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Biology 100 > Chapter 6: DNA > Flashcards

Chapter 6: DNA Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

DNA

A

Deoxyribonucleic acid

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2
Q

What is a nucleic acid?

A

Molecules that store information

DNA

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3
Q

What is the connection between DNA and chromosomes?

A

DNA exists as long fibers called chromosomes, which contain genes.

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4
Q

Polymer

A

A large molecule made by repeating a smaller unit

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5
Q

What are the polymers in DNA called?

A

Nucleotides

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6
Q

How many chromosomes do humans have?

A

46; 23 pairs

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7
Q

DNA helicase breaks which type of bond in the DNA molecule?

A

Hydrogen bonds

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8
Q

The overall structure of DNA is a…

A

Double helix

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9
Q

What does a nucleotide contain?

A

A central five-carbon sugar (deoxyribose in DNA), a negatively charged phosphate, and a base made from one or two rings of nitrogen and carbon.

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10
Q

T/F: The sugar and phosphate are identical among all DNA nucleotides

A

True

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11
Q

Polynucleotide

A

A polymer made up of many nucleotides covalently bonded together. Contained in one molecule of DNA.

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12
Q

T/F: A polynucleotide can contain any combination of the four bases along its length

A

True

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13
Q

An A-T base pair is held together by how many hydrogen bonds?

A

2

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14
Q

A C-G base pair is held together by how many hydrogen bonds?

A

3

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15
Q

DNA Replication

A

The process by which a DNA molecule is copied

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16
Q

DNA replication is said to be semi-conservative because…

A

Each new molecule conserves half of the original molecule

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17
Q

Describe the first step in DNA replication

A

The double helix is peeled apart by the enzyme helicase. This forms a “replication bubble” where the bases in each separate DNA strand are exposed.

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18
Q

Describe the second step in DNA replication

A

DNA polymerase binds the two separate DNA strands together. Using the original strand as a template, DNA polymerase matches the correct bases together.

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19
Q

Describe the third step in DNA replication

A

DNA ligase fuses the two individual fragments into a final DNA molecule

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20
Q

What are the two types of nucleic acids found in all living cells?

A

DNA and RNA

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21
Q

What does RNA stand for?

A

Ribonucleic acid

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22
Q

What are the similarities between DNA and RNA?

A
  1. Both are polymers of nucleotides
  2. Each consists a sugar
  3. Both have phosphates
  4. Both have bases
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23
Q

What are the three structural differences between DNA and RNA?

A
  1. DNA is double stranded; RNA is single stranded
  2. The sugar is DNA is deoxyribose; the sugar in RNA is ribose
  3. DNA has Thymine base; RNA has Uracil base
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24
Q

How does DNA direct the production of proteins?

A

DNA first produces RNA, which manufactures the production of proteins

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25
Q

T/F: DNA produces your appearance

A

False; DNA produces proteins that are responsible for physical traits

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26
Q

How does genetic information flow from DNA to RNA to protein?

A

Flow of information starts in the DNA in the nucleus; information encodes into RNA that leaves the nucleus; RNA is used to produce proteins using ribosomes in the cytoplasm.

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27
Q

Transcription

A

The synthesis of RNA on a DNA template

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28
Q

How does RNA leave the nucleus?

A

Through an opening in the nuclear envelope called the nuclear pore.

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29
Q

Translation

A

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule

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30
Q

Messenger RNA (mRNA)

A

A ribonucleic acid that encodes genetic information from DNA and encodes it to ribosomes

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31
Q

Codon

A

A three-nucleotide sequence in mRNA that specifies a particular termination signal; the basic unit of the genetic code

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32
Q

In eukaryotic cells, transcription takes place in the…

A

nucleus

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33
Q

Describe the first step on transcription

A

An enzyme called RNA polymerase binds to a promoter, which is a “start here” signal for the beginning of a gene

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34
Q

Describe the second step in transcription

A

RNA polymerase synthesizes a molecule of RNA; A matches with T, U matches with A, C matches with G, G matches with C

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35
Q

Describe the third step in transcription

A

Introns are removed, eons are joined together (RNA splicing)

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36
Q

What is the fourth step of transcription?

A

mRNA leaves the nucleus

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37
Q

Translation takes place in what part of the cell?

A

Ribosomes within the cytoplasm

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38
Q

Ribosomal RNA (rRNA)

A

The type of nucleic acid that makes ribosomes along with proteins. It is the most abundant type of RNA

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39
Q

Transfer RNA (tRNA)

A

An interpreter in translation. The specific anticodons pick up an amino acid and and conveys the appropriate codon.

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40
Q

Anticodon

A

On a tRNA molecule, a sequence of three nucleotides that is complementary to a codon

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41
Q

Triplet code

A

The correspondence between an mRNA codon and its amino acid

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42
Q

What is the specific start codon?

A

AUG

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43
Q

What are the three stop codons?

A

UAA, UAG, UGA

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44
Q

Where are the binding sites for mRNA and tRNA?

