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DNA/MITOSIS/MEIOSIS
Question | Answer |
---|---|
DNA stands for | deoxyribonucleic acid |
Erwin Chargraff | observed that A always pairs with T and G always pairs with C, therefore, A & T are always found in equal amounts as are C & G |
Phoebus Levine | determined that DNA is made-up of sugars, phosphate groups, and 4 nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C) |
Rosalind Franklin | used X-ray crystallography to create images of DNA molecules |
Watson and Crick | used Chargaff’s rules and Franklin’s X-ray images to build a 3-dimensional model of a DNA molecule |
What shape is the shape of DNA? | double helix |
The sides(or handrails) of the ladder are made of | sugar and phosphates |
The rungs or steps of the ladder are made of | nitrogen bases |
What is a nucleotide? | sugar+phosphate+nitrogen base |
The four nitrogen bases are | adenine(A), thymine(T),cytosine(C) and guanine(G) |
What are the complimentary base pairs? | A-T and G-C |
What are genes? | segments or sections of DNA that give the code for a certain trait |
What is replication? | the process of copying DNA |
What is a mutation? | changes in the number, type, or order of nitrogen bases on a piece of DNA. |
What is a deletion? | when a base is left out. |
What is an insertion? | when an extra base is added. |
What is a substitution? | when one base replaces another. |
Human Genome Project | the international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings. |
How many chromosomes are in a human body cell? | 46 |
What is chromatin? | a complex mass of DNA and protein in the nucleus |
What is a chromosome? | X-shaped structures in the nucleus that contain all of the genetic information for an organism |
What is a chromatid? | one strand of a double-stranded chromosome or “half of an X” |
What are the 3 phases of the cell cycle? | Interphase, Mitosis, and Cytokinesis |
What happens during interphase? | a period of rapid growth and development. During this time, the cell is NOT DIVIDING. Cell doubles in size Cell produces more organelles Cell goes about normal cell activities Cell prepares for division – DNA is copied |
What is mitosis? | is the part of a cell’s life cycle when the nucleus divides. |
What is cytokinesis? | the part of a cell’s life cycle when the cytoplasm divides, In an animal cell, the cell membrane pinches inward between the 2 new nuclei |
What forms in plant cells at the end of mitosis? | Cell plate |
Describe what happens in prophase? | the chromatin thickens and becomes visible as chromosomes, the nuclear membrane disappears, centrioles form at the opposite ends of the cell, spindle fibers are released |
Describe what happens in metaphase? | the chromosomes line-up across the middle of the cell each centromere is attached to a spindle fiber |
Describe what happens in anaphase? | spindle fibers shorten, the double-stranded chromosomes separate to form chromatids, the separated chromatids move towards opposite ends of the cell |
Describe what happens in telophase? | the centrioles and spindle fibers disappear, Genetic material become harder to see as it reverts back to chromatin, nuclear membrane reappears cytokinesis begins |
A the end of Mitosis how many dughter cells are produced? | 2 daughter cells |
If a parent cell has 10 chromosomes, how many chromosomes do the daughter cells have? | 10 |
What is meiosis? | the type of cell division that produces sex cells |
Diploid means | the full number of chromosomes |
Haploid means | half the full number of chromosomes |
What is fertilization? | the joining of a sperm cell and an egg cell |