Unit 3 Flashcards
What are the 2 types of genetic chains
Deoxyribonucleic acid and ribonucleic acid
What monomers make DNA and RNA
Nucleotides
What are the three parts of nucleotide
- phosphate group PO4
- 5 carbon (Pentose) sugar either deoxyribose or ribose
- nitrogenous base
What are the 5 bases and where are they present
Adenine, cytosine, and Guanine (DNA+RNA)
Thymine (DNA)
Uracil (RNA)
What are purines
Adenine and guanine, have a double ring bond
What are pyrimidines
Thymine, uracil, and cytosine
Single ring bond
What are the base pairings
A with T 2 h bonds
C with G 3 h bonds
Purine is always with a pyramiding
How do the nucleotides string together
The sugar of one joins to the phosphate of another forming the sugar-phosphate backbone
The bases join together through H bonds
What shape does a DNA strand take
A double helix
Strands are in “Anti-Parallel” facing opposite directions
What are the 5’ and 3’ in Pentose sugar
The 5th and 3rd prime carbon in the sugar. Tells you which direction the Strand is facing
Why does a cell need to replicate DNA
When a cell divides it need 2 exact copies of the DNA for the new cells.
When does DNA replication occur
In the interphase
What is the first step of DNA replication
DNA Helicase unzips the molecule by breaking the H bonds at the replication fork
What is the second step of DNA replication
free floating nucleotides line up with complementary bases
New H bonds form and DNA polymerase runs down molecule double checking and sealing H bonds
Where are the new nucleotides found for dna replication
They are free floating in the nucleoplasm and originate from food and molecules
What is the third step of DNA replication
DNA lignes runs down the bases and bonds the sugar / phosphate backbone
What is the final step of DNA replication
2 identical DNA molecules are ready for the dividing call
Both are identical, any mistakes are mutations
They are semi conservative keeping 1/2 old and getting 1/2 new
What is Recombinant DNA
The use of various techniques and enzymes to recombine DNA from different organisms
What can we do with recombinant DNA
Take a gene from one species and insert it into the DNA of a different species where it can be expressed
What enzymes are use in recombinant DNA
Restriction enzymes
What are three possible used for Recombinant DNA
Protein production
Gene therapy
Transgenic organisms
What is protein production
Take a gene from one organism (like the human insulin gene) put it in a new organism (like E. coli bacteria) which can produce the protein for our use
What is gene therapy
The correction of non functional gene in individuals. A virus can be used to inject the correct gene into the cells of a patient to cure illnesses like cystic fibrosis
What are transgenic organisms
Organisms with a foreign gene inserted into them to give it features not possible through breeding
To make better plants and animals for agriculture
What are the two stages to protein synthesis
Transcription: (DNA code copy to mRNA)
Translation: (mRNA to make proteins @ ribosome)
What is unique about RNA
Single stranded
Found in nucleus and cytoplasm
Uracil
What are the 3 types of RNA
mRNA (messenger RNA)
rRNA (ribosomal RNA)
tRNA (transfer RNA)
What is messenger RNA
Takes message from DNA out of nucleus to a ribosome
Needs to be remade for every protein or enzyme
What ya ribosomal RNA
Made In nucleus and combined with proteins to make ribosomes “read” mRNA’s message 3 letters at a time to make amino acid chains and then proteins
What is transfer RNA
Transfer the correct amino acid to the ribosome to build the polypeptide chain
What is the first step of transcription
DNA helicase unzips and unwinds a section of DNA to expose one Gene (chromosome puff)
What is the second step of Transcription
Only one side of DNA is used to make a mRNA copy of the code. An enzyme RNA polymerase attaches to exposed DNA and complimentary base pairs make the code with RNA nucleotides
What is the start codon
AUG, methionine
What are the three stop codons
UAA
UAG
UGA
What is the first step in translation
Initiation - mRNA leaves the nucleus and Travels to a ribosome (rRNA making two subunits)
The ribosome reads the mRNA, looking for the start codon and looks into place
What is the second step In translation
Elongation - the ribosome “reads” the mRNA codons and “calls out” for the tRNA to bring the appropriate amino acids
If class for two tRNAs at a time and they lock in (codon to anticodon) side by side
The two amino acids join by peptide bonds
tRNA leaves and the ribosome moves on
What is an anticodon
Found on tRNA
3 bases complimentary to a specific codon
What is the last step in translation
Termination - when the ribosome reaches a stop codon it releases the mRNA, the new completed polypeptide (which will head to the Golgi), the mRNA will disintegrate, tRNA leaves, and ribosome comes apart
What are the 3 causes of mutations
Germinal
Somatic
Mutagens
What are germinal mutations
Can be passed on to offspring like hemophilia
What are somatic mutations
Body cell
Not inheritable
Ex cancers
What are mutagens
X-rays, radiation, chemicals, heavy metals, etc
What are chromosome mutations
A change in the physical piercing of a chromosome
Usually involves thousands of genes
Missing pieces
Extra pieces
Exchange of pieces
More detrimental
Many developmental disorders
What is translocation
Pieces of separate chromosomes are exchange
What is deletion
Pieces become missing
What is duplication
Extra pieces are copied and added
What is inversion
Pieces are flipped into reverse order
What is a gene
A segment of DNA in a chromosome that codes for one protein
The human genome has ~3 billion base pairs which are 10-15% genes
What was the first organism to have a genome sequenced
Haemophilus influerizae, a bacteria with 1.8 million base pairs
What are gene mutations
A change in the nucleotide sequence which affects 1 gene
What are the two types of frame shift mutations
Deletion and addition
They change all the following codons
Serious
What is a point mutation
Changes only one codon
Substitution
Less serious
What is deletion
One base is left out
What is addition
One base is added
What is substitution
Pieces are replaced with each other
How do mutations affect chemical reactions
Chemical reactions occur in pathways where one leads to another
If one enzyme in the pathway is nonfunctional then the pathway is interrupted and something like a blood clot will be prevent
