DNA Replication

What happens during interphase in DNA Replication?

- End result is two identical strands of DNA, each half of the original and half new

What is the "Central Dogma"?

The flow of genetic information in a cell

Transcription

Making mRNA from a DNA template using the enzyme RNA polymerase

RNA

URSingle:

• Uracil instead of thymine

• Ribose

• SINGLE stranded

Translation

nucleic acid language to amino acid language

How does mRNA code for proteins?

mRNA codes for proteins in triplets: codons

Start Codon

AUG which codes for methionine

Stop Codons

UGA, UAA, UAG

Where is DNA located in prokaryotes?

In the cytoplasm

What type of chromosome do prokaryotes have?

Circular chromosome

What is unique about prokaryotic DNA?

It is naked DNA

Do prokaryotes have introns?

No, they do not have introns

Where is DNA located in eukaryotes?

In the nucleus

What type of chromosomes do eukaryotes have?

Linear chromosomes

What are eukaryotic DNA wound around?

Histone proteins

Do eukaryotes have introns and exons?

Yes, they have introns vs. exons

Intron

noncoding (inbetween) sequence

Exon

coding (expressed) sequence

mRNA

transcribes message from DNA into RNA so it can leave the nucleus

rRNA

makes up the ribosomes

tRNA

delivers amino acids to the ribosome

Compare and contrast gene and chromosome mutations.

A gene mutation only affects one base pair, but a chromosome mutation affects an entire chromosome or a large chunk of a chromosome.

Explain what happens in nondisjunction during meiosis resulting in conditions like Down Syndrome, Turner Syndrome, and Klinefelter Syndrome.

Nondisjunction is when instead of going to opposite ends of a cell during meiosis, homologous chromosomes go to the same side. This results in too many chromosomes in one gamete and not enough in the other. Depending on which chromosome is affected, this could lead to different genetic disorders.