Name_____________________________________________ Date______________Period__________
Do I remember DNA? - ANSWER KEY
1. DNA stands for:
Deoxyribonucleic acid
2. What is the shape of DNA?
Double helix
3. Who established the structure/model of DNA?
Watson and Crick (with help from Rosalind Franklin)
4. Adenine always pairs with thymine
5. The sides of the DNA ladder are deoxyribose and phosphate. The rungs/steps are
made up of nitrogen bases.
6. Guanine always pairs with cytosine.
7. What is the complementary sequence in DNA?
C
A
T
T A G
G
T
A
A
T C
8. The two sides of DNA are held together by hydrogen bonds.
9. DNA is composed of repeating subunits called nucleotides.
10. What are the 4 bases that make up the rungs of the DNA ladder?
Adenine, Thymine, Cytosine, and Guanine
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11. One group of 3 bases codes for one amino acid.
12. During protein synthesis, the cell uses information from a gene on a chromosome to
produce a specific protein.
13. What determines your genetic code?
The sequence (order) of the nitrogen bases
14. During protein synthesis, mRNA makes a copy of DNA in the nucleus. Why does this
happen?
DNA cannot leave the nucleus. The information in the DNA needs to get to the
ribosome in the cytoplasm to produce the proteins.
15. Then mRNA takes the coded message to the cytoplasm where the ribosomes are
located. There the code is translated and amino acids are placed (and join together)
producing a protein/trait.
16. What is a mutation?
A mutation is a change in the sequence of bases.
18. How can mutations affect protein synthesis in cells?
A mutation can change what amino acid is added to the protein molecule
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19. Are all mutations harmful? Explain.
Not all mutations are harmful. They are only harmful if they affect the organism’s ability
to reproduce and survive.
20. Sutton, working with grasshoppers, hypothesized that chromosomes were the key
to understanding how offspring have similar characteristics to their parents (called the
Chromosome Theory)
21. Meiosis is the type of cell division that produces sex cells.
22. Sex cells include sperm and eggs.
23. Sex cells have half the number of chromosomes in comparison to body cells.
24. How many chromosomes do human body cells have? How many chromosomes are
the in sperm and egg cells?
Human body cells have 46 chromosomes. Sperm and egg cells have half that number,
23 chromosomes.
25. Why is it important that sex cells have half?
When the sperm and egg combine, the resulting embryo needs to have 46
chromosomes.