Lecture 4a Flashcards
DNA
(deoxyribonucleic acid)
in the nucleus of eukaryotic cells
in the nucleoid region of the cytoplasm of prokaryotic cells.
RNA
(ribonucleic acid)
in the nucleus and in the cytoplasm of eukaryotic cells
in the cytoplasm of prokaryotic cells
Nucleic Acids are made up of …
polymers made up of monomers called nucleotides
DNA structure
1 molecule made up of 2 strands= Double helix
4 nucleotides: represented by the letters of the bases: A, T, G, C
It has 2 long polynucleotide strands linked together by hydrogen bonds between their nitrogenous bases
RNA structure
RNA is single stranded
It has 1 long polynucleotide strand that twists around itself (like a corkscrew to open wine bottles)
Types of RNA
mRNA
tRNA
rRNA
Complementary base pairing in DNA
A-T
C-G
Complementary base pairing in RNA
C-G
A-U
Complementary base pairing between DNA and RNA
A-U
C-G
Functions of nucleic acid
DNA: Store genetic information
RNA: Store, transfer, & express genetic information
The genetic material must
contain information necessary to build a whole organism.
be transmitted from parent to offspring.
To do this, the genetic material must first be replicated.
DNA contains …
- purpose of …
Contains genes:
tell cells which RNA & proteins to make
-needed to build the organism
How is the DNA passed on to offspring
Must be copied (DNA replication) before cell division
DNA composition
DNA = Genes + non-genes
Humans have ~ 21,000 genes
~2% of DNA is transcribed into RNA (mRNA, tRNA, or rRNA)
~98% of DNA= non-gene: Ex some DNA acts as genetic switches (controlling gene expression)
Gene
a specific segment of DNA that controls a hereditary characteristic
Structural or functional proteins
Arranged in a fixed order along the chromosome
