Grade 7 Science Study Guide –DNA
Test date: Wednesday, May 16th
Double helix: 2 spirals wound around each other
Rosalind Franklin: took an x-ray photo of DNA
James Watson and Francis Crick: discovered the double helix structure
and made the first model
Genes: stretch of DNA that codes for a inherited trait
Replication: process by which DNA copies itself
-
this happens when chromosomes copy themselves before
mitosis and meiosis
Steps of replication:
1. the double helix of DNA unzips by means of special enzyme
2. each original strand grows a new strand of DNA
3. the old strand becomes the pattern for the new strand of
DNA
Chargaff’s rule: in DNA, the amount of A = the amount of T the amount of C= the amount of G
DNA: the blueprint of life
Facts about DNA:
1. DNA never leaves the nucleus
2. DNA is the master copy of the directions a cell needs to live
3. DNA is a type of nucleic acid
4. DNA make up chromosomes and genes
5. DNA is a deoxyribonucleic acid
6. DNA has 2 strands
7. DNA’s job: to store genetic information
8. DNA is located in the nucleus of the cell
9. Frank Griffith discovered DNA in 1928
4 types of nitrogen bases of DNA:
1. Adenine
2. Guanine
3. cytosine
4. thymine
Heredity: passing on of characteristics from parents to offspring
RNA: carries the codes for making proteins from the nucleus to the
ribosomes in the cytoplasm
Facts about RNA:
1. RNA is a copy of DNA that goes out into cytoplasm to tell the cell
what to do in order to stay alive
2. RNA is a ribonucleic acid
3. you can always make more RNA
4. RNA has one strand
5. RNA’s job: to go into cytoplasm to make proteins
4 types of nitrogen bases of RNA:
1. uracil
2. adenine
3. guanine
4. cytosine
Inherited traits:
1. height
2. weight
3. ethnic background
4. hair
5. personality
6. freckles
7. eye size
Double helix