DNA & Genetics Flashcards
What does DNA stand for?
Deoxyribonucleic Acid
What are the only cells without a full set of DNA?
Sex cells as they combine together to make a full set
Red blood cells have them but lose them as they are produced
How many chromosomes does each nucleus have?
46 with 23 pairs
Why makes people have down’s syndrome?
Because they have an extra chromosome in each cell
Who and when was the structure of DNA discovered?
Watson & Crick discovered it in 1953
What does the nucleus contain?
Chromosomes that are made up of a string of genes.
What are genes?
Segments of DNA. They have the instructions for one protein. Many work together to form on characteristic.
What are the strands in DNA made of.
Deoxyribose and phosphorus with phosphorus connecting the deoxyribose together.
What are the four nitrogenous bases in DNA and which ones are connected to each other?
Adenine & thymine (connect together)
Cytosine & guanine (connect together)
What is a nucleotide?
They are molecules in DNA made up of a base, sugar, and phosphorus. Together, they make a polynucleotide.
What is replication?
Replication is a process that copies DNA before mytosis (cell division) and during synthesis (making phase)
Ensures next generation of cells are identical
1) Begins with unwinding of DNA strand with an enzyme called DNA helicase which breaks the hydrogen bonds. Each half is a template for a new DNA strand.
2) Creation of two new DNA. This is done by adding free nucleotides to the original templates. Enzyme called DNA polymerase does this by creating new hydrogen bonds between the nitrogenous bases. I follows the base pair rule (A & T, C & G) and forms a complementary stand on each template strand. This makes two new DNA.
What is transcription?
When gene switched on, enzyme called RNA polymerose attaches to start of it
Enzyme moves along the DNA, making a strand of RNA with free bases in the nucleus
DNA code determines witch order the bases are added to the messenger RNA
In RNA, instead of thymine, there is uracile
Before being used as a template, it’s processed (removing & adding sections of RNA)
What is inside of a nucleus?
A genome that is split between 23 pairs of chromosomes
Each contain a long strand of DNA packaged around histones. DNA contains instructions for making proteins
What is translation?
Messenger RNA leaves nucleus into the cytoplasm of cell
Protein factories called ribosomes bind to RNA
Ribosome reads RNA code to produce chain of amino acids (20 types)
Transfer RNA molecules carry carry amino acids to ribosome
Transfer RNA has three bases and connects to three corresponding ones
As the bases in the transfer RNA are read, it delivers its corresponding amino acid which adds up to a chain of amino acids
This chain folds to form a protein
