DNA is the chemical that determines inherited characteristics and it contains vast amounts of information in the form of genetic code
What is the structure of a DNA molecule?
helical
double helix
pleated sheet
What three components is a nucleotide of DNA made up of?
a variable group
a phosphate group
a deoxyribose sugar
an organic base (C, T, A or G)
a hydrocarbon
The single ring bases are?
C
G
A
T
The double ring bases are?
DNA is made up of two strands of polynucleotides. How do the nucleotides join to become polynucleotides?
Hydrogen bonds
Condensation Reaction between phosphate group of one nucleotide and deoxyribose of another.
Polar attraction
Which base does cytosine pair with?
adenine
thymine
guanine
What base does thymine pair with?
adenine?
guanine?
cytosine?
The organic bases form the structural backbone of DNA
What is the function of DNA?
To pass genetic information from cell to cell and generation to generation.
To provide energy for the cell.
To make organic bases.
How is the DNA molecule adapted to carry out its functions? (4 points)
It is very stable and can pass from generation to generation without changing.
It is flexible so can be easily changed.
It's two strands are only joined with H bonds which allow them to separate for DNA replication.
The two strands are joined with H bonds that are strong and prevent the strands from separating.
The molecule is extremely large so carries an immense amount of genetic information.
The structural backbone protects the genetic information from corruption.
The molecule is very small so lots of them can fit in a small space.
What is a gene?
A sequence of DNA bases that determines a polypeptide (a sequence of amino acids).
A molecule that contains all the genetic information of a cell.
A substance made up of DNA
What are introns?
Sections of DNA that don't code for amino acids.
Amino acids.
Three bases that code for an amino acid.
The triplet code can be read in either direction of the DNA strand
The start of a sequence of the triplet code is always the same: the amino acid 'methionine'.
Stop codes are triplet codes that don't code for an amino acid, but the end of a polypeptide chain.
The triplet code is only specific to humans.
Prokaryotic cells don't have chromosomes as their DNA molecules are smaller and not associated with protein molecules
Chromosomes are visible all the time.
The DNA helix is wound around proteins to hold it in position.
A chromosome contains a single molecule of DNA.
How many chromosomes do humans have?
78
46
23
48
A homologous pair of chromosomes determine the same genetic characteristics.
What are different forms of a gene called?
alleles
chromosomes
haploid cells