A

In ribosomes

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45
Q

Initiation

A

The first step of translation. An mRNA molecule binds to a small ribosomal subunit. tRNA then binds to the “start” codon

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46
Q

Elongation

A

The second step of translation. The polypeptide grows longer due to the newly made amino acids from tRNA and mRNA. That tRNA molecule then leaves the cell, making room for the next one.

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47
Q

Termination

A

The final step in translation. The ribosome disassembles once it reaches a “stop” codon on an mRNA.

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48
Q

What is the first step of gene expression?

A

Transcription

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49
Q

What is NOT a modification to the mRNA?

A

Promoter binding

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50
Q

RNA polymerase is transcribing a segment of DNA that contains the sequence shown below, using the upper strand as template. What will the sequence of this segment of RNA be?

5’­GATCTACGTA­3’
3’­CTAGATGCAT­5’

A

UACGUAGAUC

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51
Q

Name the process of PCR in order

A
  1. Start with a sample of double-stranded DNA
  2. Heat sample to two DNA strands
  3. DNA polymerase duplicates DNA strands
  4. Cool sample to allow DNA helices to form
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52
Q

Which of the following is FALSE regarding X-­Chromosome inactivation?

A

Inactivated X chromosome happens in the Zygote

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53
Q

Which part of a nucleotide molecule in DNA encodes genetic information?

A

The base

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54
Q

Which nucleic acid acts like an enzyme, stabilizing and orienting different molecules to facilitate the formation of bonds between them?

A

rRNA

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55
Q

How is translation initiated?

A

Two ribosomal subunits bind to the mRNA transcript.

56
Q

PCR is used to copy just a relatively small region of DNA, not the entire genome. How do researchers specifically target the region of interest?

A

They use two primers, each about 15 to 20 nucleotides long, that flank the region of interest.

57
Q

T/F: Both genetically modified plants and animals make up a significant part of our food supply.

A

False

58
Q

When is cell­-to-­cell communication particularly important in regulating gene expression?

A

During embryonic development

59
Q

Puberty is caused by the release of follicle stimulating hormone and luteinizing hormone from the pituitary gland. These hormones are delivered to the ovary in girls and initiate the monthly release of mature egg cells. This is an example of what mechanism of regulation of gene expression?

A

A typical signal transduction pathway

60
Q

The small circular molecules of DNA commonly found in bacteria are called…

A

Plasmids

61
Q

Gel electrophoresis separates DNA fragments according to their…

A

Length

62
Q

T/F: Standard STR analysis of a DNA sample from a crime scene and DNA from a suspect shows matches at four sites. The suspect is guilty.

A

False

63
Q

Where does the bond form that binds one strand of DNA to its other strand?

A

Between the bases

64
Q

Do all cells of the body express the same genes?

A

No, since they don’t all need to make the same proteins

65
Q

T/F: During transcription of a specific gene, only one DNA strand serves as a template for the formation of RNA.

A

True

66
Q

Which enzyme is responsible for adding complementary DNA bases to an exposed DNA strand?

A

DNA polymerase

67
Q

After DNA replication…

A

Each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand

68
Q

What is the role of primers in the PCR techniques?

A

To target specific areas of DNA

69
Q

Gene cloning is used to…

A

Produce large quantities of human proteins

70
Q

Finding a male calico cat is…

A

Not impossible, but rare. X-chromosome inactivation can sometimes happen in males, but mostly females

71
Q

What is the monomer of the DNA molecule?

A

Nucleotide

72
Q

Gene regulation

A

The turning on and off of specific genes within a living organism

73
Q

Gene expression

A

The process whereby genetic information flows from genes to proteins; the flow of genetic information from the genotype to the phenotype: DNA → RNA → protein.

74
Q

What happens if a chromosome is condensed?

A

The many genes that it contains are inaccessible and won’t be able to produce proteins

75
Q

X-chromosome inactivation

A

In female mammals, the inactivation of one X-chromosome in a somatic cell. All descendants have the same copy of X-chromosome inactivation

76
Q

Barr body

A

A dense body formed from a deactivated X chromosome found in the nuclei of female mammalian cells.

77
Q

Transcription factors

A

A series of proteins that must bind to DNA before transcription can begin

78
Q

Intron

A

Noncoding regions that are spliced out

79
Q

Exon

A

Coding regions that are pasted together, forming multiple mRNAs

80
Q

What ways can the RNA transcribed from a gene be altered?

A
  1. A cap and a tail are added
  2. Introns are spliced out and eons are pasted together. Several mRNAs can be produced from a single gene
  3. microRNAs bind to RNA molecules and prevent them from producing protein
81
Q

Signal transduction pathway

A

A series of molecular changes that converts a signal received on a target cell’s surface to a specific response inside the cell.

82
Q

What is the usual result of a signal transduction pathway?

