DNA and RNA ( genetics intro) Flashcards
species
a group of organisms that have the ability to produce fertile offspring
variation
differences between members of the same species
What is acquired varation and list examples
they are learned or developed
eg.scars, language, sport
what are Inheirited vairations and list examples
controlled by genes and can be passed on to offspring
eg. eye colour, skin colour, freckles
heredity
passing on of traits from parent to offspring by means of genes
Gene
a section of dna on a chromosome that causes a protein to be produced
chromosome
thread like structure made up of DNA and protein
Non-coding DNA
DNA that does not cause a protein to be made
Gene expression/ Coding DNA
when a protein is made
Genetic code
refers to the instructions contain in a gene that tells a cell how to make a specific protein
what does DNA stand for
deoxyribonucleic acid
What is a nucleotide composed of
a Sugar, nitrogenous base , phosphate
what is a polynucleotide
many nucleotides joined together
What are the nitogenous bases in DNA
Adnine, thymine, Guamine, Cytosine
what is the sugar in DNA?
deocyribose
What is the stucture of DNA
DNA is composed of two polynucleotide chains, held together by hydogen bonds.
Base pairing in DNA is always complemtary
Why is base peiring in DNA always complentary?
adnine always bonds to thymine
guamine always bonds to cytosine.
A purine always bonds to a pyrimidine
Which nitrogenous bases are in purines
Guanine
adnine
which notrogenous bases are in pyrimidines
cytosine
thymine
uracil
What is the shape of DNA?
double helix structure (complimentary base pairs forming horizontal bars,
Phosphate and sugar forming vertical bars)
eukaryotic
has a nucleus and contains membrane bound organelles
name structures in an eukaryotic cell where DNA is found
nucleus, mitochondria, chloroplasts
where is DNA in chromosomes
wrapped around histones
What is a sub unit of DNA
nucleotide
DNA profiling
method of making a unique pattern of bands from the DNA of an individual, this can be compared to other DNA samples
Describe in detail the steps of DNA profiling
DNA isolation
extracting DNA from cells (non coding DNA is used)
Cutting
DNA is cut into fragments by restriction enzymes
separation
gel electrophoresis separated the fragments based on their size, the small pieces travel futher
pattern analysis and comparison
gel stained and viewed under UV light (DNA pattern can be compared to another pattern)
Genetic screening
testing DNA for the presence or absence of a paticular gene/mutated gene
give applications of genetic screening
adult acreening is used to identify carriers of diseases such as cystic fibrosis
foetal screening is used to test if a fetus has a genetic disorder
DNA replication
how DNA makes a copy of itself
when does DNA replication occour in the cell cycle?
Interphase
Describe in detail DNA replication
DNA Helix unwindes. DNA helicase (enzyme) separates the strands by breaking the hydrogen bonds.
The exposed bases act as a template to produce new strands.
New nucleotides connect to the exposed bases on the old strands.
DNA polymerase joins the DNA nucleotides together to build the new stands.each DNA strands consists of one old and one new strand.
When replication is finished, DNA rewinds and recoils
What is meant by semi-conservative in DNA?
the new, freshly replicated DNA contains a stand from the orginal DNA and a new strand
Name an anabolic enzyme
DNA polymerase
What is the significance of DNA replication
allows for cell continuty
allows for traits to be passed from parents to offspring
what is cell continunity
all cell arise from pre exising cells
what does RNA stand for
ribonucleic acid
Comparare DNA and RNA
DNA
double stranded
sugar is deoxyribose
nitogenous bases: adenine, thymine, guanine, cytosine
found in nucleus, mitochondria, chloroplast
RNA
Single stranded
sugar is ribose
nitrogenous bases are adnine, uracil, gianine, cytosine
found in nucleus, ribosome and chloroplast
Name the three types of RNA and where they are located
T RNA (transfer RNA) cytoplasm
R RNA ( Ribosomal RNA) ribisome
M RNA (messenger RNA) nucleus
describe the role of tRNA
carries an amino acid to the ribosome, binds with the mRNA
describe the role of rRNA
attaches the mRNA to ribosome and holds it in place
describe the role of m RNA
gets the genetic code from DNA and carries it to the ribisome and attaches itself to the ribisome
Codon
sequence of three bases in DNA or RNA that codes for one amino acid
Name the three types of codon
start codon, amino acid codon, stop codon
what type of bonds hold amino acid chains together?
peptide bonds
Where in the cell is protien made?
ribosomes
name the two steps involved in protein synthesis
transcription, translation
What is transcription
makeing m RNA using DNA as a template, process occours in nucleus
describe the process of transcription in detaill
DNA unwindes and splits. using the DNA starnd as a tempate,RNA nucleotides bond with the exposed bases .RNA polymerase joins the RNA nucleotides together to form m RNA. m RNA leaves through the nuclear pores
What is tranlation
making a protein using the code in the messenger RNA
describe the process of translation
Occours on the ribosome in cytoplasm
mRNA is bonded to the ribosome by rRNA.
base pairs of m RNA attract complentary base pairs. these complentary base pairs come in groups of threes called an anticodon. there is a start codon, an amino acid codon and a stop codon.the transfer RNA carries an specific amino acid to the ribosome. A string of amino acids are formed by peptide bonds bonds assembles.
protein is folded to activate it
what is an anticodon
a sequence of 3 bases on t RNA which is complementary to a codon in mRNA
Describe the procedure of isolating DNA from plant tissue (Kiwi)
-chop kiwi (breaks open cell walls and increases SA)
-add chopped kiwi, salt (clumps the DNA together), washing up liquid (dissolves cell membrane) into beaker.
-water bath for 15mins @ 60C ( Denatures enzymes that would break down DNA, no more than 15min as this would break down the DNA)
- place in ice bath for 5min ( stops breakdown of DNA)
-Blend mixture for 3sec (breakes down cell walls and membranes, not any longer or else DNA will break down)
-filter mixure in new beaker ( DNA passes through, cell fragments removed)
-transfer to test tube.
- add 3 drops of protease to filtraten( breakes down protein surrounding DNA)
-add freezing cold ethanol down one side of test tube at an angle ( ethanol speparates DNA from filtrate, DNA insoluble in colf ethanol)
-DNA percipitated and it is collectede using a glass rod.
decribe the apperance of isolating DNA from plant tissue (Kiwi)
white stringy clumps of DNA
