DNA, Protein Synthesis, Mutations, Gene Expression (87-120)
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42 terms
Terms | Definitions |
|---|---|
 What is a nucleic acid? | Polymer of nucleotides |
| What is the function of DNA? | To code for the production of proteins. |
| What is Chargaff's Rule? | Proportions of A&T and G&C are the same |
| Describe the result of DNA replication. | Semi-conservative replication in which half of the new strands are parental and the other half daughter strands |
| What structures are used in DNA replication? How are they used? | -Helicase unzips parental double helix -DNA polymerase performs base pairings -Ligase links Okazaki fragments (lagging strand) -Primase initiates replication |
| What are the differences between DNA and RNA? | -DNA uses deoxyribose, RNA uses ribose. -DNA bases are ATCG, RNA bases are AUCG -DNA is double stranded, RNA is single stranded |
| Name the three types of RNA and their function in protein synthesis | -rRNA is a protein that makes up ribosomes -tRNA transports amino acids to ribosomes -mRNA codes for the order of amino acids |
| What are the two parts of protein synthesis? What process do they complete? Where do they take place? | Transcription: Transcribes DNA sequence into mRNA (which can pass through nuclear membrane), occurs in nucleus Translation: Translates mRNA sequence to a sequence of amino acids in the ribosomes |
| What is on tRNA? | Amino acid, anticodon |
| When does transcription begin? | When RNA polymerase binds to the promoter of a gene |
| What is a terminator sequence in transcription? | A genetic sequence that marks the end of a gene or operon |
| When does translation begin? | After the mRNA arrives at the ribosomes or transcription is finished |
| What is terminator sequence in translation? | A codon in mRNA that instructs the ribosome to detach itself from the mRNA (UAA, UAG, UGA) |
| What is the effect of a frame-shift mutation? Name two types. | Causes every codon proceeding mutation to change. -Insertion: nucleotide is added -Deletion: nucleotide is removed |
| What are the effects of point mutations? | -Silent mutation: codon is changed to a codon that codes for the same amino acid -Missense mutation: a single amino acid is changed -Nonsense mutation: premature termination (codon changes to stop codon) |
| How many nucleotides does it take to code for an amino acid? How many codons? | 3 nucleotides: 1 codon: 1 amino acid |
| What occurs during RNA splicing in eukaryotes? | Introns are removed and exons are strung together. |
| Define: operator | Acts as an on/off switch, determines whether or not RNA polymerase can attach to promoter by presence or absence of repressor |
| Define: regulatory gene | Codes for production of constant amount of operon repressors so that they are available when needed |
| Define: repressor | Attaches to operator and inhibits RNA polymerase from attaching |
| Define: promoter | Where RNA polymerase attaches |
| Define: activator | Attaches to RNA polymerase when the gene folds, initiating transcription |
| When is the lac operon turned on/off? What does it produce? | In the presence of lactose, the lac operon is turned on and produces lactase. |
| When is the trp operon turned on/off? What does it produce? | In the absence of tryptophan, the trp operon is turned on and produces more tryptophan |
| Define: exon | Coding sequences of DNA |
| Define: intron | Non-coding, intervening sequences of DNA |
| Explain the process of RNA splicing, where and when does it occur? | RNA splicing strings together exons and removes introns in the nucleus, occurs after transcription but before the mRNA enters cytoplasm |
| What is alternative RNA splicing, how does it create two different proteins from the same DNA template in the nucleus? | Different exons from the RNA transcript are strung together to code for different proteins: different exons --> different mRNA --> different protein |
| What would happen if a cell would enter mitosis before S phase? | Since S phase duplicates DNA, if mitosis occurred before S phase, the daughter cells would only have half of the genetic information |
| What would happen if a cell would enter mitosis before G2 phase? | Since G2 phase produces the necessary organelles needed for mitosis to occur, without it, mitosis would go horribly wrong and nondisjunction would occur (no centrioles, spindle fibers, etc.) |
| What is a diploid cell? | A cell with two copies of genetic information/chromosomes |
| What is a haploid cell? | A cell with only one copy of genetic information/chromosomes |
| What occurs during G1 of the cell cycle? | Cell grows |
| What occurs during S phase of the cell cycle? | The DNA (chromosomes) in the cell duplicate |
| What occurs during G2 phase of the cell cycle? | The cell grows and prepares for mitosis, making necessary organelles for mitosis |
| What occurs during mitosis/cytokinesis of the cell cycle? | Parental cell is split into two identical daughter cells (cytokinesis cleaves the connection between the two cells) |
| Why do our cells look different and function differently? | Different cells are specialized to perform different functions |
| What is the relationship between a chromosome, chromatids, and homologous chromosomes? | Chromatids are the two identical parts of a duplicated chromosome. Homologous chromosomes are pairs of identical chromosomes. |
| What is the difference between mitosis and meiosis? | -Mitosis produces 2 haploid daughter cells -Meiosis produces 4 diploid daughter cells |
| What is similar between Meiosis II and mitosis? | In anaphase of both Meiosis II and Mitosis, the sister chromatids are pulled to the poles, while in Meiosis I, homologous chromosomes are pulled apart |
| Describe the function of the spindle fibers during cell division. | Spindle fibers pull apart either homologous chromosomes (meiosis I) or sister chromatids (meiosis II, mitosis) to the poles of the nucleus |
| What is non-disjunction? Why can it be detrimental to a cell? | Non-disjunction is the absence of a separation of either homologous chromosomes or sister chromatids (during either mitosis or meiosis) |
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