Unit 3 (Molecular Biology) Flashcards

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1
Q

What is DNA? What does it stand for?

A
  1. A double-stranded polymer of nucleotides
  2. Deoxy-ribo-nucleic acid
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2
Q

How many types of nucleotides are there? What are their names?

A
  1. There are four types
  2. (Adenine, Thymine, Cytosine, Guanine)
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3
Q

Opposite DNA strands are complimentary to each other, what are two reasons this is important?

A
  1. This enables “self-replication” (mitosis)
  2. This enables the synthesis of temporary, single-stranded copies of each strand (RNA)
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4
Q

What is a chromosome?

A

A very long DNA molecule.

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5
Q

What is a gene?

A

A section of a chromosome that encodes the amino acid sequence of proteins. (gene=recipe for protein)

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6
Q

Are all genes recipes for proteins?

A

No. Most are, but some are known as “noncoding RNAs.” These genes code for RNA that have other functions.

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7
Q

What is DNA Replication?

A

DNA Replication happens during mitosis, and is the creation of a second identical chromosome (DNA molecule).

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8
Q

What is RNA?

A

A single stranded polymer of nucleotides

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9
Q

List three ways RNA different from DNA.

A
  1. The sugar is ribose
  2. RNA is single stranded and base pairs with itself forming complex globular shapes (like proteins)
  3. Instead of thymine (T), RNA has uracil (U)… both pair with Adenine.
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10
Q

What is a nucelotide (made of)?

A

A nitrogenous base, a sugar molecule, and a phosphate group.

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11
Q

What connects the two polymers in DNA?

A

The polymer of nucleotides connect via the nitrogenous bases. They are held by a hydrogen bond.

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12
Q

What does it mean for two strands to be “complimentary?”

A

This means that the two strands will always complement each other. (have it’s matching nitrogenous base)

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13
Q

How many hydrogen bonds are between Adenine and Thymine? How many between Guanine and Cytosine?

A

A-T (2 hydrogen bonds)
C-G (3 hydrogen bonds)

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14
Q

What is “non-coding RNA?”

A

RNA that has a function other than making a protein.

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15
Q

What does semiconservative mean?

A

Each of the DNA strands made through replications is one strand of old DNA and one strand of new DNA. This makes it “semiconservative.”

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16
Q

What are the steps of DNA replication?

A
  1. enzymes unwind and unzip the helix
  2. new complementary strands are synthesized
  3. We have two identical DNA molecules
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17
Q

When DNA replicates, how is the new strand synthesized?

A

The DNA Polymerase is the enzyme that makes a new copy of both strands.

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18
Q

What is RNA? What does it stand for?

A
  1. A single stranded polymer of nucleotides (a copy of a bit of DNA)
  2. Ribonucleic Acid
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19
Q

In RNA the sugar is slightly different. How so?

A

The hydrogen in DNA is replaced with a hydroxide ion.

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20
Q

The hydroxide ion in RNA serves four “purposes”. What are they?

A
  1. It is very reactive. (bonds to other molecules easily)
  2. It allows some RNA molecules to be catalytic (capable of action) and perform actions.
  3. RNA can store genetic info.
  4. According to the “RNA World” Hypothesis, RNA evolved before DNA.
    (RESA)
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21
Q

What are enzymes?

A

Proteins that speed up chemical reactions.

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22
Q

What is an example of a catalytic RNA molecule.

A

Ribosomes

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23
Q

What are two examples of RNA base-pairing with itself? What shapes are made from this?

A
  1. tRNA (looks like a t)
  2. rRNA (globular)
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24
Q

What is the difference between RNA Polymerase and DNA Polymerase?

A

RNA Polymerase= Synthesizes RNA
DNA Polymerase= Synthesizes makes a copy of an existing DNA strand for DNA replication

25
Q

What is Transcription?

A

RNA Synthesis (the making of RNA from DNA)

26
Q

What are the two things RNA can be?

A
  1. A copy of a protein recipe (mRNA)
  2. It can also help synthesize proteins (rRNA, tRNA)
27
Q

What are (mRNA) (rRNA) (tRNA)?

A
  1. M= copy of a protein recipe (messenger)
  2. R= a component of ribosomes (ribosomal)
  3. T= synthesize a protein (transfer)
28
Q

What is Translation?

A

Protein Synthesis (the making of proteins)

29
Q

What is a ribosome made out of? What do they do?

A
  1. rRNA+protein
  2. Synthesize proteins
30
Q

What are proteins made out of? What is mRNA made out of?

