Download Slide 1 - Piscataway High School

Chromosomes
Chromosomes
Prokaryotes (bacteria):
One
In cytoplasm
Circular
Eukaryotes:
Many
In Nucleus
Linear
-Chromosomes are very long.
Bacteria with chromosome released.
In eukaryotes, DNA in chromosomes is wrapped
around histone proteins to make bundles called
nucleosomes.
histones
nucleosome
DNA Replication
-process of making a copy of the genome
Each strand acts as a template to make a new one.
Both strands are copied at the same time, but in the opposite direction.
DNA Replication
-process of making a copy of the genome
Prokaryotes
Eukaryotes
Cytoplasm
Nucleus
Replication Close
Hydrogen bonds
broken
Up
DNA Replication Product:
-2 double stranded chromosomes
-half original and half new
semi-conservative
What enzyme does DNA replication?
DNA Polymerase
DNA polymerase
also
edits its mistakes
(proofreads)
DNA polymerase will
fix this
What is the function of chromosomes?
-control all cell activities
-contain genes
Genes
-DNA base sequences
-instructions for controlling
the production of proteins
How do we get from DNA to protein?
-we need to make a disposable copy of the gene
Transcription
DNA
RNA
RNA
-Made of nucleotides
-Ribose not deoxyribose
-U, C, G, A not T, C, G, A
-Single strand not double strand
RNA
-ribose
-U, C, G,A
-single strand
-short
-disposable
DNA Versus RNA
DNA
RNA
Building blocks
nucleotides
nucleotides
Sugar
deoxyribose
ribose
Bases
T, G, C, A
U, G, C, A
Single or Double
Stranded?
Long or Short
Double
Single
Long
Short
Purpose
Permanent genome
Disposable copy of a
gene
Transcription
-DNA strands separate
-RNA polymerase binds to DNA
-one strand of DNA acts as a template to make an RNA copy of the gene
Gene
What’s next for the RNA?
Prokaryotes
Eukaryotes
RNA is processed and moved first
-introns are spliced out
-mRNA is moved to the cytoplasm
Three Types of RNA
mRNA – template for making protein
rRNA – part of the structure of ribosomes
tRNA – small RNA used by ribosomes
rRNA -