is the passing on of genetic information from one generation to the next through reproduction
are sequences of DNA that contain a code of instructions for a specific trait
-a human cell contains many thousands of different genes, located on chromosomes, in its nucleus
-the traits inherited by an individual can be determined from one pare of genes or by several pairs of genes
-some gene pairs can influence more than just one trait
-some traits are observable, while others are not (examples: hair or eye color, ability to produce insulin, or types of receptors on cell membranes)
share all genes from one parent (identical/clones)
contain half their genetic code from one parent and half from the other, making them similar but NOT identical
allows for offspring with high variation
contain the genetic code for all organisms
is an organic molecule made of many small subunits called nucleotides (monomers)
-double helix molecule
each subunit contains...
a sugar, phosphate, and a nitrogenous base
4 nitrogenous bases
A,T,G and C (Adrenine, Thymine, Guanine and Cytostine)
A and T, G and C
-sequence of bases in a DNA molecule forms a coded message
DNA must be able to...
replicate or copy, its coded instructions
DNA bases are held by...
weak hydrogen bonds with may be broken to split into DNA into two single strands
single stranded DNA becomes...
a template for a new DNA molecule to be made
new DNA molecules are made by...
attaching matching base pairs of DNA to each template
two identical copies of the cell's genetic information
after DNA is replicated..
the cell divides to form two offspring cells, or daughter cells, each containing identical copies of DNA (mitosis)
single stranded, contains U instead of T, for uracil
-carry out most of the cells
-can be enzymes, hormones, antibodies, or make up parts of cell organelles
-the DNA code of gene is read in the nucleus and a messenger molecule is created (messenger RNA)
-the message travels to a ribosome in the cytoplasm
move specific amino acids to the ribosome, which are strung together to make a protein (transfer RNA)
the order of amino acids is determined by the DNA code
amino acids -> shape -> function
an alteration in a sequence of DNA
-change the normal message carried by the gene, causing a defect
- they are random
-affect the synthesis of proteins, which causes malfunctions in the cell. EX.) sickle cell anemia is caused by a substitution in the cell
-can cause cell death
mutations are due to...
insertion, detection, or substitution
if a cell survives a mutation...
the changed instructions will be passed on to all cells coming from in
for mutations to be inherited by offspring (sexual reproduction)...
they can only be in sex cells, only sex mutations in sex cells can be inherited
going from DNA to mRNA
going from mRNA to protein
-every body cell contains a complete set of identical genetic instructions
-cells have selective activation of only the genes necessary for that cell
- the environment can also affect the expression of genes
a new technology used to alter the genetic instructions of organisms
applying technology to biology, has been around for thousands of years
types of genetic engineering
selective breeding and gene manipulation
producing domestic animals and new variations of plants with desirable traits
-animals are breed to contain less fat
-fruits to be larger, sweeter, and longer lasting
organisms have been genetically engineered to possess certain traits
-flowers resistant to bugs
-bacteria that feed on chemicals in oil spills
-bacteria that produce HGH and insulin
-plants resistant to herbicides
how does gene manipulation happen?
special enzymes (restriction enzymes) cut DNA at specific sequences, which allows the DNA to be spliced or inserted, into a new organism
-organisms will make proteins that express the new trait, and pass it on to their offspring
technique used to separate DNA