FL Holt McDougal- Biology: Chapter 8*Study Guide – Flashcards
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What did Griffith find?
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He found a transforming principle.
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How did Avery identify DNA?
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He identified DNA as the transforming principle.
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What did Hershey and Chase confirm about DNA?
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They confirmed that DNA is the genetic material.
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What does DNA stand for?
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Deoxyribonucleic acid is what DNA stands for.
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What is a nucleotide composed of?
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A nucleotide is composed of a phosphate, a sugar and a base.
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What are the names of the nitrogen containing bases?
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The names of the nitrogen containing bases are: adenine, thymine, guanine, and cytosine.
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What are pyrimidines and what bases are considered as pyrimidines?
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Pyrimidines are single rings. Thymine and cytosine are pyrimidines.
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What are purines and what bases are considered as purines?
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Purines are double rings. Adenine and guanine are purines.
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What did Watson and Crick determine about DNA?
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They determined the 3-D structure of DNA by building models.
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What did they realize about DNA?
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They realized that DNA is a double helix.
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What is a double helix?
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A double helix is made up of a sugar-phosphate backbone on the outside and contains bases on the inside.
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Who did Watson and Crick build their discovery from?
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They built their discovery from Rosalind Franklin and Edwin Chargaff.
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What are Chargaff's rules?
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His rules are that A=T and C=G.
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How is the backbone connected?
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The backbone is connected by covalent bonds.
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How are the bases connected?
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The bases are connected by hydrogen bonds.
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What does DNA replication do?
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DNA replication copies the genetic information of a cell.
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When during the cell cycle is DNA replicated?
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DNA is replicated during the S (synthesis) phase of the cell cycle.
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What is the process of DNA replication?
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1. Enzymes unzip the double helix and this forms 2 template strands. 2. Free-floating nucleotides form hydrogen bonds with the template strand. 3. DNA polymerase enzymes bond the nucleotides together to form the double helix and they correct errors.
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Why is DNA replication semiconservative?
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DNA is semiconservative because there is one original strand and a new strand.
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What does RNA stand for?
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RNA stands for ribonucleic acid.
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What does transcription do?
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Transcription converts a gene into a single-stranded RNA molecule.
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What does the central dogma state?
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It states that information flows in 1 direction from DNA to RNA to proteins.
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The central dogma includes what 3 processes?
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1. Replication 2. Transcription 3. Translation
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What are the major differences between DNA and RNA?
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1. DNA has a deoxyribose sugar. RNA has a ribose sugar. 2. DNA has thymine. RNA has uracil instead of thymine. 3. DNA is double-stranded. RNA is single-stranded.
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What are the steps of transcription?
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1. Transcription copies DNA to make a strand of RNA. 2. Transcription is catalyzed by RNA polymerase. 3. RNA polymerase and other proteins form a transcription complex. 4. The transcription complex recognizes the start of a gene and unwinds a segment of it. 5. Nucleotides pair with one strand of DNA. 6. RNA polymerase bonds the nucleotides together. 7. The DNA helix winds again as the gene is transcribed. 8. The RNA strand detaches once the gene is transcribed.
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What types of RNA does transcription make and what are their functions?
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1. Messenger RNA (mRNA) carries the message that will be translated to form a protein. 2. Ribosomal RNA (rRNA) forms part of the ribosomes where proteins are made. 3. Transfer RNA (tRNA) brings amino acids from the cytoplasm to the ribosome.
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How is transcription similar to replication?
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Transcription and replication both have complex enzymes and complementary base pairing.
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How are transcription and replication different from each other.
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Both of their end results are different. Replication copies all the DNA. Transcription copies a gene. Replication makes 1 copy. Transcription can make many copies.
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What does translation do?
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Translation converts an mRNA message into a polypeptide, or protein.
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What is a codon?
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A codon is a sequence of 3 nucleotides that codes for an amino acid.
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How many stop codons are there and what does the start codon code for?
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There are 3 stop codons and the start codon codes for (AUG) or methianine.
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What is an anticodon and what is it carried by?
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An anticodon is a set of 3 nucleotides that is complementary to an mRNA codon. Anticodons are carried by tRNA.
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How many subunits do ribosomes consist of and what are their functions?
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There are 2 subunits. The large subunit has 3 binding sites. The small subunit binds to mRNA.
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What are the binding sites called and what do they stand for?
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The binding sites are called: EPA or APE. A (Amino acid) P (Protein) E (Exit)
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What are the steps of translation?
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1. The start codon enters the P stage. 2. The start codon enters the E stage and gives their amino acid to the amino acid entering the A stage. 3. The start codon exits. 4. If a stop codon enters the A stage, the ribosome releases the protein and diassembles.
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What does gene expression do?
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Gene expression carefully regulates both prokaryotic and eukaryotic cells.
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What do prokaryotic cells do to the genes?
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Prokaryotic cells turn genes on and off by controlling transcription.
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What is a promoter?
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A promoter is a DNA segment that allows a gene to be transcribed.
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What is an operator?
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An operator is a part of DNA that turns a gene "on" or "off."
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What is an operon?
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An operon includes a promoter, an operator, and 1 or more structural genes that code for all the proteins needed to do a job.
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True or False? Operons are most common in prokaryotic cells.
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True.
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Describe the lac operon.
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The lac operon was 1 of the first examples for enzymes of gene regulation to be discovered. The lac operon has 3 genes that code for enzymes that break down lactose.
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What does a lac operon act like and why?
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A lac operon acts like a switch. The lac operon is "off" when lactose is not present. The lac operon is "on" when lactose is present.
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Tell how eukaryotes regulate gene expression.
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Most eukaryotes have a TATA box promoter. Enhancers speed up the rate of transcription. Silencers slow down the rate of transcription.
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What type of process is an important part of gene regulation in a eukaryote?
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RNA processing is an important part of gene regulation in a eukaryote.
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What are 3 steps of mRNA?
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1. Introns are removed and exons are spliced together. 2. A cap is added. 3. A tail is added.
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What are the 2 types of mutations in DNA and describe both.
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A point mutation substitutes 1 nucleotide for another. A frameshift mutation inserts or deletes a nucleotide in the DNA sequence.
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True or False? Chromosomal mutations don't affect any genes.
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False.
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What may a mutation produce?
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A mutation may cause a premature stop codon. A mutation may change protein shape or the active site. A mutation may change gene regulation.
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Why don't some gene mutations affect phenotype?
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A mutation may be silent, a mutation may occur in a noncoding region, mutations in body cells do not affect offspring and mutations in sex cells can be harmful or beneficial to offspring.
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List the factors of how mutations can happen.
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1. Replication errors can cause mutations. 2. Mutagens, such as UV rays and chemicals, can cause mutations. 3. Some cancer drugs use mutagenic properties to kill cancer cells.