A

Turning off one or more genes. A new protein is made from the signal

83
Q

Development

A

The growth and specialization of cells and tissues that occur as the cells of a zygote multiply and differentiate to form a multicellular organism. An important example of cell-to-cell signaling

84
Q

Induction

A

Occurs when one group of cells influences the development of the adjacent group of cells

85
Q

Homeotic genes

A

Master control genes; helps with the development of an overall structure in an organism

86
Q

Mutation

A

Any change in the nucleotide sequence of DNA

87
Q

Mutagen

A

A chemical or physical agent that interacts with DNA and causes a mutation.

88
Q

Carcinogen

A

Cancer-causing agents

89
Q

Point mutation

A

A change in a single nucleotide pair of a gene.

90
Q

Silent mutation

A

Does not change the amino acid produced

91
Q

Missense mutation

A

Substituting one amino acid for another

92
Q

Nonsense mutation

A

Changes an amino acid codon into a stop codon, resulting in a shorter defective protein

93
Q

T/F: A codon is three consecutive nucleotides

A

True

94
Q

Insertion

A

Mutations that add nucleotides

95
Q

Deletions

A

Mutations that remove nucleotides

96
Q

Frameshift mutation

A

When an insertion or deletion throws off a reading frame

97
Q

Sickle-cell disease is caused by…

A

The replacement of an A with a T at the 17th nucleotide of one of the genes for hemoglobin

98
Q

Tumor

A

An abnormal mass of cells that forms within otherwise normal tissue.

99
Q

Cancer

A

A malignant growth or tumor caused by abnormal and uncontrolled cell division.

100
Q

Cell cycle control system

A

A cyclically operating set of proteins that triggers and coordinates events in the eukaryotic cell cycle.

101
Q

Cell cycle control system

A

A cyclically operating set of proteins that triggers and coordinates events in the eukaryotic cell cycle.

102
Q

Oncogene

A

A gene that leads to uncontrolled cell growth

103
Q

Growth factor

A

A protein secreted by certain body cells that stimulates other cells to divide.

104
Q

Tumor supressor gene

A

A gene whose product inhibits cell growth

105
Q

Cancer is defined as…

A

Abnormal growth of the body’s own cells

106
Q

Cancer begins within…

A

A single cell when multiple photo-oncogenes into oncogenes

107
Q

Metastasis

A

The spread of cancer cells from their site of origin to sites distant in the body

108
Q

Proto-oncogenes

A

Normal, necessary genes that help regulate cell growth

109
Q

A typical genetic engineering challenge is…

A

To produce large quantities of a desired human protein

110
Q

Gene cloning

A

The production of multiple copies of a gene

111
Q

Restriction enzyme

A

DNA cutting enzymes that only target specific nucleotide sequences

112
Q

Examples of humans manipulating nature

A
  1. Biotechnology
  2. DNA technology
  3. Genetic engineering
113
Q

Restriction site

A

A specific DNA sequence recognized by a particular restriction enzyme

114
Q

Sticky ends

A

The result of restriction enzymes, fragments with single-stranded regions which can join to other pieces of DNA

115
Q

Recombinant DNA

A

A DNA molecule containing nucleotides from more than one source

116
Q

Genome

A

An organism’s entire set of DNA

117
Q

Genomic library

A

A collection of cloned DNA fragments that include the organism’s entire genome

118
Q

What role does DNA ligase play in the manipulation of DNA?

A

DNA ligase pastes DNA fragments onto plasmids

119
Q

Nucleic acid probe

A

A complementary molecule that helps visualize the target DNA

120
Q

Reverse transcriptase

A

An enzyme that can synthesize DNA molecules from the collection of mRNAs within a cell

121
Q

Complementary DNA (cDNA)

A

The result of reverse transcriptase; represents just the genes that were producing proteins in the cell at that time. Results in a gene with only exons

122
Q

Genetically modified organisms (GMOs)

A

Ones that have acquired one or more genes by artificial means

123
Q

Transgenic organism

A

An organism that contains genes from another organism, typically another species

124
Q

What is the relationship between producing a GMO and plasmids?

A

Plasmids act as a temporary DNA carrier, allowing genes to be inserted into another

125
Q

Polymerase chain reaction (PCR)

A

A laboratory technique by which a specific segment of DNA can be targeted and copied quickly and precisely

126
Q

What is the key to PCR?

A

DNA polymerase, because it synthesizes the new strands of DNA

127
Q

DNA polymerase

A

An enzyme that synthesizes a new strand of DNA that is complementary to the original

128
Q

Primers

A

Artificially created, single-stranded DNA that bind to a target sequence

129
Q

DNA profiling

A

Allows an investigator to determine with certainty whether two samples of DNA came from the same individual

130
Q

Short tandem repeats (STRs)

A

Sites where a short nucleotide sequence is repeated many times in a row

131
Q

STR analysis

A

A comparison of the length of STRs

132
Q

Gel electrophoresis

A

Allows visualization of DNA samples based on length

133
Q

How identical are the genomes of two humans?

A

99.5%

134
Q

How much of human DNA codes for proteins?

A

1.5%

135
Q

24% of human DNA…

A

Consists of sequences that control genes but are not genes themselves

136
Q

59% of human DNA…

A

Is repetitive

Biology 100 (3 decks)

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