Mix Flashcards
Nucleotide structure
Deoxyribose sugar, phosphate and base
Prokaryotes have ………. chromosomes and smaller ………
Single circular chromosomes
Circular plasmids
Eukaryotes have ………. in the nucleus which are …….
Linear chromosomes
Tightly coiled
How does dna replication occur?
DNA polymerase and primers
What does PCR do?
Amplify dna using complementary primers for specific target sequences
What are the three types of rna
mRNA tRNA and rrna
mRNA carries a copy of the nucleus from the nucleus to
The ribosome
Why does tRNA fold?
Due to complementary base pairing
RRNA and proteins form
The ribosome
RNA splicing forms what kind of mRNA transcript?
Mature
Introns of the ……are non coding and are joined together to form….
Primary transcript
Mature transcript
Translation begins and ends at where?
Starts at a start codon
Ends at stop codon
What bond holds amino acids together?
Peptide bonds
Amino acids are linked by peptide bonds to form what?
Polypeptide
Describe the shape of DNA molecule
Double Helix
Features of DNA
double helix shape Sugar phosphate backbones Antiparallel strands Hydrogen bonds link strands Complementary base pairing rules applied to nucleotides
Prokaryotes: Organisms Linear chromosomes Circular chromosomes Plasmids
Bacteria
Not present
In cytoplasm
Yes
Eukaryotes: Organism Linear chromosomes Circular chromosomes Plasmids
Animals
Within nucleus
Within mitochondria
No
Requirements for DNA replication
DNA templates Free dna nucleotides Primers DNA polymerase Source of energy (ATP)
Stages for replication in DNA
Double helix is unwound by DNA POLYMERASE (enzyme). The hydrogen bonds that connect the two strands are unzipped
Primers join
The process requires energy which is supplied by ATP which is produced by the cells respiration.
Why is DNA replication important?
It ensures that identical copies of genetic information of a species is passed on from cell to cell and from generation to generation
Requirements for PCR
DNA has to be amplified (copied) Primers Heat tolerant DNA polymerase Supply of nucleotides Ph buffer
Steps in PCR
heat mixture to 92-98 to get single strand of dna
Lower temp to 50-56 to allow primers to bind to DNA
Reheat to 72 for heat tolerant DNA polymerase to synthesise the new strand of DNA
Reheat to 90 so Dna becomes single stranded for the second time. Lower the temp and allow the primers to anneal and extend the primers
What is DNA polymerase
Enzyme that adds free complementary dna nucleotides during replication
What is ligase?
Enzyme that joins dna fragments to make the lagging strand
Enzymes
Speed up the rate of chemical reactions
Hormones
Chemical messengers in regulation
Antibodies
Defensive substances that give immunity against specific diseases
The differences between DNA and RNA
DNA nucleotides have deoxyribose sugar but RNA has ribose
DNA bases are adenine thymine guanine and cytosine. RNA has uracil instead of thymine
RNA is single stranded
What is mRNA, tRNA, rRNA
mRNA carries complementary copy of the genetic code from the dna in the nucleus to the ribosomes of the cytoplasm
tRNA carries specific amino acids to the ribosome to form polypeptide chains
Rrna is combined with proteins to make up the structure of ribosomes
Codon
Sequence of three bases of tRNA that specifies an amino acid
Exon
Sequences of dna that codes for a protein
Intron
Non coding sequence of DNA
Transcription
Copying of a DNA sequence to make a primary transcrip
Translation
Production of a polypeptide using sequences of mRNA
What are meristems
Region in a plant in which mitosis occurs
Stem cell
Cell that can divide and then differentiate in animals
What can be produced from stem cells?
Liver Blood Muscle Nerves More stem cells
Ethical issues of stem cells
Illegal trade
Stem cells being used eugenically
Is the presentation of suffering more important that the duty to preserve human life
Single gene mutations
Substitution
Insertion
Deletion
Chromosome mutations
Duplication
Deletion
Translocation
Inversion
Effects of chromosome mutation
Duplication: highly detrimental
Deletion: cri du chat syndrome evolves after the loss of part of chromosome 5
Translocation: can cause Down syndrome
Inversion: unable to produce gametes leading to infertility
Polyploidy
Possession of extra chromosomes
Splice site mutations
Mutation at a point where coding and non coding regions meet in a section of DNA
What is speciation
The evolution of two or more species from a common ancestor
Types of speciation
Allopatric- isolated by GEOLOGICAL barriers (mountains or oceans)
Sympatric- isolated by ecological barriers
Horizontal inheritance
Inheritance of genetic material within a generation
Vertical inheritance
Inheritance of genetic material from parents by offspring
Three domains of life
Archaea
Bacteria
Eukaryotes
Molecular clock
A graph showing differences in sequence data for protein against time
Phylogenetics
Study of evolutionary relatedness of species
Sequence data
Info concerning amino acid or nucleotide base sequencing
