Download DNA Replication - Madison County Schools

DNA Replication
DNA Replication
• The process of copying/synthesizing DNA
• 3 Step process
Step 1- Unzip DNA
• DNA chains are
separated by helicase.
•
– Helicase = enzyme that
breaks the Hydrogen bond
between bases.
Step 2 - Assembly
• DNA polymerase
builds a new DNA
chain on the old DNA.
•
• One complementary
nucleotide is added at
a time.
– Base-pairing rules
apply! (G-C A-T)
Step 3 – Identical
DNA Molecules!!!
• Only 1 side of the
DNA molecules is
new!!
- ½ of the DNA is new
and ½ of the DNA is
old!
DNA REPLICATION
replication fork, helicase, nucleus, complete, DNA polymerase, old,
new, identical, hydrogen, A, C, nucleotides
DNA replication occurs in the 1___ of cells. The DNA is
replicated so that when a cell divides, each daughter cell
receives a 2___ copy of genetic material. The enzyme
3___ begins by breaking the 4___ bonds between
complementary bases (5__ with T, and 6__ with G) on
opposite strands of DNA. New 7___ are added to each
original strand by the enzyme 8___. As helicase moves
along the DNA strand, the 9__ continues to widen and
new unpaired nucleotides are added. The new
(daughter) DNA strand can be continually built as
complementary nucleotides (bases) are added by DNA
polymerase. This process builds a 10___ DNA chain
onto the 11__ DNA. The DNA is thus completely
replicated and now there are 2 genetically 12___ DNA
molecules in place of the original DNA.
DNA REPLICATION
9-replication fork, 3-helicase, 1-nucleus, 2-complete, 8-DNA
polymerase, 11-old, 10-new, 12-identical, hydrogen, 5-A, 6-C,
7-nucleotides
DNA replication occurs in the 1___ of cells. The DNA is
replicated so that when a cell divides, each daughter cell
receives a 2___ copy of genetic material. The enzyme
3___ begins by breaking the 4___ bonds between
complementary bases (5__ with T, and 6__ with G) on
opposite strands of DNA. New 7___ are added to each
original strand by the enzyme 8___. As helicase moves
along the DNA strand, the 9__ continues to widen and
new unpaired nucleotides are added. The new
(daughter) DNA strand can be continually built as
complementary nucleotides (bases) are added by DNA
polymerase. This process builds a 10___ DNA chain
onto the 11__ DNA. The DNA is thus completely
replicated and now there are 2 genetically 12___ DNA
molecules in place of the original DNA.
What happens if an error
occurs?
• Approximately only one error occurs for
every billion paired nucleotides added.
• When mistakes in DNA replication do
occur, the base sequence of a DNA
molecule is of an important gene and
disrupt an important cell function.
DNA
RNA
•
•
•
•
•
•
•
•
•
•
Double Helix
Deoxyribose sugar
Phosphate
Base
A-T C-G
Single helix
Ribose sugar
Phosphate
Base
A-U C-G
RNA Structure and Function
•
•
•
•
•
Types of RNA
Cells have three major types of RNA:
messenger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)
RNA Structure and Function
• mRNA carries the genetic “message” from
the nucleus to the cytosol.
• rRNA is the major component of
ribosomes.
• tRNA carries specific amino acids, helping
to form polypeptides.
Transcription
• During transcription, DNA acts as a
template for directing the synthesis of
RNA.
Genetic Code
• The nearly universal genetic code
identifies the specific amino acids coded
for by each three-nucleotide mRNA
codon.
Genetic Code
• Steps of Translation
– During translation, amino acids are
assembled from information encoded in
mRNA.
– As the mRNA codons move through the
ribosome, tRNAs add specific amino acids to
the growing polypeptide chain.
– The process continues until a stop codon is
reached and the newly made protein is
released.
Translation Video
https://www.youtube.com/watch?v=-K8Y0ATkkAI
Name:
1. Where are the instructions making proteins located in the body?
2. Where does a gene, that codes for an RNA molecule begin and end?
region &
region
3. What are the two processes of gene expression & where are they located?
a)
; located:
b)
; located:
4. What enzyme is used to make an RNA molecule?
5. Do introns or exons code for proteins? (Circle one)
6. What is it called when introns are removed from the RNA?
7. Where does the mRNA go to begin translation?
8. What brings the anticodons & amino acids to the RNA during translation?
9. Which codons code for start and stop? Write start and stop next to the matching codons.
AUG
UGA
11. What is the purpose of translation?
UAG
UAA