chapter 13-nucleic acids (kathleen dowd study guide)

Chemistry 102 with Freeman at University of South Carolina - All Campuses

About this deck

By: Jordan Campbell
Textbook:

General, Organic, and Biochemistry: Connecting Chemistry to Your Life
Created: 2010-12-01
Size: 24 flashcards
Views: 7

About StudyBlue

STUDYBLUE makes things that make you better at school. Things like online flashcards with photos and audio. Things like personalized quizzes and friendly reminders about when (and what) to study next. Think of it as a digital backpack™: access to all of your study materials online and on your phone. STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy

Sign up (free) to study this.

chromosomes

located in the nuclei of cells, contains the hereditary information that directs the synthesis of the approximately 100,000 proteins unique to a human being

*each contains a large # of genes

genes

the fundamental units of heredity. Genes are responsible for both the traits common to a species and for the unique traits of an individual member of that species

At the molecular level, the growth and reproduction of organisms are directed and carried out by what?

2 types of nucleic acids: ribonucleic acid (RNAs) and deoxyribonucleic acid (DNAs)

*chromosomes contain DNA molecules. each gene is a part of a DNA molecule.

*DNA contains hereditary info and directs its own reproduction and the synthesis of RNA

*RNA molecules leave the cell nucleus and direct the synthesis of proteins in ribosomes

Nucleotides

the building blocks of nucleic acids which are hydrolyzable into 3 components:

*Phosphoric acid

*Pentose sugar (in RNA=D-ribose. In DNA=2-deoxy-D-ribose)

*Heterocyclic nitrogen base

Heterocyclic nitrogen base

*a total of 5 different heterocyclic bases are used: 3 pyrimidine and 2 purine bases

--C-cytosine

--T-thymine

--U-uracil

--A-adenine

--G-guanine

*A, G, and C are inboth RNA and DNA. T is only in DNA, and U is only in RNA

Formation of Nucleotides

occurs by 2 dehydration reactions among the 3 components

*one dehydration between phosphoric acid and pentose sugar

--takes place on C5 of pentose ring

*one dehydration between pentose sugar and heterocyclic base

--takes place on C1 of pentose ring and at an N-----H hydrogen on heterocyclic base

ribonucleotides

nucleotides derived from ribose

deoxyribonucleotides

nucleotides derived from deoxyribose

Naming Nucleotides

first word of name indicates the sugar and base components

--the part of the molecule compose of the purine base and sugar is named by replacing the ending -ine of the base with -osine. Ex. adenosine=adenine+sugar

*the pyrimidine bases-cytonsine, thymine, and uracil--combined with sugar are named cytodine, thymidine, and uridine

*when deoxyribose is the sugar, the prefix deoxy-is used

naming nucleotides cont

5'-Monophosphate is the second word in the name, indicating the phosphate group at C5' of the sugar

Nucleotides are often abbreviated:

*the prefix deoxy-is shortenend to d- and is followed by the one-letter symbol for the abse (C,T, U, A, G) and MP is used for 5'-monophosphate

*ex. deoxycytidine 5'-monophosphate=dCMP

Formation of Nucleic Acids

Nucleic acids are polynucleotides that are formed from the dehydration of the nucleotides

*dehydration reaction occurs btw the -OH of the phosephate group at C5' of one nucleotide and the -OH at C3' of another nucleotide

*by convention, nucleotide sequences are named in the 5'->3' direction. A nucleic acid has a 5' end and a 3' end

Deoxyribonucleic Acids (structure)

*DNA double helix- 2 paired DNA molecules (called DNA strands) fold or coil around each other to form a right-handed double helix. The 2 strands run in opposite directions, one in the 5'->3' direction and the other in a 3'->5' direction

*2 types of forces stabilize the DNA double helix: hydrogen bonding and hydrophobic attractions

DNA acids cont (structure)

strong hydrogen bonding forces between a base on one DNA strand and a base on the other DNA strand. This attraction is called base-pairing, and the bases pair in a complementary manner (A-T and G-C). This creates complementary strands

*A and T result in 2 hydrogen bonds

*G and C result in 3 hydrogen bonds

DNA acids cont (structure)

DNA stranda are enormous molecules

*human genome-total DNA in humans, about 3.2 billion base pairs

*DNA contained in 23 pairs of chromosomes

*all DNA is compacted into the nucleus via its double helix form around structures called nucleosome cores

-each core composed of 2 pairs each of 4 diff proteins called histones

-DNA duplex wraps around nucleosome cores to form nucleosomes, with about 150-200 base pairs per nucleosome

-tightly compacted into highly super coiled chromatin fiber-makes chromosome

Ribonucleic Acids

*exist as single strand molecules

*several types of RNA exist with its own specific 3D structure

-transfer RNS or tRNA

-ribosomal RNA or rRNA

-messenger RNA or mRNA

*secondary & tertiary structures arise from base-pairing of nucleotides, just like DNA except that T is replaced with U

-A-U

-G-C

RNA Acids cont.

information flow from DNA-RNA-Polypeptide

*genetic info is stored in DNA as a sequence of bases. The sequences correspond to a specific sequence of amino acids in polypeptides. Since DNA is too large to leave the nucleus, it must direct its own replication with the smaller molecule RNA to go out into the cytosol and carry out protein synthesis

-Replication

-Transcription

-Translation

Replication(minor detail)

copying of DNA in the course of cell division

Transcription(minor detail)

is the synthesis of RNA from DNA. 3 types of RNA molecules are produced: rRNA, tRNA, and mRNA

Translation(minor detail)

is the synthesis of polypeptides through the combined efforts of rRNA, tRNA, and mRNA

Replication

-complex process involving dozens of enzymes

-DNA strands unwind over a short span of 150-200 nucleotides forming a replication bubble with a replication fork at each end. each strand acts as a template strand on which a complementary strand is synthesized

-new bases are added in the 5'->3' direction

-a single parent DNA molecule is transformed into 2 daughter DNA molecules, each containing an old & a new DNA strand (semiconservative)

Transcription

*synthesis of rRNA, mRNA, and tRNA w/ use of info from DNA

*DNA double helix unwinds to form transcription bubble. only 1 of 2 DNA strands in the bubble, called template strand, is used as template for RNA synthesis. other strand not used at all

*begins at initiation site whose base sequence is recognized by RNA polymerase as a start signal and ends at a termination site, a base sequence recog as a stop signal

*base pairing determines base sequence of RNA made from a DNA model except A w/ U not T

Translation

*process by which rRNA, mRNA, and tRNA work together outside nucleus to carry out polypeptide synthesis

*polypeptides made at structures called ribosomes located in the cytosol

Translation cont.

*messenger RNA carries genetic message encoding the amino acid sequence of the polypeptide to be synthesized in the ribosome,binds to the ribosome, and acts as the template for polypeptide synthesis

-genetic message is the sequence of RNA bases, which specifies the sequence of α-amino acids to be synthesized

Translation cont.

-each successive set of 3 consecutive bases (base triplet) in mRNA is called a codon because it codes for one specific tRNA that carries one amino acid. (3 RNA bases=1 codon=1 anticodon(3 tRNA bases)=1 amino acid)

*tRNA transports α-amino acids into the ribosome for synthesis

-the codon of mRNA recognizes its specified tRNA through a base triplet, or anticodon, which carries the specific amino acid sequence

About this deck

By: Jordan Campbell
Textbook:

General, Organic, and Biochemistry: Connecting Chemistry to Your Life
Created: 2010-12-01
Size: 24 flashcards
Views: 7

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy