DNA AND INHERITANCE Flashcards
Why is DNA IMPORTANT?
Determines our Characteristics
What are the names of the pairs in every human body cell/
Homologous pairs (23 chromosomes)
Structure of DNA
2 polynucleotide strands
Joined by nitrogenous bases
Coiled round in a double helix
Is DNA a polynucleotide?
Polynucleotide
What types of Bond holds the Bases together?
Hydrogen Bonds
What determines the shape of protein?
Sequence of bases determines the order of amino acids.
The sequence of bases determines the order of amino acids
The sequence of amino acids detrmines the shape of the protein
Use of tRNA?
In the cytoplasm, amino acids become attached to transfer RNA (tRNA) molecules which unlike mRNA have a clover shape. Each tRNA is specific for one amino acid
Each tRNA molecule has a sequence of three bases called an anticodon. These are complementary base pair to codons on the mRNA molecule.
Number of Polynucleotide Strands in DNA mRNA and tRNA
2-DNA
1-mRNA
1-tRNA
Shape of DNA, mRNA and tRNA
DNA- Double Helix
mRNA- Single Stranded straight chain molecule
tRNA- Clover Shape
Sugars in DNA, mRNA and tRNA
DNA- Deoxyribose
mRNA- Ribose
tRNA- Ribose
Three Bases Called
DNA, mRNA, tRNA
DNA- Triplets
mRNA- Codons
tRNA- Anticodons
Meiosis vs Mitosis?
Mitosis –> Body Cells
Meiosis –> To make gametes
Mitosis –> Chromosomes replicate themselves
Meiosis –> Chromosomes replicate and then mix up some genes
Mitosis –> 2 daughter cells are produced
Meiosis –> 4 daughter cells are produced
Describe Meiosis
Parent cell replicates DNA Chromosomes move to centre of cell and line up Recombination of genes Move towards poles (along spindles) Cell divides Chromosomes line up again Cells divide again Four haploid daughter cells are made
Protein Synthesis?
Part of the DNA double helix unwinds and unzips so the two strand seperate
Template STrand
Bases are exposed along the template strand
Complementary RNA nucleotides line up along the template strand
DNA zips up again
Forms an mRNA molecule
This mRNA levaes the nucleus and enter the cytoplasm
This is known as Translation and happens in the Nucleus
MRNA molecule attaches to ribosome
first tRNA anticodon binds to start codon on mRNA strand
Another tRNA anticodon binds to the second codon on the mRNA strand
A bond forms between 2 amino acids
first TRNA Molecule is released
More tRNA molecules arrive and add their amino acids to the chain, forming a protein
At the end of the mRNA molecule there ia stop codon and the mRNA is released
Role of tRNA?
Carries specific amino acids to the ribosomes to make proteins for transalation
