Bio 23 Section 9-10 Flashcards
What does DNA stand for?
Deoxyribonucleic acid
How many molecules (chromosomes) are in the nucleus of most human cells?
46 DNA molecules and they are about 2in in length
DNA is a polymer of?
Nucleotides
What does a nucleotide consist of?
A sugar group, a phosphate group, and a nitrogenous base
What are the nitrogen bases in DNA?
A T, C, G
What are the purines (double rings) of nitrogenous bases?
Adenine (A) and Guanine (G)
What are the pyrimidines (single rings) of nitrogenous bases?
Cytosine (C) Thymine (T) Uracil (U)
What are the nitrogenous bases in RNA?
A, C, G, U
DNA is represented by a?
Double helix
RNA is represented by a?
Single nucleotide chain.
How many RNAs are there?
Three
What are the names of the RNAs?
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
What sugar does DNA hold?
Deoxyribose (simple sugar)
What sugar does RNA hold?
Ribose sugar
What was the previous definition of a gene?
A segment of DNA that carries the code for a particular protein.
How many genes are in the human body?
About 20,000
What is the current definition of a gene?
An information-containing segment of DNA that codes for the production of a molecule of RNA that plays a role in synthesizing one or more proteins.
The amino acid sequence of a protein is determined by what?
Nucleotide sequence in the DNA.
How many sets of the 23 chromosomes come from each parent?
One
What is a genome?
It is all the DNA in one 23-chromosome set.
What is Genomics?
The study of the whole genome
How genes and noncoding DNA interact affects the structure and function of the organism.
A gene on average is how many bases long?
3,000 but can be up to 2.4 million bases long.
All humans are at least what percent genetically identical?
99.99%
The comination of single-nucleotide polymorphisms accounts for what?
All human genetic variations
What is a Base triplet?
The sequence of three DNA nucleotides that stand for one amino acid.
What is a Codon?
3-base sequence on mRNA.
What is the start codon?
AUG codes of methionine
What are the stop codons?
UAA, UGA, UAG
What cells do not contain identical genes?
Sex cells and some immune cells.
Where does transcription occur?
Nucleus
What is the process of protein synthesis?
DNA to PremRNA to mRNA to protein
In translation does mRNA code for proteins?
Yes
Where does translation occur?
Cytoplasm
What are the two types of Pre-mRNA?
Exons and Introns.
What are exons?
A segment of pre-mRNA that will export from the nucleus and translate into protein.
What are Introns?
Segments of pre-mRNA must be removed before translation.
Can one gene code for more than one protein?
Yes
What do chaperone proteins do? slide 35
They guide the folding of newly synthesized proteins
What are the three participants in translation?
mRNA, tRNA, and Ribosomes
what is the function of mRNA (Messenger RNA)
It carries code from the nucleus to the cytoplasm.
It has a protein cap that is a recognition site for the ribosome.
What is the function of tRNA Transfer RNA?
It delivers a single amino acid to the ribosome.
Contains an anticodon- a series of three nucleotides that are complementary to the mRNA codon.
What is the function of the Ribosomes?
Organelles that read the message and build a peptide chain.
Free in the cytosol, on rough ER, and on the nuclear envelope.
When the start codon (AUG) is reached what beings?
Protein synthesis.
What are the three steps in Translation?
Initiation
Elongation
Termination
What is Initiation?
It is the leader sequence on mRNA that binds to small ribosomal subunits and contains the AUG (methionine)
What is Elongation?
Is when The strand becomes longer.
What is Termination?
When the ribosome reaches the stop codon
Polyribosome?
When one mRNA is attached to multiple ribosomes
Can a cell have many mRNA molecules undergo simultaneous translation?
Yes
How many protein molecules can a cell produce every second?
100,000+
What is the job of Chaperone proteins?
They guide the folding of newly synthesized proteins
They help prevent improper associations between different proteins.
What are the names f the proteins that chaperones produce in response to heat or stress?
Stress proteins or heat-shock proteins
Proteins that are to be used in the cytosol are likely to be made on what?
Free ribosomes in the cytosol
Proteins that are destined for packaging onto lysosomes or secretion from the cell are assembled where and sent where?
Assembled on the Rough ER and sent to the Golgi complex fro packaging.
What are the four steps in DNA replication?
Unwinding
Unzipping
Building new strand
Repackaging
What does DNA unwind from?
Histones
What is a mutation?
Changes in the DNA structure due to replication errors or environmental factors
