Chapter 14 Flashcards
Polymer made up of monomers. A nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms.
DNA
Monomer of nucleic acids. DNA and RNA are made up of this.
Nucleotides
Nucleic Acid Structure Include:
1.) Nucleotides
2.) Strand
3.) Double Helix- wrapped around proteins to form chromosome
4.) Chromosome
5.) Genome
Building blocks of DNA/RNA.
Nucleotide
What bases is included of nucleotides?
sugar, phosphate, nitrogenous base
What are the strands that make up nucleotides?
adenine, guanine, thymine, cytosine, and uracil
What are differences between DNA nucleotide and RNA nucleotide?
DNA nucleotide:
sugar– deoxyribose
base–ATCG
double stranded
RNA nucleotide:
sugar–ribose
base– AUCG
single stranded
Covalently bonded. Composed of covalently linked nucleotides–phosphodiester linkage. Directionality 5’ to 3’
Nucleic Acid Structure –Strand
Orientations are opposite of one another
Antiparallel
5’–>3’
3’<–5’
Sugar phosphate backbone. Hydrogen bonding between bases (ATCG).Two strands are complimentary, antiparallel
Nucleic Acid Structure–Double Helix
Complimentary Strands are?
A–T
C–G
She developed the method of X-ray diffraction of wet DNA fibers. X rays diffracted by DNA onto photographic plate. Pattern represents the atomic array in wet fibers.
Rosalind Franklin
Discovered Content in the DNA rom a Variety of Organisms. Observed that the nucleotide composition of DNA varies between species, but not between individuals of the same species. Was the first to accurately measure the amounts of nucleotides in DNA.
Edwin Chargaff
Who discovered double helix of DNA?
Watson and Crick. Proposed structure of DNA in 1953.
DNA wrapped around proteins and all crammed together
Nucleic Acid Structure–Chromosome
All genetic information
Nucleic Acid Structure– Genome
How DNA replicates/make copies of itself:
-Semi-conservative
- origin of replication
- replication forks
Original DNA strands (parents) used as templates to make new DNA strands or the original double helix is used as templates to make new DNA strands.
Semi-conservative
Where DNA replication starts. This site within a chromosome is where replication begins.
origin of replication
What has a lot of origins of replication?
Eukaryotes
Leading and lagging (Ozaki fragments) strands. Inside of origin of replication. Where replication forks
Replication forks
DNA must be made in the what direction?
The 5’ to 3’ directions
Proteins involved in replication preparation: ALL SEPARATE DOUBLE HELIX
- DNA helicase
- DNA topoisomerase
- Single strand binding proteins
Separate strands. Separates original double helix. Breaks hydrogen bonds.(unzipping a gene). This enzyme separates the double strand of DNA so replication can begin.
DNA helicase
Alleviates coiling. Keeps it from getting tangled. This enzyme alleviates supercoiling during replication.
DNA topoisomerase
Keeps strands part. Keep double strands separated. These proteins keep DNA separate so replication can occur.
Single strand binding proteins
Proteins involved in replication:
- DNA primase
- DNA polymerase
- DNA ligase
Adds short sequence of RNA. Tells it where to start copying. This enzyme adds a short segment of RNA so replication can begin.
DNA primase
Adds nucleotides, removes RNA primers, fills gaps. Makes new DNA; proof reads itself. Able to covalently link nucleotides together from a primer. Can only link nucleotides in 5’ to 3’ direction. This enzyme is responsible for adding nucleotides together to form DNA strands.
DNA polymerase
Work only on lagging strand because its only (Okazaki fragments). Attaches adjacent Okazaki fragments. This enzyme links together Okazaki fragments.
DNA ligase
Hydrogen bonding between A and T or G and C more stable than mismatches. Active site of DNA polymerase unlikely to form bonds if pairs mismatched. DNA polymerase removes mismatched pairs. Proofreading results in DNA polymerase backing up and digesting linkages. Other DNA repair enzymes.
DNA replication is very accurate
Composed of chromatin. DNA protein complex.
2 parts:
DNA wrapping and 30 nm fiber
Chromosomes
DNA wrapped around histones to form nucleosome. Shortens length of DNA molecule 7-fold. Needs to be wrapped to fit and be small enough (for cells/nucleus)
DNA wrapping–Chromosomes
Shortens length another 7-fold
30 nm fiber
Which of the following is FALSE when comparing RNA and DNA?
A.) Both are produced by phosphodiester linkages.
B.) Both are composed of phosphate groups.
C.) Both are composed of sugars.
D.) Both are composed of identical nucleotides.
E.) Both are composed of a phosphate group, a pentose sugar, and a nitrogenous base.
D.) Both are composed of identical nucleotides.
What is the complement DNA strand to 5’- ATTCGGTGA–3’?
A.) 5’–TAAGCCACT–3’
B.) 3’–CGGATTGTC–5’
C.) 5’–CGGATTGTC–3’
D.) 3’–TAAGCCACT–5’
E.) 3’–ATTCGGTGA–5’
D.) 3’–TAAGCCACT–5’
Produces short sequences of RNA, which allows polymerase to synthesize a new strand of DNA.
A.) DNA primase
B.) DNA helicase
C.) DNA polymerase
D.) DNA topoisomerase
E.) DNA ligase
A.) DNA primase
The process of making new DNA from preexisting DNA.
replication
This newly synthesized strand of DNA is made in one continuous motion.
leading
Chromosomes consist of DNA wrapped around these proteins.
Histone
This newly replicated lagging strand of DNA is made is these short fragments.
Okazaki fragments
