Biol 1107 test 1 Flashcards
DNA Molecules include what four nucleotides?
Adenine, Guanine, Cytosine, and Thymine
What makes up a nucleotide?
a phosphate group, a 5 carbon sugar and a nitrogenous base
What two nucleotides are purines
Adenine and Guanine
What two nucleotides are pyrimdines
Cytosine and Thymine
What is a purine?
Large two carbon ringed nucleotides
What is a pyrimidine?
a small one carbon ring nucleotide
The nitrogenous base is binded to what end of the five carbon sugar?
the 1’ end
The phosphate group is binded to what end of the 5 carbon sugar
the 5’ end
How is a strand of DNA formed?
when the phosphate groups bind to the 3’ end of another nucleotide
What are the complementary base pairs?
A-T and G-C
How are complimentary based paired bound to each other?
With hydrogen bonds
Name three ways RNA is different from DNA
1.) Rna has ribose as its sugar
2.) RNA sugar has a hydroxyl group at the 2’ of the sugar ring which makes it less stable
3.) RNA used Uracil instead of Thymine
4.) RNA is single-stranded
5.) RNA can fold back on itself to create base pairs
What are the three types of RNA?
1.) mRNA: messenger rna
2.) tRNA: transfer rna
3.) rRNA: ribosomal rna
What is the central dogma?
the flow of information in organisms (storing/using info)
What is a protein
a chain (polymer) of amino acids
What is an amino acid composed of?
- an amino group
- an R group
- an carboxyl group
Non-polar molecules are…
hydrophobic
polar molecules are….
hydrophillic
negatively charged molecules form what bonds?
ionin bonds
Why do amino acids R groups stick out?
to react with other molecules and other R groups
DNA—–>________——->RNA——–>__________——–>Proteins
transcription and translation
RNA polymerase always read from what side
3’ to 5’ side
Can either strand of DNA be used for transcription?
Yes
Proteins can be…..
structural, regulatory, contractile or protective
How many amino acids are commonly found in proteins?
20
The amino acids R groups chemical properties determine….
the properties of the amino acid
How do you form a protein?
By connecting the amino acids through covalent bonds (peptide bonds)
What is a polypeptide?
a long chain of amino acids
What is a peptide?
short chain of amino acids
Tell me about polypeptide ends
polypeptide ends have an N terminal and non-binded carboxyl group
What are the different protein structures?
primary, secondary, tertiary, and quaternary
What is the primary structure of a protein?
A sequence of amino acids chains
What is the secondary structure of a protein?
folding itself into an alpha helix of beta pleated shape
What is the tertiary structure of a protein?
the 3-d structure
What is the quaternary structure of a protein?
two protein changed folded together
what is it called when all DNA is present in an organism?
the genome
What is a chromosome?
a single large DNA molecule
What are the regions in a chromosome information is stored to make RNA and proteins
a gene
What is a promoter?
the beginning of a gene
What is the end of a gene called?
the terminator
What is the region in between the promoter and the terminator called that codes for RNA and proteins
the coding region
What is gene expression?
extracting and using info from genes
What are the steps of transcription?
1.) initiation
2.) elongation
3.) termination
Describe the initiation step of TRANSCRIPTION
A transcription bubble is formed in between the strands of DNA where RNA polymerase will start coding at the start of the promoter. RNA polymerase only starts from the 3’ end
Explain elongation in TRANSCRIPTION
RNA polymerase goes down the template strand coding for one complementary rna nucleotide at a time
Explain the termination step of TRANSCRIPTION
Transcription stops when RNA polymerase reaches the terminator of the gene and the new rna strand will look like the non template strand except it has uracil
What is pre-mRNA
the mrna molecules produced by transcription
What characterizes a pre-mrna molecule?
1.) it has a nucleotide cap added to the 5’ ends so it wont degrade
2.) it has a poly-A-tail added to the 3’ end
What is mrna splicing?
the removal of introns from the mrna carried out by a splicesome
What is alternative splicing?
the taking out of exons to code for different proteins or genes expressed
When are proteins produced?
in the translation phase
What does transfer RNA do?
interprets information carried by mrna and brings the correct amino acids to the growing protein
What is a ribosome?
a large complex of proteins and ribosomal rna that is organized into large and small subunits
-the small subunits binds to trna to bring mrna and trna together
What are the phases of translation?
1.) initiation
2.) elongation
3.) termination
Describe initiation for TRANSLATION
the small subunit of ribosome binds to 5’ end of mrna which is recognized by the trna that carries the amino acid methionine (aka start codon)
Describe the elongation process in TRANSLATION
- the large subunit binds to the small subunit
- the p-site, a-site and e-site
What is a point mutation?
a change in a small number of nucleotides
What is a silent mutation?
when a nucleotide is changed but it doesn’t change the amino acid of protein produced
What is a missense mutation
when a nucleotide is changed and codes for a different amino acid/ protein
What is a nonsense mutation?
when a nucleotide is changed and creates a stop codon
What is frameshift mutation?
When an extra nucleotide is added or a nucleotide is deleted from a sequence
What marks the 5’ end?
a non-binded phosphate group
What marks the 3’ end
a sugar that is not bonded
What are constitutive genes
genes that are continuously expressed
What are conditional genes?
genes that are only expressed when needed (ex: insulin and glucagon)
What are transcription factors
proteins that recognize regions of DNA that activate or terminate a gene
