1. DNA Replication
Biology II

2. Bell Ringer Questions/Exit Questions
Explain “Diploid”
Explain “Haploid”
What is the difference between Somatic vs. Sex Cells?
DNA is made up of what?

4. DNA Replication
Before a cell divides, it duplicates its DNA in a process called replication
Replication=DNA copies itself exactly
Occurs with in the nucleus
Any mistakes in copying=mutation

5. DNA Replication
1. Complementary Base Pairing: makes replication possible
makes replication possible
C - G
A - T

6. DNA Replication
One side of the DNA molecule is a template for making the other (strand)
New Strand
Original strand
Nitrogen Bases
Replication Fork
Growth
Growth
DNA Polymerase

7. DNA Replication
DNA replication is carried out by enzymes that “unzip” the DNA called helicase
Hydrogen bonds between base pairs are broken and the two strands of DNA unwind

8. DNA Replication
The principal enzyme involved in DNA replication is DNA polymerase
Joins individual nucleotides to produce a DNA molecule
Proofreads each strand

9. Semi-conservative Replication
Each new DNA molecule contains one old strand and one new strand

10. In prokaryotic cells, DNA is found in the cytoplasm. nucleus.
12–2
In prokaryotic cells, DNA is found in the
cytoplasm.
nucleus.
ribosome.
cell membrane.
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11. The first step in DNA replication is producing two new strands.
12–2
The first step in DNA replication is
producing two new strands.
separating the strands.
producing DNA polymerase.
correctly pairing bases.
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12. 12–2
A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand?
GCGAATTCG
CGCTTAAGC
TATCCGGAT
GATGGCCAG
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13. regulate the time copying occurs in the cell cycle.
12–2
In addition to carrying out the replication of DNA, the enzyme DNA polymerase also functions to
unzip the DNA molecule.
regulate the time copying occurs in the cell cycle.
“proofread” the new copies to minimize the number of mistakes.
wrap the new strands onto histone proteins.
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14. 12–2
The structure that may play a role in regulating how genes are “read” to make a protein is the
coil.
histone.
nucleosome.
chromatin.
Copyright Pearson Prentice Hall

15. RNA and Protein Synthesis

16. RNA Structure and Function
Genes are coded DNA instructions that control the production of proteins.
Genetic messages can be decoded by copying part of the nucleotide sequence from DNA to RNA
RNA contains coded information for making proteins

17. DNA vs. RNA Differences:
The sugar in RNA is ribose instead of deoxyribose
RNA is single stranded
RNA contains uracil (U) in place of Thymine (T)

18. Structure of RNA Phosphate Group Ribose sugar
Nitrogen Containing Bases
Cytosine (C)
URACIL (Not Thymine) (U)
Adenine (A)
Guanine (G)

19. 3 Types of RNA
There are 3 types of RNA, each with a specific function:
Messenger RNA (mRNA): A straight RNA molecule that carries a complimentary copy of a gene.
The complementary copy of a gene (found on DNA) is called the genetic code (found on the mRNA)
The genetic code is read 3 bases at a time (AUG, GGA, etc) which are called codons
**Brings instructions indicating which amino acids will be needed and in which order they will be bonded together.

20. 3 Types of RNA
Transfer RNA (tRNA): A folded RNA molecule that is t-shaped
At the top of the tRNA molecule is the site where amino acids (protein monomers) attach.
At the bottom of the tRNA molecule is the site where the genetic code is read
**Brings amino acids to the ribosome!

21. 3 Types of RNA Ribosomal RNA (rRNA): a folded globular shaped molecule
***Site of Protein Synthesis

22. A G C T T C G C A G G C C A T