Mechanisms Of Inheritance & Biotech. Flashcards
What is DNA
Deoxyribonucleic acid (a polymer). DNA is the biological molecule of inheritance.
What shape is DNA in?
A double helix
What is DNA made up of?
Sugars - sides
Phosphate - sides
Bases (nitrogens) - rung
What are the 4 bases
Guanine
Cytosine
Thymine
Adenine
Which bases are purines and which are pyrimidines
Adenine & Guanine are purines (2 rings)
Thymine and Cytosine are pyrimidines (1 ring)
How are nucleotides connected to one another?
By covalent bonds between phosphate and sugar.
What is DNA replication
The copying of DNA before mitosis and meiosis
Where does DNA replication occur
In the nucleus during interphase just before prophase
What are the 4 enzymes that help DNA replication occur
Helical, DNA Polymerase, Primase, and Ligase
What does Helicase do
Unwinds and unzips by breaking the hydrogen bonds between bases
What does DNA Polymerase do
Builds the new DNA strand
What does the Primase do
initializes the entire process and sets a path for POLYMERASE to follow
What does Ligase do?
Glues the Okazaki fragments on the lagging strand
What is unzipping?
When the Helicase breaks the hydrogen bond forming a replication fork
What is the first step of DNA Replication
The origin is discovered and the strand is unwound (by the helicase) forming a replication fork
What is step two in DNA Replication
SSB (single stranded binding) proteins bind to each of the DNA sides to keep it unwound
What is step 3 in DNA Replication
Primase forms a primer on both sides of the unzipped parent DNA
What is the 4th step in DNA Replication
DNA Polymerase recognize the primer and uses free nucleotides t build the DNA strand by using the parent code
What is the 5th step of DNA Replication
Covalent bonds are formed between phosphates and sugars
Note: DNA is anti parallel, meaning……
Each strand is built differently. One strand is leading and one is lagging, therefore it is built in small fragments.
Which strand of DNA is leading and which strand is lagging
The strand with the number of carbons going from 5’ to 3’ is lagging, and the one going from 3’to 5’ is leading
What is the 6th step of DNA Replication
DNA polymerase reads the DNA 3’ to 5’ (building 5’ to 3’)
What is the 7th and final step of DNA Replication
Ligase joins the Okazaki Fragments on the lagging side (5 to 3)
What is RNA
It stands for Ribonucleic Acid, and is a bio molecule made of ribonucleotides
DNA vs. RNA
DNA RNA
——————————-)——————————-
- Deoxyribonucleic acid ) - Ribonucleic acid
- Codes for traits. ) - used in protein synthesis
- Double stranded. ) - single stranded
(twisted & coiled). )
- Found in nucleus ) - Found in nucleus & cytoplasm
- sugar is deoxyribose ) - sugar is ribose
- one type. ) - three types
What bases is RNA made of
Adenine
Uracil
Guanine
Cytosine
What are the 3 types of RNA
Messenger RNA (mRNA) which carries the instructions from the nucleus to the cytoplasm Ribosomal RNA (rRNA) and transfer RNA (tRNA) which are both involved in the process of ordering the amino acids to make the protein.
What is the 1st step in transcription
DNA is transcribed into a small message to be carried to a ribosome (by a mRNA)
What is the 2nd step in transcription
RNA polymerase ( an enzyme ) is used to “read” the message by “matching” the DNA code w. RNA bases
What is the 3rd & final step in transcription
The mRNA is transported out of the nucleus, to find a ribosome in the cytoplasm
What is the 1st step in translation
In the cytoplasm, mRNA moves to a ribosome made of rRNA where the protein is assembled
What is the 2nd step in translation
tRNA carries amino acids according to its anticodon, while mRNA holds the codons in the cytoplasm
What are chromosomal mutations
Chromosomal mutations involve changes in the number or structure of chromosomes
What are the 4 types of Chromosomal mutations
1) Deletion
2) Duplication
3) Inversion
4) Translocation
What is deletion
A mutation that involves the loss of all of part of a chromosome
What is Inversion
A mutation that reverses the direction of parts of a chromosome
What is duplication
A mutation that produces an extra copy f all or part of a chromosome
What is translocation
A mutation where one part of a chromosome breaks off and attaches to another
What are gene mutations
Mutations that involve changes n one or a few nucleotides
What are the 3 types of gene mutations
1) Substitution
2) Deletion
3) Insertion
What is substitution
A mutation where a single nucleotide is replaced or substituted
What is Deletion
A mutation similar to insertion, it shifts the reading frame of a genetic message and can change all of the amino acids after that mutation
What is insertion
A mutation where a single nucleotide is inserted into the DNA sequence causing a frameshift to occur, leading to all the amino acids after to be changed
What is recombinant DNA
DNA produced by combining DNA from different sources
What is gene therapy
When cloned genes are used to modify a human
What is a clone
An organism with genetically identical cells produced from a single cell
How do you create a clone
You take and grow a single cell that is genetically identical to the adult organism until it becomes an entirely new individual that is genetically identical to the owner of then original cell
Why are identical twins considered clones
The 1st and 2nd cells of the embryo separated and each became a complete individual
What are 3 reasons that people clone genes
1) To produce a large quantity of the genes protein product ex//insulin
2) To learn how a cloned gene codes for a particular protein
3) To use the genes to alter the phenotypes of other organisms in a beneficial way
What is a transgenic organism
An organism that contains genes from other organisms
How are transgenic organisms created
By inserting recombinant DNA into the genome of a host organism
What did franklin do
She produced the X-ray crystallography pictures of DNA
What did Fredrick Meischer do
He isolated the chemicals that made up white blood cells, which he called nuclien
What did McClintock do
She showed that chromosomal crossovers happen in corn chromosomes, and later discovered that x-rays could cause translocations, inversions, deletions, and ring chromosomes in corn
What did Avery do
He discovered transformation in bacteria, and proved cell fragments of dead, disease-causing bacteria could still cause pneumonia when allowed to come in contact with harmless bacteria
What did Hershey and Chase do
They studied bacrophages (a type of virus that attacks bacteria) and discovered that viral DNA had the info to produce more viruses
What did Crick do
Correctly proposed the structure of DNA, as well as ran the Human Genome Project from 1988 to 1992, and made the cold spring harbor lab
