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DNA and RNA
Chapter 12-1
| Question | Answer |
|---|---|
| What are the four bases? | 1. Adenine 2. Thymine 3. Cytosine 4. Guanine |
| What does DNA do? | It keeps code and contains instructions for the organism |
| What is sugar in DNA? | Deoxyribose |
| What is the backbone of DNA made of? | Sugar and phosphates |
| Purines | 2 rings |
| Pyrimidines | 1 ring |
| Chargaff's rules | Adenine alsways bonds with thymine and guanine always bonds with cytosine. |
| Is DNA a double helix? | Yes |
| What bonds between nitrogen bases and holds the two strgands together? | Hydrogen |
| Describe the chromosome structure in prokaryotes | -DNA is circular -DNA is single -Found in cytoplasm |
| Describe the chromosome structure of eukaryotes | -DNA is in multiple -Chromome bundles -Found in necleus |
| What are eukaryotic chromosomes made of? | DNA and proteins called histones |
| Nucleosome | DNA and histone proteins formed in a bead-like structure |
| Base-pairing | Adenine & thymine pair together and cytosine & guanine pair up |
| Replication forks | Sites where strand separation and replication occur |
| 3 replication steps | 1. Enzymes "unzip" molecule by breaking down hydrogen bonds 2. DNA polymerase joins nucleotides using original strand as template and spell checks for errors 3. Copying happens in opposite directions along the two strands & in mulitiple places at once |
| RNA | -Also made of nucleotides -Sugar is ribose instead of deoxyribose -Single stranded -Contains uracil instead of thymine |
| 3 RNA help | 1.Ribosomal - combines with proteins to form ribosomes 2. Transfer - matches m-RNA codon to add correct amion acids during protein synthesis 3. Messenger -carries code from DNA to ribosomes |
| RNA polymerase | An enzyme that is responsible for creating RNA from a DNA template |
| How does RNA polymerase know where a gene starts and stops? | -(Promoters) enzyme binds to places with certain DNA sequences -Promoters tell RNA polymerase where to start -Signals at the end of the gene code cause transcript to stop |
| Why spend energy making a large RNA and then throw parts away? | The same gene can be used in different ways |
| Where does transcription and processing take place? | In the nucleus |
| Where does translation take place? | On ribosomes in cytoplasm |
| Codons | Sequence of three nucleotides that together form a unit of genetic code |
| How many possible codons are there? | 64 |
| How much amino acid does tRNA carry? | Only 1 kind |
| Replication | RNA - DNA |
| Transcription | DNA - RNA |
| Translation | RNA - Protein |
| Central dogma of biology | Basic framework for how genetic information flows (DNA - RNA - Protein) |
| Mutations | Changes in the genetic material |
| When do mutations happen? | -Mistakes in copping their own DNA -Radiation -Chemicals in the environment |
| Gene mutations | Mutations that produce changes in a single gene |
| Chromosomal mutations | Mutations that produce changes in whole chromosomes |
| Point mutation | Mutations involving one or a few nucleotides |
| What are the 3 types of point mutation? | 1. Substitutions 2. Deletions 3. Insertions |
| Substitution | Changes one base for another |
| Deletion | Piece of DNA code for one gene is lost |
| Insertion | Piece of DNA is copied too many times |
| Frame shift mutations | Change multiple bases in code |
| Are mutations at the beginging of the gene damage more or less of the code? | More of the code |
| Chromosomal mutations | Mutations invlolving changes in the number or structure of whole chromosomes |
| What are the types of chromosomal mutations? | -Deletions -Duplications -Inversions -Translocations |
| Duplication | Piece of DNA is copied too many times |
| Inversion | Segment flips and reads |
| Translocation | Segment breaks off and joins a different non-homologous chromosome |
| Facts about mutations | -Most mutations are neutral, they have little or no effect on gene function -Mutations that cause defective proteins are usually harmful -Harmful mutations are associated with many genetic disorders and can cause cancer |
| What are mutations a source of? | Genetic variablility and beneficial |
| How are mutiations helpful? | They provide variation in population for natural selection to act upon |
| Polyploidy | Condition in which an organism has extra sets of chromosomes |
| Regulatory sites | Control whether a gene is ON of OFF |
| Operon | Group of genes that operate together |
| Repressor molecule | It sits on a regulatory site next to the promoter called the operator |
| TATA box | DNA sequence that indicates where a genetic sequence can be read and decoded |
| How do cells differentiate? | By turning different genes on and off |
| Hox genes | -These genes control the organization of the developing embryo -Tell parts where to grow / when |
| How do you know when organisms share a common ancestor? | They similarites betwwen Hox gene sequences and ability of these genes to trade places, and still function in different species |
Created by:
kieren1
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