DNA & Protein Synthesis

noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein.

introns

carries amino acids and drops them off at the ribosome and mRNA.

Transfer RNA

Explain the central dogma and why a two step-process is necessary in order to make proteins.

describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein. Transcription is the synthesis of an RNA copy of a segment of DNA.

"above" or "on top of" genetics. It refers to external modifications to DNA that turn genes "on" or "off." These modifications do not change the DNA sequence, but instead, they affect how cells "read" genes; a system by which the gene expression of an individual can be altered without altering their genome's sequence.

epigenetics

predict a consequence for an error made during transcription and translation

errors that occur during transcription and translation can also have substantial effects on gene function by producing misfolded and malfunctioning proteins. Therefore, a single transcription error can result in many flawed proteins, whereas a translation error will disrupt only a single protein.

explain the difference between epigenetics and mutations

A genetic mutation is a hardcopy change in one or more parts of that sequence. This could just make you, you. Or it could contribute to a genetic disease. An epigenetic change also changes a gene's DNA — but not at the sequence level.

describe an example of how gene expression is regulated

First, transcription is controlled by limiting the amount of mRNA that is produced from a particular gene. The second level of control is through post-transcriptional events that regulate the translation of mRNA into proteins.

explain how the mRNA is modified after transcription

In splicing, some sections of the RNA transcript (introns) are removed, and the remaining sections (exons) are stuck back together. Some genes can be alternatively spliced, leading to the production of different mature mRNA molecules from the same initial transcript.

Explain the base pairing rules of DNA. Provide an example of a strand of DNA with its complementary strand.

Nitrogen bases bond only to their complementary base pair w/ weak hydrogen bonds. A-T C-G Strand: TTAG Complementary: AATC

a chain of nucleotides which stores genetic information in biological systems. It creates DNA and RNA, which store the information needed by cells to create proteins. This information is stored in multiple sets of three nucleotides, known as codons.

Nucleic acid

Difference between purines and pyrimidines and which nitrogen bases are which.

Purines are nitrogen bases that have the bigger bases while Pyrimidines are nitrogen bases that have the smaller bases. Purines: Adenine, Guanine Pyrimidines: Cytosine, Thymine

Enzyme that synthesizes short RNA sequences; functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA, which serves as its template. It is critical that primers are synthesized by primase before DNA replication can occur.

RNA Primase

binds the amino acids together with peptide bonds.

Ribosomal RNA

set of 20 different molecules used to build proteins. The sequence of this chain causes the polypeptide to fold into a shape that is biologically active. These sequences of proteins are encoded in the genes.

amino acid

sections of DNA (or RNA) that code for proteins

exons

are made of DNA; coded instructions that controls production of specific proteins, such as enzymes, structural proteins, oxygen-carrying proteins, etc. The expression of this takes place within transcription and translation. Does not build a protein directly.

gene

the A, C, G, and Ts--are strung together in a way that the cellular machinery, the ribosome, can read them and turn them into a protein. Each three nucleotides in a row count as a triplet and code for a single amino acid.

genetic code

basic building block of nucleic acids and small units in DNA; consist of a phosphate group, a 5-carbon sugar called deoxyribose, and a nitrogen base.

nucleotide

steps in transcription

DNA is copied into a complementary strand of mRNA. mRNA carries the code out of the nucleus. * RNA is made in 5-3 direction; DNA template is read in 3-5 direction. -Location: Inside the nucleus -Starts: DNA Ends: RNA 1) RNA polymerase binds to the DNA promoter and unzips the gene that needs to be copied. 2) RNA polymerase uses complementary base pairing rules on the RNA nucleotides ( A-U C-G) 3)Releases the completed mRNA molecule. 4) DNA zips back up and the mRNA leaves the nucleus and enters the cytoplasm.

predict a consequence for an error made during dna replication

DNA replication is a highly accurate process, but mistakes can occasionally occur as when a DNA polymerase inserts a wrong base. Uncorrected mistakes may sometimes lead to serious consequences, such as cancer.

