Made by Stephanie Mazambi
3.4.1 DNA, genes and chromosomes
Describe Eukaryotic DNA - Long
- Linear
- Associated w/ Histones (proteins)
- Coiled
Describe Prokaryotic DNA - Short
- Circular
- Not Associated w/ Histones
(proteins)
Describe DNA in mitochondria and - Similar to prokaryotic DNA
chloroplasts - sHORT
- Circular
- Not associated with proteins
What is a gene? Section of DNA that codes for the amino
acid sequence of a polypeptide and
functional RNA (tRNA and rRNA)
What is a locus/loci? Specific linear position of a gene on a
certain chromosome
What is a histone? Proteins which together with DNA
What is the nature of the genetic code? ● Triplet (sequence of three dna
bases) for specific amino acid
● Universal
● Non-overlapping
● Degenerate
What is an exon? Portion(s) of DNA within a gene that codes
for proteins
What is an Intron? Portion(s) of DNA within a gene that does
not code for proteins
What is an Allele? Alternative form of a gene with different
base sequences (and therefore codes)
Define genome The complete set of genes in a cell
Define proteome The full range of proteins that a
call/genome is able to produce
Define Homologous Pair of chromosomes Pair of chromosomes with the same gene
but different alleles
3.4.2 DNA and protein synthesis
Describe the structure of messenger RNA - Single stranded
(mRNA) - Straight chain helix
- Made during transcription
, Made by Stephanie Mazambi
- Codon
- Pentose sugar = ribose
- A,C,G,U = bases
Describe the structure of Transfer RNA - Single polynucleotide chain
(tRNA) - Ribose
- Three leafed Clover-shaped
molecule
- Amino acid binding site
- Anticodon
- Held by hydrogen bonds
- short
What are similarities between trna and Both single polynucleotide strands
mrna?
What are the differences between tRNA and - mRNA single helix / straight, whereas
mRNA? tRNA folded into clover shape
- mRNA is a longer, variable length,
whereas tRNA is shorter
- mRNA contains no paired bases or
hydrogen bonds, whereas tRNA has some
paired
bases and hydrogen bonds
Describe the process of Transcription 1. Occurs in the nucleus
2. DNA helix unwound by DNA
Helicase = Hydrogen bonds broken
3. Formation of template strand
4. RNA nucleotides align next to
exposed nucleotide bases on
template strand
5. RNA polymerase joins adjacent
nucleotides through
condensation reaction
6. Forms phosphodiester bonds
7. When reached to stop codon
pre-mRNA detached from DNA
8. Splice the pre-mRNA (removal on
introns)
9. Creation of mMRNA
What is meant by post transcriptional Splicing of Pre-mRNA
modification?
Describe the process of Translation 1. mRNA attaches to ribosomes
2. tRNAs codon binds to mRNA codon
3. Begins with start codon
4. tRNA will attract specific amino
acids with two trna molecules at a
time
3.4.1 DNA, genes and chromosomes
Describe Eukaryotic DNA - Long
- Linear
- Associated w/ Histones (proteins)
- Coiled
Describe Prokaryotic DNA - Short
- Circular
- Not Associated w/ Histones
(proteins)
Describe DNA in mitochondria and - Similar to prokaryotic DNA
chloroplasts - sHORT
- Circular
- Not associated with proteins
What is a gene? Section of DNA that codes for the amino
acid sequence of a polypeptide and
functional RNA (tRNA and rRNA)
What is a locus/loci? Specific linear position of a gene on a
certain chromosome
What is a histone? Proteins which together with DNA
What is the nature of the genetic code? ● Triplet (sequence of three dna
bases) for specific amino acid
● Universal
● Non-overlapping
● Degenerate
What is an exon? Portion(s) of DNA within a gene that codes
for proteins
What is an Intron? Portion(s) of DNA within a gene that does
not code for proteins
What is an Allele? Alternative form of a gene with different
base sequences (and therefore codes)
Define genome The complete set of genes in a cell
Define proteome The full range of proteins that a
call/genome is able to produce
Define Homologous Pair of chromosomes Pair of chromosomes with the same gene
but different alleles
3.4.2 DNA and protein synthesis
Describe the structure of messenger RNA - Single stranded
(mRNA) - Straight chain helix
- Made during transcription
, Made by Stephanie Mazambi
- Codon
- Pentose sugar = ribose
- A,C,G,U = bases
Describe the structure of Transfer RNA - Single polynucleotide chain
(tRNA) - Ribose
- Three leafed Clover-shaped
molecule
- Amino acid binding site
- Anticodon
- Held by hydrogen bonds
- short
What are similarities between trna and Both single polynucleotide strands
mrna?
What are the differences between tRNA and - mRNA single helix / straight, whereas
mRNA? tRNA folded into clover shape
- mRNA is a longer, variable length,
whereas tRNA is shorter
- mRNA contains no paired bases or
hydrogen bonds, whereas tRNA has some
paired
bases and hydrogen bonds
Describe the process of Transcription 1. Occurs in the nucleus
2. DNA helix unwound by DNA
Helicase = Hydrogen bonds broken
3. Formation of template strand
4. RNA nucleotides align next to
exposed nucleotide bases on
template strand
5. RNA polymerase joins adjacent
nucleotides through
condensation reaction
6. Forms phosphodiester bonds
7. When reached to stop codon
pre-mRNA detached from DNA
8. Splice the pre-mRNA (removal on
introns)
9. Creation of mMRNA
What is meant by post transcriptional Splicing of Pre-mRNA
modification?
Describe the process of Translation 1. mRNA attaches to ribosomes
2. tRNAs codon binds to mRNA codon
3. Begins with start codon
4. tRNA will attract specific amino
acids with two trna molecules at a
time
