Chp. 8 slides 1-26 Flashcards
Bleh
What is genetics?
The science of heredity
What controls gene expression?
Operons
What are three things altering genes do?
- Cause disease
- Prevent disease treatment
- Manipulated for human benefit
The study of genes and how they carry information is called _____
Genetics
Structures containing DNA that physically carry hereditary information is called _______
Chromosomes
Segments of DNA that encode functional products, usually proteins, is known as ______
Genes
All the genetic information in a cell is called a ______
Genome
What is the central dogma in Biology?
- Genetic information goes from DNA to RNA to proteins.
- DNA to RNA through transcription
- RNA to proteins through translation
The genome of cells are from ___ whereas the genome of viruses are from ___ or ___
- DNA
- DNA or RNA
What are chromosomes made up of?
DNA complexed with protein
Which chromosomes are a single circular loop?
Which chromosomes are multiple and linear?
- Bacterial chromosomes
- Eukaryotic chromosomes
What are the 3 categories of genes and their functions?
- Structural genes: code for proteins
- Genes that code for RNA
- Regulatory genes: control gene expression
What is the difference between genotypes and phenotypes?
- Genotype: consists of the genetic makeup
- Phenotype: consists of observable physical traits
Rank these genomes from least genes to most genes:
E. Coli, Human cell, Smallest virus
- Smallest virus: 4-5 genes
- E. coli: 4288 genes
- Human cell 31,000+ genes
The basic unit of a DNA structure is a ________
Nucleotide
What are introns and exons?
Exons: coding regions that code for protein
Introns: non coding regions that do not code for any protein
What are the 3 parts of a nucleotide?
- 5 carbon sugar
- Phosphate group
- Nitrogenous base (AGCT)
How are nucleotides covalently bonded?
Each sugar is attached to two phosphates in a 5’ to 3’ direction
What does it mean when a nucleotide is bonded in a 5’ to 3’ direction?
The phosphate is known as the 5’ and it attaches to the hydroxyl group which is 3’. They ALWAYS attach to each other.
When DNA is wrapped around histones, it is known as a _______
Nucleosome
Define supercoiling
When DNA takes a nucleosome and turns it into a coil
Why is it harder to pull apart a C-G bond than a A-T bond?
C-G has 3 hydrogen bonds whereas A-T has only 2 hydrogen bonds
What are two examples of the significance of DNA structure?
- Maintenance of code during reproduction: constancy of base pairing guarantees that the code will be retained
- Providing variety: order of bases responsible for unique qualities of each organism
What is the genetic code?
The rules that determine how a nucleotide sequence is converted to an amino acid sequence of a protein
The repeating sequences of noncoding DNA are known as _______
Short tandem repeats (STRs)
The flow of genetic information from one generation to the next is known as _______
Vertical gene transfer (goes from parent cell to daughter cell)
How does horizontal gene transfer work?
It happens in the same generation through conjugation.
The donor cell makes a copy of its DNA then attaches to its recipient cell
What does the DNA “backbone” consist of?
How are the two strands of nucleotides held together?
- Deoxyribose-phosphate
- The hydrogen bonds between A-T and C-G
True or False: Less than 2% of our DNA are coding DNA
TRUE
98% of our DNA are considered “non coding”
What is the purpose of topoisomerase and gyrase?
To relax the DNA strands
What is the purpose of helicase?
To separate the DNA strands
What is the purpose of primase?
To put RNA primer
What are okazaki fragments?
Short DNA fragments formed on the lagging strand during DNA replication
Describe the process of DNA replication pt. 1
- One strand serves as the template for the production of a second strand
- Topoisomerase and gyrase relax the strands
- Helicase will open the DNA by breaking the hydrogen bonds (aka unzipping)
Describe the process of DNA replication pt. 2
- Primase will add RNA primer (18-25 single stranded nucleotides that will find complementary bases and bind to it) to the strands
- DNA polymerase III will add DNA nucleotides to the new DNA being formed
- DNA polymerase I comes and removes RNA primer and replaces it with DNA nucleotides
- Ligase attaches DNA fragments together
What does the overall replication process achieve?
The replication occurs on both strands simultaneously
- Creates complementary strands and is a semiconservative replication process (end up with one parent and one daughter strand)
Which is the leading strand and which is the lagging strand?
Bottom: leading
Upper: lagging
True or False: Viruses cannot go from RNA to DNA
FALSE
Since it is not a living organism, viruses have the ability to go from DNA to RNA AND RNA to DNA