Summarize the process of DNA replication

DNA replication is the process of making an identical copy of DNA in the nucleus. Occurs during the S phase of Interphase, and uses Enzyme Helicase, Primase, DNA polymerase, and DNA ligase to undergo the process. -Occurs in nucleus of the cell -Parent DNA makes 2 exact copies of DNA. Enzyme helicase unzips, rna primase adds 1 rna primer to leading and many rna primers to lagging strand. Lagging strand has OKAZAKI fragments. DNA polymerase continuously replicates on leading strand and discontinuously replication on lagging strand. It proofreads DNA ligase seals up the gaps in okazaki fragments

Transcribe the following strand of DNA to mRNA, and translate a sequence of amino acids from the mRNA: TACACCGGAGCGTTTATT

DNA: 3 TACACCGGAGCGTTTATT 5 mRNA: 5 AUGUGGCCUCGCAAAUAA 3codons: AUG UGG CCU CGC AAA UAA

Compare and contrast DNA and RNA

DNA: A-T C-G, double-stranded, Deoxyribose sugar, thymine RNA: A-U C-G, Single-Stranded, Ribose sugar, Uracil Both are nucleic acids that store information in the cell

differences between a strand of DNA, genes, and a chromosome.

DNA: genetic information found in the nucleus of a cell. GENES: a segment of DNA on a chromosome that codes for a genetic trait. CHROMOSOME: thread-like material that is tightly coiled with DNA and proteins called histones.

function of each enzyme in the process of DNA Replication.

Enzyme Helicase: unzips the DNA into 2 strands. Primase: -required for DNA synthesis -Makes short RNA primers.( short pieces of RNA that help get the DNA polymerase started). DNA Polymerase: only adds nucleotides to the free 3 prime end of the template strand. 5 prime to 3 prime direction 1ST FUNCTION: adds complementary nucleotides to the template strands (A-T C-G) -2ND FUNCTION: after all the nucleotides are added to complementary strand, RNA primer is removed and replaced with DNA. - 3RD FUNCTION: proofreads the strand before the backbone is finished (3rd function). DNA Ligase: " Seals" the gaps in DNA. -Connects DNA pieces by making phosphodiester bonds.

steps of translation

Interpreting/reading the mRNA message to make a protein. -Location: Cytoplasm/ Ribosome -Starts: mRNA Ends: Protein 1) mRNA attaches to the small subunit of the ribosome. 2) Ribosome reads the mRNA codons ( 3 mRNA nucleotides) ALWAYS in the 5 to 3 direction. Starts at AUG codon. 3) tRNA (transfer RNA) molecules act like taxis to pick up and drop off the amino acids that match with the current codon being read off the mRNA.- they also carry anticodons which base pair with the mRNA. 4) tRNA's continue to drop off amino acids, while the ribosome binds the amino acids together with peptide bonds. 5) When the "stop codon" is reached, the ribosome releases the completed protein.

difference between the leading strand and the lagging strand in DNA replication.

Leading Strand: -Is the new strand made toward the replication fork - Only in the 5 to 3 direction -Needs 1 RNA Primer -Replicates continuously Lagging Strand: - New strand synthesizes away from replication fork.- Replicated discontinuously. - Creates Okazaki fragments joined by DNA Ligase. - Needs many RNA Primers

copies the instructions in DNA and carries them to the ribosomes in the cytoplasm.

Messenger RNA

Explain, in detail, the structure of a DNA molecule.

The structure of a DNA molecule is a double helix that is made up of nucleotides that each include a phosphate group, a 5 carbon deoxyribose sugar, and a nitrogen base.

sequences of nucleotides that are complementary to codons. They are found in tRNAs, and allow the tRNAs to bring the correct amino acid in line with an mRNA during protein production.

anticodon

allows the DNA to be packed very tightly inside the cell; is composed of DNA and proteins.

chromosome

a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis. DNA and RNA molecules are written in a language of four nucleotides; meanwhile, the language of proteins includes 20 amino acids.

codon

short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections. Function: A building block for DNA synthesis of the lagging strand; are important for DNA synthesis because there is no 3' to 5' strand of DNA for the polymerase to use as a continuous template.

okazaki fragments

many amino acids connected by peptide bonds, which make up proteins, made during translation

polypeptide

The site of translation; the ribosome facilitates the orderly linking of amino acids into proteins. The cell must translate the base sequence of an mRNA molecule into the amino acid sequence of a protein. The cell uses information from mRNA to produce proteins. In the nucleus, DNA transcribes RNA. The RNA is sent to the cytoplasm in the form of mRNA. The mRNA attaches to a ribosome. As each codon of the mRNA molecule moves through the ribosome, the proper amino acid is brought into the ribosome by tRNA. The amino acids are lined up in the right order on the ribosome. The ribosome hitches the amino acids together with peptide bonds and proteins are made.

protein synthesis

information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). The newly formed mRNA copies of the gene then serve as blueprints for protein synthesis during the process of translation.

transcription

the base sequence of an mRNA is used to order and to join the amino acids in a protein. The three types of RNA participate in this essential protein-synthesizing pathway in all cells

translation