DNA and genetics Flashcards
what does the dna structure look like?
double helix/twisted ladder shape
what are nucleotides?
The basic structural unit of DNA, consisting of a deoxyribose sugar, a phosphate and a nitrogen base
what are the base pairs?
T & A
C & G
A & T
G & C
how many hydrogen bonds are there when thymine and adenine bond?
2
how many hydrogen bonds are there when cytosine and guanine bond?
3
how many chromosomes and pairs are there in every cell?
46 chromosomes and 23 pairs
what do chromosomes consist of?
segments of dna known as genes
what are the 2 basic functions of dna?
- carry genetic information for inheritance
2. coding for amino acids to produce proteins
what is the process of copying dna called? what is it?
- this process is called dna replication
- to do this strands of the double helix must separate/zip
- the bases of the exposed strands pair up with free nucleotides forming new strand
what is a specific characteristic of dna replication that must be correct?
every cell must have identical dna to the original body cell
what does dna and rna stand for?
deoxyribonucleic acid & ribonucleic acid
what does protein synthesis do?
- holds instructions for every protein
- process of making proteins in the cell
- proteins are made up of amino acids
where do we get our supply of amino acids from? how many are there?
From the food we eat & 20 amino acids total
what is a group of three bases on dna stand called?
Codon = codes for 1 amino acid
what is copied into rna and why?
dna cannot leave the nucleus, so it has to be copied into rna which is only single stranded and small enough to leave the nucleus through the nuclear pores
where does protein synthesis happen?
ribosomes
what do the ribosomes do?
reads the rna in groups of 3 bases and signals for the matching amino acid
what does the order of the bases determine?
order of amino acids in the protein
what is mRNA & tRNA
mRNA is transcripted from dna & tRNA is translated from mRNA - amino acids attached to it
what is an organelle?
a membranous structure within a cell, specialised for a particular function
what is a chromosome?
A rod like structure that contains dna, which makes up the genes of an individual
what is a gene?
The factor that determines an inherited characteristic, located in the chromosomes
what is a trait?
an inherited feature of an organism
what is evolution?
the gradual change in the characteristics of a species over a period of time
what is natural selection?
the process by which species becomes better adapted to its environment
