Ch. 10 Molecular Biology of the Gene Flashcards
Bacteriophage (Phage)
A virus that infects bacteria
Molecular Biology
The study of the molecular basis of genes and gene expression; molecular genetics.
Nucleotide
An organic monomer consisting of a 5-carbon sugar covalently bonded to a nitrogenous base and a phosphate group; building blocks of nucleic acid
Polynucleotide
A polymer made up of many nucleotides covalently bonded together
Sugar-phosphate backbone
Repeating pattern of sugar phosphate
What are pyrimidines?
Single ring of nitrogen and carbon
- Thymine and Cytosine
What are purines?
Large double ring
- Adenine and Guanine
What does RNA have that DNA doesn’t?
Uracil
Double Helix
2 DNA strands with 2 nm diameter
What are 3 major things learned?
1) How DNA is hereditary material of life
2) DNA stores information and replicates self
3) DNA controls cells by directing DNA synthesis
Virus
Infective substance, packaged genes
- 1000x smaller than bacterium
- DNA or RNA
What are the lifelike aspects of a virus?
1) Highly organized
2) Contain nucleic acids (RNA or DNA)
3) Experiences reproduction
What are non lifelike aspects of a virus?
1) Not cellular (not made of cells)
2) Cannot reproduce on its own (Inert)
Nucleic Acids
Polymer/monomers of DNA and RNA
- made of nucleotides
What are the 3 parts of a nucleotide?
1) Phosphate group
2) 5 Carbon Sugar (Deoxyribose or ribose)
3) Nitrogen Base
What is a nitrogen base?
Rings of nitrogen and carbons with various functional groups attached
What is encoded in the nucleotide sequence?
Genetic information in chromosomes
- how to make proteins
- makes each organism unique
- understand/explains life’s process
DNA Replication
Process in which genetic instructions are copied before the cell divides
What are the 3 steps of DNA Replication?
1) Two parent strands separate to serve as a template for complimentary strand
2) Free nucleotides line along template and connect to corresponding nucleotide according to base pairing
3) Enzymes link nucleotides together to form new DNA strand
Why is DNA replication biochemically complicated?
1) DNA must unravel and copy simultaneously
2) Speed! Occurs very rapidly!!
Origin of Replication
Site where proteins attach to DNA molecule and separate strands
Replication Bubble
Areas where origin of replication are; several exist to reduce time; eventually combine for daughter strands
DNA Polymerase
Enzyme that links DNA nucleotides to growing strand (proper location)
- only adding on 3’ (5’ -> 3’)
- Adds nucleotides in continuous pieces for one and in discontinuous pieces for another
- proofreads the sequence and fixes it (repairs DNA damage)
DNA Ligase
Enzyme that ties all the pieces intro one strand
- 12 altogether
What does DNA replication ensure?
Ensures all somatic cells have same genetic instructions for continuity between generations
What is the 3’ end of a DNA strand?
3’ with -OH
What is the 5’ end of DNA strand?
5’ with phosphate group
What is the connection between genotype and proteins of phenotype?
DNA specifies the synthesis of proteins.
DNA -> RNA -> Proteins
Transcription
Transfer of info from DNA to RNA
- occurs in nucleus
- uses only 1 DNA strand and hydrogen bonds