Download Molecular Genetics - The Bronx High School of Science

Molecular Genetics
DNA
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Define the term DNA
Deoxyribonucleic acid
Why is DNA important?
Stores our genetic material
Describe the structure of DNA
Double helix, 4 types of nucleotides (ATCG)
Describe the structure of a nucleotide
Phosphate group, deoxyribose, nitrogenous waste
How do the bases pair?
A – T, C - G
Structure of DNA
DNA continued
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How are the two strand bound together?
Hydrogen bonds between bases
How does DNA store our genetic material?
As genes
How do genes differ?
Sequence of nucleotide bases
Replication
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Why do we want DNA to replicate?
For cell division (growth)
How does replication begin?
Breaking of Hydrogen bonds
How are those bonds broken?
Helicase
How are the two new strands synthesized?
DNA polymerase
How do the two strands compare to the original strand?
Exactly the same
Replication continued
• Define semi-conservative replication
• Each original strand acts as a template for
the new strands to be formed
• Each new strand is a combination of one
original and one newly synthesized strand
• Write the complementary strand:
ATTTGCCACGGGAATACG
• Diagram the replication of this strand of
DNA
Replication of DNA
DNA replication
Protein Synthesis
• Where are proteins made in a cell?
• Ribosome
• Where do the instructions for the protein come
from?
• DNA/Gene
• How does the gene get to the ribosome?
• mRNA (messenger RNA)
• What process creates mRNA?
• Transcription
Transcription
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How is the gene exposed to make a RNA copy?
Break hydrogen bonds
How is mRNA synthesized?
RNA polymerase
Where does transcription take place?
Nucleus
Where does mRNA go?
Ribosome
Transcription
Translation
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How does the ribosome use the mRNA?
Guide to build the protein
How do amino acids get to the ribosome?
tRNA – transfer RNA
How do the tRNAs differ?
Each carries a specific amino acid
Describe the structure of tRNA
Anticodon corresponds to a specific amino acid
Translation continued
• How does the ribosome use the mRNA
and tRNA to synthesize proteins
• Ribosome allows tRNA to bind with codon
(triplet of bases on mRNA) if bases are
complementary
• Why is it beneficial that the mRNA can be
re-used?
Translation
Genetic Engineering
• Define selective breeding
• Having organisms of the same species
breed to get offspring with desirable traits
• Drawbacks to selective breeding
• No guarantee the traits wanted will be
present in the offspring
Genetic Engineering II
• Define Hybridization
• Breed two closely related organisms to get
desired traits
• Example: liger, horse + donkey = mule;
husky and wolf = big dog!!
• Define Inbreeding
• What are some problems with inbreeding?
• Non-desirable traits (recessive usually) are
expressed more often in the offspring
Genetic Engineering III
• Define transformation in terms of genetic
• Define recombinant DNA
• DNA of two or more species that are
combined together (bacterial plasmid with
human gene; glow in the dark rabbit, etc.)
• How can we produce recombinant DNA?
• Describe the function of restriction
enzymes in creating recombinant DNA
Transformation
Genetic Engineering IV
• Define the term clone
• Describe a procedure to make a clone
• Genetically how would clones from one donor
compare
• Would they all look the same? Explain
• No, different genes may be activated causing
the clone to look different
• Can you breed clones from one donor?
• No they are all the same sex
Cloning Techniques