Chapter 26 Flashcards
What is a linkage group? How many linkage groups do humans have?
All of the linked genes on the same chromosome
23 linkage groups
What is multiple-gene, or polygenic, inheritance?
When two or more independent genes affect one characteristic
What are the four kinds of nitrogenous bases in DNA? Who bond with who?
Adenine - Thymine
Guanine - Cytosine
What type of compound are adenine and guanine?
Purine
What type of compound are cytosine and thymine?
Pyrimidines
What is the composition of a DNA molecule?
DNA is made up of:
A 5 carbon sugar deoxyribose
A phosphate group
A nitrogen base (A,T,C,G)
What holds the base pairs that form on each rung of the DNA molecule together?
Weak hydrogen bonds
Explain DNA replication in terms of leading and lagging strands
First, an enzyme breaks the weak hydrogen bond that holds the nitrogenous base pairs together then one side (leading strand) grows in 5’ to 3’ direction continuously and parallel
And the other strand (lagging strand) grows 5’ to 3’ too but it is anti parallel so it doesn’t grow continuously
What is one gene-one polypeptide hypothesis?
States that each gene directs the synthesis of a particular polypeptide chain
What is the difference between DNA and RNA when it comes to structure?
RNA has 5 carbon sugar ribose and uses Uracil instead of Thymine
Only single strand of nucleotides
What is Messenger RNA or mRNA?
It is the first step in directing protein synthesis and it is when the DNA code is copied for a polypeptide.
The DNA splits and the RNA comes in a copies a code from a strand until it reaches a “stop” code
Ex: photocopy of building blueprint
What is transcription?
The copying of a genetic message into a molecule of mRNA
What is a codon?
A group of three bases on mRNA that specifies an amino acid
EX: AUG is one codon
What is Transfer RNA or tRNA?
Complements mRNA and has anticodons not codons
What is translation?
The process by which the information coded in RNA is used for the assembly of a particular amino acid sequence
