DNA and inheritance Flashcards
describe the structure and function of DNA
6 Marks
two long chains
alternating sugar and phosphate
connected by bases
twisted to form double helix
four types of bases:
Adenine, Thymine (A-T)
Cytosine, Guanine (C-G)
complementary base pairs. A-T and C-G
the order of bases form a code for making proteins
each triplet code identifies as a particular amino acid
amino acids are linked together to form proteins
what are the 4 letters that represent bases in DNA
A
T
C
G
describe the paring rules in DNA
Adenine pairs with Thymine
(A pairs with T)
Cytosine pairs with Guanine
(C pairs with G)
name the 4 base in DNA
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
how does the sequence of DNA affect the protein made in protein synthesis
DNA is triplet code where 3 bases code for one amino acid and the order of amino acids determine the protein produced
what is genetic profiling
A method of comparing DNA by cutting it into small pieces which are then separated into bands and then compared
what is genetic profiling
A method of comparing DNA by cutting it into fragments and comparing the fragments with each other
give 3 uses of genetic profiling
paternity testing (working out who is the biological parent of a child)
forensic identification (matching a criminal to DNA left at a crime scene)
matching an organisms DNA to classify it / comparing species for classification purposes
give benefits of genetic profiling
it can help to catch criminals
used to to identify the presence of certain genes which may be associated with a particular disease
what are ethical concerns surrounding genetic profiling
ownership issues
privacy
insurance problems
embryonic screening leading to abortion
what is a gene
a section of DNA that codes for a protein
a section of DNA that determines inherited characteristics
genes have different forms called alleles found in pairs
what are alleles
different versions of the same genes
what is a chromosome
tightly packed DNA
found in pairs int the nucleus
what are gametes
gametes are sex cells (sperm or eggs)
what is a dominant allele
an allele which when present in the heterozygous condition expresses itself in the phenotype
wat is a recessive allele
a version of a gene where two copies are needed for it to be expressed
what is meant by the term homozygous
when an organism has two copies of the same allele (two recessive or two dominant)
e.g AA or aa
what is meant by the term heterozygous
both alleles are different (one dominant and one recessive)
e.g Aa
what is the genotype
all the alleles in a organism
what is the phenotype
the visible characteristics
what is the F1 generation
the first offspring produced when organisms are bred together
what is the F2 generation
the offspring produced when two offspring (F1 generation organisms) are bred together
what is selfing
when gametes from the same parent fuse (e.g when pollen from a plant lands on the stigma of the same plant)
what is genetic engineering
altering the genome of an organism
what are the advantages of genetically modified crops
better crop yields
food will last longer and taste better
give the disadvantages of genetically modified crops
the new genes can easily spread to other plants in the environment
long term effects of genetically modified crops on health are unknown
what do the bands in genetic profiling show
the similarities between two DNA samples
what are the male and female genotypes
male = XX female = XY
what is genetic modification
genetic modification transfers genes between organisms
what are the benefits of genetic modification
crops can be herbicide resistant
crops can be genetically modified to be resistant to insect pests or to disease (increasing crop yield)
