.
43
Where is DNA found in the cell?
Nucleus ## Footnote DNA is primarily located in the nucleus, but some DNA can also be found in mitochondria.
44
Where does DNA replication take place?
In the nucleus ## Footnote DNA replication is a crucial process that occurs before cell division.
45
What base does RNA contain that DNA does not?
Uracil (U) ## Footnote In RNA, uracil replaces thymine found in DNA.
46
What is the structure of RNA?
Single stranded (single helix) ## Footnote RNA molecules are typically single-stranded and can fold into complex shapes.
47
What occurs during transcription?
A sequence of bases on DNA are copied to mRNA ## Footnote Transcription is the first step in gene expression, synthesizing mRNA from DNA.
48
What does RNA polymerase do?
Forms an mRNA strand ## Footnote RNA polymerase catalyzes the transcription of RNA from a DNA template.
49
What are codons?
Triplets of nucleotides on mRNA ## Footnote Codons specify which amino acid will be added during protein synthesis.
50
What types of codons are formed?
* Start * Stop * Amino acid ## Footnote Start codons signal the beginning of translation, while stop codons signal termination.
51
What is the significance of DNA replication?
DNA can make exact copies of itself that can be passed on to each new generation of cells ## Footnote This process is essential for growth, repair, and reproduction.
52
What happens during translation?
A sequence of bases on mRNA is used to create a sequence of amino acids ## Footnote Translation occurs in the ribosome and is the second step of gene expression.
53
Where does mRNA move after transcription?
To the cytoplasm ## Footnote Once mRNA is synthesized, it exits the nucleus and enters the cytoplasm for translation.
54
What role does tRNA play in translation?
Carries an anticodon which is complementary to a codon on mRNA ## Footnote tRNA molecules bring the appropriate amino acids to the ribosome during protein synthesis.
55
What does each tRNA molecule carry?
A specific amino acid ## Footnote The amino acids carried by tRNA are linked together to form proteins.
56
True or False: DNA replication results in identical double strands.
True ## Footnote Each new DNA molecule consists of one original and one new strand.
57
What does tRNA bring to the mRNA codon?
An amino acid
58
What happens to amino acids from the tRNA during protein synthesis?
They detach and bond together, forming a chain of amino acids
59
What role does tRNA play in the ribosome?
Pulls the mRNA through the ribosome
60
What is formed from the chain of amino acids after folding?
A functional protein
61
What is the first step to isolate DNA from plant tissue?
Chop up the onion
62
What is added to the onion to clump the DNA?
Salt
63
What is the purpose of adding washing-up liquid to the onion?
Breaks down the cell membrane and releases DNA
64
At what temperature and for how long should the beaker be placed in a water bath to denature enzymes?
60 degrees for 15 mins
65
What is the purpose of cooling the beaker in ice?
Stops any further breakdown of the DNA
66
How long should the mixture be blended to release DNA?
3 seconds
67
What type of filter is used to filter the mixture?
Coffee filter paper
68
What does protease do in the DNA isolation process?
Breaks down the proteins that surround the DNA
69
What is added to the test tube to make the DNA precipitate out of solution?
Ice cold ethanol
70
What is observed when twisting a glass rod in the test tube?
White stringy DNA strands are present
71
Fill in the blank: tRNA brings an _______ to the necessary mRNA codon.
amino acid
72
True or False: Blending the mixture for a longer period will not damage the DNA.
False

Biology Section 2 (9 decks)

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