Class Work: Division and Multiplication

1. What is DNA?
DNA - the Blueprint of Life
*Every living organism contains within itself the information it needs to build a new organism.
2. What are the 4 bases?
In DNA they are A, T, C and G; where A stands for adenine, T for thymine, C for cytosine and finally G for guanine.
3. What 2 peices of information did the scientists need to solve the elusive structure of DNA?
Phosphate backbone, double helix.
4. What are the specific base pairs?
(adenine,thynine) (guanine,cytosine)
5. How does the pairing rule effect the shape and structure of DNA?
A and T makes a 2H and G and C makes 3H bond, which restricts the structure of the DNA block during its copying process.
6. What does the DNA do during cell division?
DNA unwinds so it can be copied and the copies transferred to new cells. DNA also unwinds so that its instructions can be used to make proteins and for other biological processes.
7. How many base pairs does E. Coli have? How long does it take to replicate? How is the DNA packaged in the cell?
4, 639, 221
40 minutes
It is packaged in a tight coil in the nucleus of a cell
8. How many base pairs does Human DNA have? How long does it take to replicate? How is the DNA packaged in the cell?
3 billion + base pairs
12 – 24 hours
In the nucleus

1. What is RNA? How different is it from DNA?
RNA - a Blueprint Copy
Ribonucleic acid is a blueprint copy of DNA. RNA is only made of a single strand. Furthermore, the base T, thymine, is replaced by U, uracil in RNA.
2. How are the RNA messages formed?
RNA messages are formed by the grouping together of 3 of the letters to create a triplet or codon. The codons line up and form a chain of codes that create a message.
3. How are the RNA messages interpreted?
Ribosomes read the messages and then attach the amino acids together to make up a protein.

1. Describe cell cycle.
Gap 1 phase: cell growth begins
Synthesis phase: chromosomes duplicate and divide; cell growth continues
Gap 2 phase: cell reaches proper size
Mitosis phase: cell division
*chromosomes are stored in the cell nucleus
*CDK and cyclin are the key molecules that control and coordinate cell division
2. What is nuclear division?
Nuclear division is the division of the nucleus and genetic information into more than one cell from a parent cell, usually through mitosis or meiosis.
3. What is interphase?
When the cell or nucleus is not in mitosis.
4. Cytokinesis?
The stage in meiosis in which the cytoplasm of the cell is divided after the nuclear division.
5. Homologous chromosomes?
Pair of chromosomes that have the same genetic sequencing because they come from the same parent cell.
6. Phases of mitosis.
Prophase
Metaphase
Anaphase
Telophase
Interphase
7. Phases of meiosis and how it is different from mitosis.
Early prophase
Late prophase
Metaphase
Anaphase
Telophase
Second Telophase
*Meiosis is different from mitosis because the cell goes through 2 divisions instead of just one and results in 4 daughter cells instead of only 2.
*Cells that go through mitosis are called diploid cells because it has 2 complete sets of chromosomes. Cells that go through meiosis only have a single set of chromosomes that is completed when the female and male gamete are united.
8. Describe the process and purpose of crossing over.
Crossing over occurs only when the sperm and egg chromosomes pair up and swap genetic information, reducing the number of chromosomes to a complete set. It is important because it allows the number of chromosomes the normal number and also allows the genetic information to remain present in the cell.