Nucleic Acid Structure (Exam 1) Flashcards
What is DNA replication?
-DNA replicates itself
-needed for cell proliferation/duplication (cell division)
What is transcription?
DNA transcribed to RNA
What is translation?
RNA translated to protein
What is gene expression?
Transcription and translation (DNA to protein)
What is reverse transcription?
RNA to DNA (only retroviruses like HIV can do this)
What is G0?
Resting phase of cell cycle
What is G1?
Phase before synthesis (of cell cycle)
What is S of cell cycle?
Synthesis phase (duplication)
What is G2 of cell cycle?
Short phase right before mitosis
What is M phase of cell cycle?
Mitosis
Cell will be divided and then eventually go back to G0 or G1 phase depending on what the body needs/when
What is interphase?
G0, G1, S, G2 (everything but mitosis in the cell cycle)
Where does transcription occur?
In the nucleus
Where does translation occur?
In the cytoplasm
Where does DNA replication occur?
In the nucleus
What is the difference between gene expression and replication?
What are the 2 purines?
1) adenine
2) guanine
Pure As Gold
Note: purines have a shorter name, but larger structure
What do nucleotides consist of?
Base, sugar, and phosphate group(s)
What are the 3 pyrimidines?
1) cytosine
2) uracil
3) thymine
CUT = mnemonic to remember
Note: pyrimidines have a longer name, but smaller structure
What functional group sticks out in adenine?
amino group
What functional group sticks out in guanine?
carbonyl group
What functional group sticks out in cytosine?
amino group
What functional group sticks out in uracil?
carbonyl group
What functional group sticks out in thymine?
methyl group
What bases are found in DNA?
A, T, C, G
What bases are found in RNA?
A, U, C, G
What is a nucleoside?
nitrogen base + sugar
Is RNA single or double stranded?
single stranded
Is DNA single or double stranded?
double stranded
What bond connects the bases in DNA?
hydrogen bonds
3 hydrogen bonds between C-G
2 hydrogen bonds between A-T (would be A-U in RNA)
What bond holds the base to sugar?
N- glycosidic bond
What bond holds the phosphate to the sugar?
ester bond
What bond uses 2 oxygens from phosphate to connect to 2 sugars?
phosphodiester bond
What bond is between phosphate groups?
phosphoanhydride bond
What bond in DNA is more stable C-G or A-T?
C-G because its 3 hydrogen bonds (A-T is only 2 hydrogen bonds)
so more C-G= DNA is more stable
What are the 2 major rules/properties of dsDNA?
1) complementary pairs (A-T and C-G)
2) antiparallel sugar phosphate backbone
The correct structure of DNA components can be presented as:
A) phosphate-base-sugar
B) phosphate-sugar-base
C) base-phosphate-sugar
D) phosphate-sugar-phosphate-base
E) base-sugar-phosphate base
B) phosphate-sugar-base
What are the Chargaff rules?
dsDNA ONLY
- % of A= % of T
- % of G= % of C
- % of purines= % of pyrimidines
What is the complementary sequence of 5’ TAGAC 3’?
5’ GTCTA 3’
According to Chargaff’s rules, which of the following statements about dsDNA is true?
A) A=T and C=G
B) A+G= C+T
C) A+T = C+G
D) A and B
E) A, B, and C
D) A and B
What is primary structure in DNA?
the linear arrangement of the nucleotides in the polynucleotide
What bond forms primary structure in DNA?
phosphodiester bond
What structure is DNA double helix?
secondary structure
What is a right handed double helix?
-pentose sugar and phosphate face the outside environment (towards water)
-complementary base pairing
-antiparallel
-10 residues (nucleotides) per turn of DNA
There are 4 DNA conformations found in nature. Which type is predominated in cells?
B-DNA
What is B-DNA?
-dominant DNA form found in nature
-right handed helix
-sugar phosphate on the outside and bases on the inside (sugar phosphates like water)
What is chromatin?
-DNA + protein
-complex macromolecule found in cells, consisting of DNA and protein
What is nucleosome?
DNA + histone octamer
-basic unit of DNA packaging in eukaryotes
-consisting of a segment of DNA wound in sequence around 8 histone protein cores
Besides DNA and RNA, what are the other forms/functions of nucleotides?
-energy carriers (ATP, GTP, CTP, UTP)
-coenzymes (FAD, NAD, CoA)
-cellular communication with cAMP (carries messages from cell surface when hormone attaches)
are coenzymes active?
yes! They help enzymes function, its the active form of vitamins
What are the energy carriers we learned about?
-ATP
-GTP
-CTP
-UTP
can also be diphosphate or monophosphate, or have different base than adenine
anything ending with -ase=
enzyme
anything ending with -ose=
sugar
What is another name for riboflavin?
vitamin B2
What is the active form of riboflavin (vit B2)?
flavin adenine dinucleotide (in electron transfer), also known as FAD is the active form/coenzyme
will catch hydrogens for energy = FADH2
dinucelotide= 2 nucleotides (sugar, P, and base)
-the base here would be riboflavin
What is another name for nicotinamide?
vit B3, or niacin
What is the active form of nicotinamide (vit B3, or niacin)?
nicotinamide adenine dinucleotide (NAD) (transfers hydride)
What is another name for pantothenate?
vit B5
What is the active form of pantothenate (vit B5)?
CoA (coenzyme A, transfers an acyl group)
What are the 2 types of hormones?
lipid and protein
lipid hormones can easily get through cell membrane because of phospholipid bilayer, for ex: steroids
protein hormones like insulin and glucagon cannot penetrate cell membrane and need a 2nd messenger to get through
What is the major function of nucleotides?
make RNA and DNA