A
  1. Proteins are made linear sequences (polymer) of amino acids.
  2. A linear sequence of (polymer) nucleotides.
    (They speak two different “languages”?) 🧡
31
Q

What is CRISPR/Cas9 System?

A

A new tool for “genome editing.”

32
Q

What are four main examples of things we’ve genetically modified using CRISPR, and what they have achieved?

A
  1. Cultured Plant Cells-> new crops
  2. Fertilized Eggs-> new animals
  3. Stem Cells-> new medical treatments
  4. Blood Cells
    (PESB)
33
Q

What is a Bacteriophage?

A

A type of virus.

34
Q

What is the natural phenomenon that CRISPR uses to edit genes?

A

Some prokaryotes have an immune system that defends against bacteriophages.

35
Q

What are four possible uses of gene drives?

A
  1. To make malaria-resistant mosquitoes (can’t carry malaria anymore)
  2. To eliminate invasive species
  3. To reverse pesticide resistance in weeds and insects
  4. To make species-specific poisons
36
Q

What is a type of gene drive modification to prevent gene drives gone wild?

A

A self-extinguishing drive (also known as a daisy drive.)

37
Q

What are four autosomal recessive genetic disorders?

A
  1. Cystic Fibrosis
  2. Sickle-Cell Anemia
  3. Albinism
  4. Phenylketonuria
    (CSAP)
38
Q

What is Sickle-Cell Anemia? What population is it most common in?

A
  1. A autosomal recessive genetic disorder.
  2. 1/600 blacks, 1/12 are carriers
39
Q

What are black people more likely to have/carry sickle-cell anemia?

A

Carriers (heterozygotes) of sickle-cell have resistance to malaria. Malaria is very common in Africa.

40
Q

What is Heterozygote Superiority?

A

Where the heterozygote trait is the most beneficial (evolutionarily).

41
Q

What is Phenylketonuria? What will happen if it’s not treated? How do you treat it?

A
  1. An autosomal recessive disorder in with the individual can’t degrade (break apart) excess phenylalanine.
  2. If phenylalanine intake is not controlled the individual will suffer from severe brain damage
  3. One must control their diet to intake the correct amount of phenylalanine.
42
Q

What are four examples of X-Linked Recessive genetic disorders?

A
  1. Red-green color blindness
  2. Hemophilia
  3. Duchene Muscular Dystrophy (DMD)
  4. Huntington’s Disease
43
Q

What is Dichromatic Vision?

A

The fancy name for red-green color blindness.

44
Q

What amino acid is the start codon always?

A

Methionine

45
Q

What is an Anticodon?

A

The tRNA codon that pairs with the mRNA codon.

46
Q

What is a Codon?

A

Three nucleotides on an RNA molecule.

47
Q

What does a Peptide Bond do?

A

This is the covalent bond that connects amino acids

48
Q

What are the two units that make up a Ribsome?

A

There are two Ribsomal Subunits, the large one and the small one.

49
Q

How does a ribosome know when to stop making a protein? What happens to the mRNA when the ribosome doesn’t need it anymore?

A
  1. They will reach the stop codon on the mRNA molecule.
  2. The mRNA molecule will disassemble.
50
Q

What is the rate at which amino acids are assembled? How many amino acids are typically in a protein?

A
  1. Ribosomes assemble about 2 amino acids a second.
  2. There are typically 300 amino acids In a protein.
51
Q

What is a Mutation?

A

A change in the nucleotide sequence of DNA.

52
Q

What are the three possible causes of a mutation?

A
  1. Enzyme Error
  2. Mutagens
  3. A Virus
53
Q

What is an Enzyme Error? When does it take place?

A
  1. An enzyme error is when an enzyme makes a mistake in assembling nucleotides.
  2. During DNA replication or repair. Or when the DNA “crosses over.”
54
Q

What are the four types of Mutagens?

A
  1. Radiation (wavelengths)
  2. Chemical
  3. “Natural”
  4. Man-made (industrial byproducts)
55
Q

What are two examples of Natural Mutagens?

A
  1. Free Radicals (molecules with an unpaired electron-very aggressive)
  2. Radon Gas (a radioactive element)
56
Q

What is an example of a virus that can cause a mutation?

A

HPV has been linked to causing throat and cervical cancer.

57
Q

Give an example of a type of Mutation.

A

A Point Mutation (in which only a single nucleotide mutates)

58
Q

What are the three possible results of a mutation?

A
  1. A harmful result (new bad trait)
  2. A helpful result (new good trait)
  3. Neither (new neutral trait)
59
Q

Why are most mutations neutral?

A

Because 95% of our genome is considered “non-coding DNA”