Nucleic acids and their function

Bio exam 2

What are the polymers of nucleotides

Nucleic acids

What are the monomers of nucleic acids?

Nucleotides

What are the three components of nucleotides?

phosphate group, five carbon sugar, nitrogenous base

what is a nitrogenous base?

a nitrogen containing base

Where are the nitrogenous bases and phosphate group present in nucleotides?

Bonded to the five carbon sugar

What are the monomers of RNA?

ribonucleotides

What are the monomers of DNA?

deoxyribonucleotides

what five carbon sugar is present in ribonucleotides?

ribose

what five carbon sugar is present in deoxyribonucleotides?

deoxyribose

what does deoxy mean?

lacking oxygen

What are the two groups of nitrogenous bases?

Purines and pyrimidines

What are the some kinds of purines?

Adenine (A) and Guanine (G)

What are the some kinds of pyrimidines?

Cytosine (C), Uracil (U), Thymine (T)

What is bonded to the 2’ carbon in ribonucleotides?

an -OH group

What is bonded to the 2’ carbon in deoxyribonucleotides?

an H

Where is Uracil only found?

found only in ribonucleotides

Where is Thymine only found

found only in deoxyribonucleotides

Are purines or pyrimidines larger

Purines

how many atoms are in purines?

nine atoms in their two rings

how many atoms are in pyrimidines?

six atoms in their one ring

What is this?

A nucleotide

What sugar is this?

Ribose

What sugar is this?

deoxyribose

What is this?

deoxyribonucleotide

How do nucleic acids polymerize?

Condensation reactions

Where does phosphodiester linkage occur?

Between the phosphate group attached to the 5’ carbon of one nucleotide and -OH group on the 3’ carbon of another

what polymer(s) are produced from phosphodiester linkage?

RNA and DNA

What is this?

phosphodiester linkage +condensation reaction

What do phosphodiester linkages form?

sugar-phosphate backbones

sugar-phosphate backbones are

directional

How is the primary structure of DNA written

listing sequence of bases by single letter abbreviations
5’-ATTAGC-3’

Nucleotide polymerization reaction is

spontaneous, energy is released

What are activated nucleotides?

nucleotides triphosphates, two additional phosphate groups are added to the nucleotide

What is a kind of activated ribonucleotide?

Adenosine triphosphate (ATP)

How is the spontaneity of nucleotides altered to make their polymerization spontaneous?

they are bonded to enzymes, two additional phosphate groups are added

What does antiparallel mean?

parallel but in opposite directions, in DNA this means 5’___3’ and 3’___5’

What is the secondary structure of DNA?

double helix

What causes double stranded DNA to twist into helix shape?

hydrophobic reactions (stacking)

what stabilizes DNA strands?

van der waals interactions

what different sized grooves do DNA have?

1. major groove

2. minor groove

Label 1 and 2

1. major groove

2. minor groove

what holds the nitrogenous bases together in a DNA double helix?

hydrogen bonds

DNA strands in a double helix are

complementary and antiparallel

G is to C as

A is to T

What are the forms of DNA tertiary structure?

coils, supercoils, histones

What are histones?

DNA binding proteins that eukaryotic DNA wraps around

what is a nucleosome?

DNA double helix wrapped around groups of histones

what kind of bonds hold DNA double helix together?

phosphodiester linkages, hydrogen bonds, hydrophobic interactions

Why is the stability of DNA important?

needs to be a reliable information-storage molecule

What makes DNA stable and resistant to degredation?

functional groups

What does DNA do?

stores information required for organism’s growth and reproduction

How is information stored on DNA?

on the four nitrogenous bases (function like letters in an alphabet, sequence of bases have meaning)

How many steps are there in DNA replication?

3

What is the first step of DNA replication?

Two strands are separated by breaking hydrogen bonds

What is the second step of DNA replication?

free deoxyribonucleotides form hydrogen bonds w complementary bases on original strand of DNA (template strand)

(phosphodiester linkages form to create new strand (complementary strand))

What is the third step of DNA replication?

complementary base pairing allows each strand to be copied exactly producing two identical daughter molecules

What is the primary structure of RNA?

four types of nitrogenous bases extending from sugar-phosphate backbone

How does the primary structure of RNA differ from DNA?

RNA contains ribose instead of deoxyribose

RNA contains uracil instead of thymine

2’ -OH group on ribose is more reactive than -H
RNA is much less stable than DNA

A is to U as

G is to C

where does RNA form hydrogen bonds?

with complementary bases on the same strand

What is the secondary structure of RNA

hairpin/stem/loop structure

What is this?

RNA secondary structure

How does the secondary structure of RNA form?

Bases on one part of RNA strand fold over and align with bases on other part of the same strand

How does the tertiary structure of RNA formed?

when secondary structures fold into more complex shapes

What can RNA do?

information-containing molecule, capable of self-replication, capable of catalyzing reactions: ribozymes

What is the tertiary structure of DNA?

double helical DNA forms compact structures by wrapping around histone proteins or twisting into supercoils