Module 1: Dna And Rna

Front 1

Anticodon

Back 1

The three bases of the mRNA codon are complementary (i.e., they base-pair) to three bases on the tRNA known as the anticodon

Front 2

Central dogma of molecular biology

Back 2

First, a portion of the DNA, a gene, is transcribed to produce a complementary strand of RNA; then the RNA is translated into protein

Front 3

Codon

Back 3

During translation the tRNA "decodes" the mRNA three bases at a time. These three bases located on mRNA are called a codon.

Front 4

Exons

Back 4

The expressed sequences from a new mRNA strand that remain in the mRNA after splicing. The exons will be the part of the mRNA translated into protein

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Gene expression

Back 5

Recruitment of RNA polymerase and subsequent production of a new RNA transcript of a gene

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Introns

Back 6

Intervening sequences in a newly made mRNA molecule that are removed by splicing before the mRNA is released into the cytoplasm for protein synthesis (translation)

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mRNA

Back 7

Messenger RNA. The mRNA is a transcript made from the DNA sequence that carries the information from the DNA in the nucleus to the cytoplasm of the cell where it can be translated into protein.

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Polypeptides

Back 8

The protein products of translation are often called polypeptides. A single polypeptide is the result of the transcription and translation of a single gene.

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promoter

Back 9

The initiation of RNA synthesis requires a specific DNA sequence at a site known as a promoter. The promoter is located just upstream of a gene and is the binding site for transcription factors that recruit the RNA polymerase

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Ribosome

Back 10

The ribosome is a complex molecular machine consisting of protein and ribosomal RNA (rRNA) that translates the mRNA to protein.

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RNA polymerase

Back 11

The primary enzyme involved in transcription that reads the DNA sequence of a gene and produces a complementary mRNA molecule

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rRNA

Back 12

Ribosomal RNA. The rRNA is part of the ribosome.

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Splicing

Back 13

The process in which portions of an mRNA sequence called introns (intervening sequences) are removed, and the remaining portions of the gene (expressed sequences, or exons) are joined together.

Front 14

Transcription bubble

Back 14

RNA polymerase separates the two DNA strands in a small portion of the DNA molecule to form a transcription bubble, thus allowing it to access the template strand and begin RNA synthesis

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Transcription factors

Back 15

Specific proteins that recognize and bind to the promoter sequence of a gene. The binding of transcription factors helps to recruit RNA polymerase to the transcription start site to begin gene expression

Front 16

Transcription start site

Back 16

The transcription start site is at the beginning (5' end) of a gene and is the location where RNA polymerase begins transcription of that gene.

Front 17

Translation

Back 17

The synthesis, or production, of protein by the ribosome using the sequence of messenger RNA (mRNA) as a template.

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tRNA

Back 18

The transfer RNA, or tRNA, are specialized molecules used by the ribosome to translate the mRNA sequence into protein. The tRNAs have an anticodon sequence that matches up to a specific codon on the mRNA. The codons correspond to a specific amino acid, which the tRNA brings to the ribosome for addition to the growing peptide chain.

Front 19

How are DNA and RNA different? How are DNA and RNA similar?

Back 19

Both DNA and RNA contain adenine (A), guanine (G) and cytosine (C).

RNA is single stranded and contains Uracil (U). DNA is double stranded and contains Thymine (T).

Front 20

What are the three types of RNA?

Back 20

messenger RNA (mRNA)

transfer RNA (tRNA)

ribosomal RNA (rRNA)

Front 21

Identify the coding strand and noncoding strand in the following image.

Back 21

Front 22

Silent mutations

Back 22

point mutations that result in no change in amino acid sequence

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Missense mutations

Back 23

point mutations that change a single base pair in a codon such that the codon now encodes a different amino acid

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Nonsense mutations

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point mutations that change a single base pair in a codon to a stop codon that terminates translation

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frameshift mutations

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Insertions or deletions of one or more base pairs (if the number of base pairs is not a multiple of 3) that disrupt the coding of a protein

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base excision repair (BER)

Back 26

DNA damage repair mechanism where a single nucleotide is replaced,

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nucleotide excision repair (NER)

Back 27

DNA damage repair mechanism where several nucleotides, usually around 30, are removed and replaced

Front 28

thymine dimer

Back 28

two thymines fuse together, caused by UV radiation

Thymine dimers are repaired by nucelotide excision repair (NER)

Front 29

What are the steps involved in excision repair? This applies to nucelotide excision repair and base excision repair.

Back 29

1. Recognize the damage

2. Remove the damage by excising part of one strand to leave a gap

3. Resynthesize the sequence using genetic information from the other strand to fill the gap

4. Ligate to restore continuity of the DNA backbone.

Front 30

How is mismatch repair similar to nucleotide excision repair? How is mismatch repair different from nucleotide excision repair?

Back 30

Mismatches do not arise from DNA damage. Rather, the wrong base has been added that ends up causing a bend in the helix. Mismatch repair follows the same steps as nucelotide excision repair. However, the base or bases that are removed during mismatch repair come from the newly synthesized strand rather than repair of parental DNA.

Front 31

homologous recombination

Back 31

Following a break in the two strands of DNA, the sequence is repaired by inserting a section of DNA that is identified as homologous. This can also occur without DNA damage to shuffle genes.

Front 32

In the organization of DNA into chromosomes, DNA is wrapped around _________ to form nucleosomes. Nucleosomes are organized further to form a _____________.

Back 32

In the organization of DNA into chromosomes, DNA is wrapped around histones to form nucleosomes. Nucleosomes are organized further to form a chromatin fiber.

Front 33

How many chromosome pairs does a human have?

Back 33

23 pairs (46 total chromosomes)

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phenotype

Back 34

observable characteristics or traits that arise from genotype

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genotype

Back 35

complete set of genes for a characteristic or trait

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homozygous genotype

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arises from two identical alleles

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heterozygous genotype

Back 37

arises from two variations of alleles

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dominant allele

Back 38

An allele that dominates or masks the presence of another allele, producing a dominant trait.

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recessive allele

Back 39

The allele, whose presence is completely masked by a dominant allele, producing a recessive trait.

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Incomplete dominance

Back 40

Produces different phenotypes based on the combination of alleles present in the heterzygotes.

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Codominance

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Occurs when the effects of both alleles appear in the heterozygote (one allele is not dominated by the other)

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sex-linked traits

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result from sex-linked inheritance where the recessive trait predominantly impacts males and a dominant trait can impact both males and females

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Epigenetics

Back 43

Study of how environmental and lifestyle factors can impact gene expression; above the genome

Front 44

Briefly explain the steps in a PCR cycle.

Back 44

1.) DNA strands are separated by heat.

2.) Primers anneal to DNA strands.

3.) Extension of newly formed DNA by DNA Polymerase.

4.) Cycle repeats.