Unit 10 Biology Flashcards
Nucleotide
The subunits that make up DNA
The three parts that make a nucleotide
Phosphate group, Five-carbon sugar, and Nitrogen-containing bases
Where are Five-carbon sugar (deoxyribose) and phosphate group founded?
These two are found in all nucleotides - make the backbone of the double helix
What are the nitrogen-containing base?
(4 types)
*Adenine and Guanine (A and G)
*Thymine and Cytosine (T and C)
The purines are
Adenine and Guanine
The pyrimidines are
Thymine and Cytosine
The structure of a DNA molecule
*Double helix-like a ladder
*Sugar and phosphate make the back bone
*Base make the rungs
What did Chargraff show?
Showed that amount of A=T and C=G
What did Wilkins and Franklin do?
*Used X-Ray diffraction photographs to show DNA
*Showed tightly composed of two chains of nucleotides
What did Watson and Crick do?
Built a model of DNA which showed the helix shape
What are the base pairing rules?
*Adenine always pairs with Thymine (A=T or T=A)
*Cytosine always pairs with Guanine (C=G or G=C)
The sequence of bases on one strand determines the?
The sequence of bases on the other strand
The process of DNA replication (3 steps)
- Two original strands of DNA separate
- DNA polymerases add complementary nucleotides to each strand
- Two DNA molecules form that are identical to the original DNA molecules
What happens when two original strands of DNA separate?
*DNA helicases break the H bonds (Hydrogen bonds)
*The separated strands are called replication forks
DNA polymerases add complementary nucleotides to each strands using?
*the use of base pairing rules
How errors are corrected during DNA replication?
The DNA polymerases have a proofreading role
The proofreading role description (process)
*The bases have to be correctly paired for the polymerase to move to the next base.
*It can backtrack if it is wrong
*Removes the incorrect nucleotide and replaces it with the correct one
*Reduces error to 1 in 1 billion
Replication fork
*A separated strand of DNA
*Replication doesn’t begin at one end of a DNA
The number of replication forks in prokaryotic cells
*It has a circular strand of DNA
*2 sets of replication
The number of replication forks in eukaryotic cells
*Each chromosome has 1 long strand of DNA
*multiple replication forks working together
What is RNA
*Single strand
*It contains instructions for making a protein
The bases of RNA
The bases are Adenine, Guanine, Cytosine, and Uracil
The five-carbon sugar in RNA is called
It’s called ribose which has 1 more oxygen
What is DNA
Double strand
The five-carbon sugar in DNA is called
The sugar is called deoxyribose
The three types of RNA
*Messenger RNA (mRNA),
*Transfer RNA (tRNA)
*Ribosomal RNA (rRNA)
Messenger RNA (mRNA)
*writes the instructions from DNA
–Takes them to the ribosome
Where does mRNA happens (occurs at)
Occurs in the nucleus
Ribosomal RNA (rRNA)
Reads the codons on the mRNA
Where is rRNA located
Located at the ribosome
Transfer RNA (tRNA)
Transfers the amino acids using anticodons
The process of transcription (4 steps)
- RNA polymerase binds to the gene’s promoter
- The two DNA strands unwind and separate
- Complementary RNA nucleotides are added, which eventually reaches a stop codon. After the DNA closes back
- mRNA leaves the nucleus, headed to the ribosome
Transcription
*RNA polymerase is used
*RNA nucleotides are linked
*RNA molecule is made
*Only one part of one strand is used as a template
Replication
*DNA polymerase is used
*DNA nucleotides are linked
*DNA molecule is made
*Both DNA strands are used as templates
Now that the instructions are scripted from DNA in the nucleus, _____
they have to be translated
Translation
Process by which an mRNA strand leaves the nucleus and travels to the ribosome to provide instructions to the production of a protein
Codons
instructions on the mRNA are written as a series of three-nucleotide sequences on RNA
What does each codon correspond to
Each codon corresponds to an amino acid or the start or stop signal for translation
Genetic code
*the amino acids, start or stop signal that each codon represents
–All things contain DNA - the codon code is universal
–With few exceptions, it is the same in all organisms
–Called “nearly universal”
Anticodon
*The complementary 3 bases to the mRNA codon
–They are carried by tRNA
The process of translation (7 steps)
- Begins when mRNA reaches the ribosome, which uses a start codon to begin
- tRNA uses anticodons to know which amino acid to bring
- Peptide bonds attach the amino acid’s together
- tRNA detaches and leaves behind the amino acid
- tRNA brings another amino acid and attaches it
- It leaves the amino acid
- Steps 2-6 are repeated until it reaches a stop codon
