Genetic Information, variation and relationship between organisms Flashcards
(19 cards)
DNA- Structure related to its function (7)
1) Stable due to numerous hydrogen bonds so can be passed on from generation to generation
2) Weak hydrogen bonds between strands are easily broken for DNA replication or protein synthesis
3) Large so can carry a lot of genetic information
4) base pairs are contained within the helix and held in place by the strong sugar-phosphate backbone
5) Complementary base pairs allows the synthesis of an identical daughter molecule
6) Strands so both can act as templates
7) Helical shape means that it can be coiled so compact for storage
DNA- Degenerate and Non-overlapping (2)
1) Degenerate: more than one base triplet for each amino acid
2) Non-overlapping: each base is apart of only one triplet
DNA- Comparing DNA and mRNA (7)
1) DNA double stranded/double helix and nRNA single-stranded
2) DNA very long and RNA short
3) Thymine in DNA and Uracil in RNA
4) Deoxyribose in DNA and ribose in RNA
5) DNA has base pairing and mRNA doesn’t
6) DNA has hydrogen bonding and mRNA doesn’t
7) DNA has introns and mRNA doesn’t
Comparing mRNA and tRNA (3)
1) mRNA is longer
2)mRNA is a straight molecule but tRNA is a folded molecule/clover leafed shaped molecule
3) mRNA doesn’t contain hydrogen bonds but tRNA has hydrogen bonds
Which two molecules are ribosomes made from? (2)
1) RNA/Ribonucleic acid
2) Proteins
Define the term exon
Base sequence coding for a polypeptide/sequence of amino acids
Name the protein associated with DNA
Histones
Differences between prokaryotic DNA and Eukaryotic DNA (5)
(eukaryotic v prokaryote)
1) Associated with histones v no histones
2) Linear v circular
3) No plasmids v plasmids
4) Introns v no introns
5) Longer v shorter
Transcription- Describe transcription (7)
1) DNA strands separate by breaking hydrogen bonds
2) Only one of the strands is used as a template
3) Complementary base pairing so A to U, T to A, C to G, G to C
4) RNA nucleotides joined by RNA polymerase
5) Forms phosphodiester bonds
6) Pre-mRNA is formed
7) Splicing removes the introns to form mRNA
Translation- Describe Translation (7)
1) mRNA binds to ribosome
2) Ribosome moves to start codon
3) Two codons/binding sites in ribosomes
4) Allows tRNA with anticodons to bind with codon on mRNA
5) tRNA brings specific amino acids
6) mRNA moves along to the next codon
7) Catalyses formation of peptide bonds between amino acids held by tRNA molecules
Translation- Role of Ribosomes (5)
1) mRNA binds to ribosome
2) Ribosome has two codons/binding sites
3) Allows tRNA with anticodons to bind
4) Catalyses formation of peptide bonds between amino acids
5) Moves along mRNA to the next codon
Translation- Role of tRNA (4)
1) Anticodon complementary to codon
2)Specific to Amino acid
3) Carried/ Transferred to ribosome
4) Correct sequence of amino acids along polypeptide
Describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule (3)
1) Condensation reaction
2) Between phosphate and deoxyribose
3) Catalysed by DNA deoxyribose
What is a gene?
A sequence of DNA nucleotides that code for a polypeptide
The genome is…
The complete set of genes in a cell
The proteome is…
The full number of different proteins the genome is able to code for
Meiosis- Causes of Variation (6)
1) Homologous chromosomes pair up
2) Chiasmata formed
3) Independent segregation
4) Maternal and paternal chromosomes are re-shuffled in any combination
5) Crossing over leads to exchange of parts of alleles
6) Both create new combinations of alleles
Meiosis- Process of Crossing Over (4)
1) Homologous pairs of chromosomes form a bivalent
2) Chiasmata form
3) Allele are exchanged
4) Producing new combinations of alleles
Describe how the process of meiosis results in haploid cells
1) DNA replication in interphase creates two identical chromatids
2) Meiosis has two nuclear divisions
3) First division, homologous pairs separate
4) Second division, sister chromatids separate
