DNA
About this set
Created by:
garrieli000 on November 20, 2011
Log in to favorite or report as inappropriate.
Order by
38 terms
Terms | Definitions |
|---|---|
 DNA/RNA | Deoxyribonucleic Acid/Ribonucleic Acid |
| DNA consists of what? | Nucleotides: each nucleotide has a deoxyribose, a phosphate group and a nitrogenous base. |
| Nucleotides... | differ in their nitrogenous bases: Thymine (T), Cytosine (C), Adenine (A) and Guanine (G). |
| Purines | larger molecules-- Adenine and Guanine |
| Pyrmidines | smaller molecules-- Thymine and Cytosine |
| Sugar-phosphate backbone | Nucleotides are joined by the sugar-phosphate backbone which alternates deoxyribose and phosphate bonded by a covalent bond. |
| Double Helix | a rope like ladder twisted into a spiral: James Watson and Francis Crick determined that DNA took the form of a double helix. |
| DNA base pairs | Adenine pairs with Thymine and Cytosine pairs with Guanine. |
| Anti-parallel | the sugar-phosphate backbones of each strand run in opposite directions: one strand reads 5' to 3' and the other reads 3' to 5'. |
| Hydrogen bonds | hold two nitrogenous bases together: the bonds are weak so they can be easily broken and put back together. The double helix makes the bonds harder to break. |
| DNA replication | produces a complete copy of the DNA from one parent cell to two daughter cells. Watson and Crick's model suggests DNA replicates by a template mechanism. |
| Process of replication | 1. Helicase attaches to a "point of orgin" on the DNA 2. Helicase unwinds and unzips two strands from eachother- replications "bubbles" are formed 3. DNA polymerase attaches to each half of the DNA 4. DNA polymerase attaches "free floating" nucleotides to each strand of DNA. |
| DNA replication in eukaryotes | begin at a specific "point of orgin" on the double helix (there are many working together) the polymerase proceed in opposite directions. |
| Cell divison | reproduction of a cell: first the chromosomes are duplicated- each daughter cell gets one set of chromosomes. |
| Importance of cell divison | replaces damaged or lost cells; permits growth; allows for reproduction |
| Asexual reproduction | the one parent and two daughters have identical genes through mitosis. Mitosis is used for asexual reproduction and growth and maintenance of mutlicellular organisms. |
| Sexual reproduction | requires fertilization of an egg by sperm, using meiosis. Sexually reproducing organisms use meiosis for reproduction and mitosis for growth and development. |
| Cell Cycle and Mitosis | most genes are located on chromosomes in the nucleus; a few genes are found in the mitochondria or chloroplasts. |
| Genes | the recipe for a protein |
| Chromosomes | are made of chromatin, a combination of DNA and protein molecules; they're not visible until cell division. |
| Histones/Nucleosomes | the proteins used to package DNA in eukaryotes; nucleosomes consist of DNA wound around histene molecules. |
| Sister chromatids | before a cell divides it duplicates all of its chromosomes resulting in 2 coplies: the sister chromatids are joined together at a narrow "waist" with a protein called a centromere. |
| Once separated... | each chromatid is considered a chomosome and is identical to the original chromosome. |
| Humans have... | 46 total chromosomes: sex cells have 23 chromosomes |
| Cell cycle | the orderly sequence of events that extend from the time a cell is fromed from to divison to when it divides into 2. |
| Two distinct phases | interphase and the mitotic phase |
| Interphase | 90% of life/ G1: normal functions and grows S-phase: DNA replication G2: everything is doubled |
| Two phases of the mitotic phase | Mitosis: the nucleus and its contents divide into two daughter nuclei Cytokinesis: cytoplasm is divided in 2 |
| Mitosis | the mitotic spindle guides the separation of 2 sets of daughter chromosomes; spindle microtubules grow from 2 centrosomes. |
| Mitosis consists of 4 distinct phases: | Prophase, Metaphase, Anaphase, Telophase |
| Cytokinesis | occurs during telophase, divides the cytoplasm, is different in plants and animals: animals- cleavage furrow, plants- cell plate |
| Cell control system | consists of specialized proteins which send "stop" and "go-ahead" signals at certain keys points in the cycle. |
| What is caner? | a disease of the cell cycle; cells that don't respond normally to the control system; can form tumors |
| Tumors | abnormally growing masses of body cells |
| Metastasis | the spread of cancer cells beyond their original site of orgin |
| Malignant tumors | can spread to other parts of the body and interrupt normal body functions. A person with a malignant tumor is said to have cancer. |
| Radiation therapy | damages DNA and disrupts cell division. |
| Chemotherapy | uses drugs that disrupt cell division. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.