Genetics and Molecular Biology Concepts

Mendel's contribution

Mechanism of hereditary traits by cross-breeding pea plants

Trait variations are called

Alleles

Genotypic ratio: heterozygous tall × short

1:1 (Tt:tt)

Phenotypic ratio: homozygous tall × heterozygous tall

All tall (4:0)

Trait between dominant and recessive

Incomplete dominance

Color blind daughter from carrier woman × unaffected man

0% chance

Sex-linked traits are found on

X chromosome

ABO blood type is an example of

Multiple alleles

AB blood type shows

Co-dominance

Wavy hair (curly + straight) is an example of

Incomplete dominance

Barr body

Inactive X chromosome seen in calico cats

Cause of Down syndrome

Trisomy of chromosome 21

Locus

Location of a gene on a chromosome

Test cross

Used to determine genotype of dominant individual

Griffith's discovery

Dead bacteria can transform harmless bacteria into harmful

Hershey & Chase

Proved DNA carries genetic info using tagged bacteriophages

Nucleotide parts

Sugar, phosphate, nitrogen base (A, T, G, C)

DNA bond

Hydrogen bonds between bases

Antiparallel part of DNA

Pentose sugars

DNA replication

During S phase in nucleus

Watson & Crick

Discovered DNA structure (Nobel Prize)

Genetic code

Order of nitrogen bases

Chargaff's rule

A = T, C = G

Rosalind Franklin

Used x-ray crystallography to show DNA shape

DNA-RNA base pairs

A-U, T-A, G-C, C-G

Central Dogma

DNA → RNA → Protein (Transcription in nucleus, Translation in cytoplasm)

mRNA modification

5' cap, 3' poly-A tail, splicing introns/exons

Codon

3 bases on mRNA

Anticodon

3 bases on tRNA

120 nitrogen bases

40 amino acids

What forms between tRNAs in ribosome

Peptide bond

Mutation

Change in DNA, can lead to tumors

Cloning

Implanting nucleus into egg cell

Plasmid

Extra circle of DNA used in recombinant tech

Restriction enzymes

Cut DNA at specific points

Therapeutic cloning

Using clones to repair tissues

Gel electrophoresis

Sorts DNA by size using electric charge

PCR

Technique to make many DNA copies

Gene expression

Production of a functional protein

DNA sequencing

Finding the order of nitrogen bases

DNA ACA → mRNA

UGU (Cysteine)

DNA ACT → mRNA

UGA (Stop codon)

mRNA GCU CAA UCC

Alanine, Glutamine, Serine

Does GCU → GCA change amino acid?

No

Does CAA → CAC change amino acid?

Yes (Glutamine → Histidine)