AP Bio OR

A molecule of messenger RNA (mRNA) has just been synthesized in the nucleus of a human cell. What types of modification may occur to the RNA before it leaves the nucleus?

capping and splicing

Describe ONE difference in prokaryote and eukaryote transcription.

- Prokaryotes: mRNA produced by transcription is immediately translated without additional processing - Eukaryotes: pre-mRNA is processed in various ways before leaving the nucleus as mRNA. Ex: Capping and splicing

Describe structural changes that can occur in a protein after translation to make it function properly.

Activation into a functional protein through cleavage of certain amino acid sequences; the amino acid sequence can fold to form the secondary or tertiary structure

Describe the adaptive (evolutionary) significance of organizing genes into chromosomes.

Allows for genetic variation by independent assortment and crossing over

The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of biology. a). Explain the role of each of the following in protein synthesis in eukaryotic cells. - RNA polymerase - Spliceosomes (snRNPs) -Codons -Ribosomes -tRNA

RNA polymerase- It unwinds DNA and makes mRNA Spliceosomes (snRNPs)- Cuts out introns and puts together exons Codons- They code for specific amino acids Ribosomes- Help to assemble proteins tRNA- Carries amino acids to ribosome

Once in the cytoplasm how is the mRNA translated to a protein?

Ribosomes attach to the start of the mRNA and brings over the necessary amino acids which form a peptide chain

Describe the structure and function of the parts of a eukaryotic chromosome. You may wish to include a diagram as part of your description.

Chromatids 2/sister/pair/identical DNA/genetic information Distribution of one copy to each new cell Centromere noncoding/uncoiled/narrow/constricted region/ determines arm ratio joins/holds/attaches chromatids together Nucleosome Histones, DNA wrapped around special proteins Packaging compacting Chromatin Form Condensed/supercoiled Proper distribution in cell division Kinetochores Disc-shaped proteins Spindle attachment/alignment Telomeres Tips, ends, non-coding repetitive sequences Protection against degradation/aging, limits number of cell divisions

Identify ONE differences between transcription and translation.

Transcription: products are mRNA, tRNA, rRNA, and non-coding RNA; take place in the nucleus Translation: product is protein; takes place in the cytoplasm

Explain how the protein gets to the rough ER

a signal recognition particle, or SRP, recognizes signal peptide produced from a free ribosome directs the ribosome and new protein to the rough ER.

Identify ONE similarity between transcription and translation.

mRNA is involved in both processes and they both aid in the synthesis of proteins

How does the function and structure of the chromosome differ in prokaryotes?

Chromosomes shape are smaller, less complex, and are circular in shape.

Contrast all of the following activities in prokaryotes and eukaryotes - DNA - Transcription - Ribosomes

PROKARYOTES -Dna: found freely in the cytoplasm -Transcription: no RNA processing, occurs in the cytoplasm -Ribosome: small ribosome EUKARYOTES -Dna: membrane bound in the nucleus -Transcription: RNA processing, occurs in the nucleus -Ribosome: larger ribosome

Cells regulate both protein synthesis and protein activity. Discuss TWO specific mechanisms of protein regulation in eukaryotic cells.

Promoter- increase RNA polymerase binding Alternative Splicing- editing in different ways to get new/different RNA/polypeptides

Protein synthesis is vital for cell growth and metabolism for both prokaryotes and eukaryotes. Describe transcription and translation

transcription- is the synthesis of RNA on a DNA template translation- is the synthesis of a polypeptide, which occurs under the direction of the messenger RNA (mRNA).

Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecules must (1) copy itself precisely (2) be stable but be able to be changed and (3) be complex enough to determine the organism's phenotype. Explain how DNA meets each of the 3 criteria stated above.

1. It undergoes dna replication which forms a new dna from the original strand 2. has a stable double helix shape but can be unzipped during replication 3. has a specific code or nucleotide sequence

Select one of the criteria stated above and describe experimental evidence used to determine that DNA is the hereditary material.

Hershey and Chase conducted an experiment with bacteriophages, one with the protein radioactively labeled and the other with dna radioactively labeled. When both were injected into the bacteria the dna was what entered the cell which meant that DNA is the genetic material.

A difference between prokaryotes and eukaryotes is seen in the organization of their genetic material. Discuss the organization of the genetic material in prokaryotes and eukaryotes.

PROKARYOTES -no introns -not in nucleus -circular -no histones -usually one chromosome -plasmids common -supercoiled DNA EUKARYOTES -introns -in nucleus -linear -histones -usually more than one chromosome -plasmids rare -chromatin DNA