Biodiversity Flashcards
1
Q
Messeger RNA
A
- Made during transcription
- Carries genetic code from DNA to the ribosomes where its used to make protein during translation
- mRNA is a single polynucleotide strand
- In mRNA groups of three adjacent bases are called codons
2
Q
Transfer RNA
A
- Involved in translation
- Carries the amino acids that are used to make proteins to the ribosomes
- tRNA is a single polynucleotide strand folded into a clover
- Has hydrogen bonds to keep the clover shape
- tRNA molecules have a specific sequence of three bases at one end called an anticodon and an amino acid at the other end
3
Q
Transcription
A
- Enzyme called RNA polymerase attaches to the DNA
- Hydrogen bonds between two DNA strands break and it uncoils
- Bases become exposed and the sense strand becomes a template for mRNA
- RNA nucleotides pair up with specific bases on DNA and they are joined together by RNA polymerase
- Forming an mRNA molecule which moves out of the nucleus through a nuclear pore and attaches to a ribosome
4
Q
Translation
A
- The mRNA attaches to a ribosome
- tRNA has an anticodon that is complementary to the first codon on the mRNA so they attach and the amino acid it codes for is left behind
- More tRNA molecules attach to the codons in order on the mRNA
- The amino acids that are left behind are joined together by a peptide bond
- This produces a chain of linked amino acids called a polypeptide chain until there is a stop signal on the mRNA molecule
- The polypeptide chain folds into a protein
5
Q
Introns
A
- Part of the DNA that is non-coding
6
Q
Exons
A
- Part of the DNA that code for amino acids
7
Q
The Genetic Code
A
- Sequence of codons/ base triplets in mRNA which code for a specific amino acid
- Non-overlapping: each base sequence is read in order and only apart of one triplet
- Degenerate: more than one triplet combination codes for the same amino acid
- Start/stop signal: some triplets signal the start and stop production of mRNA
- Universal: same specific base triplets code for the same amino acids in all living things
8
Q
Eukaryotes Products of Transcription
A
- Introns and exons are both copies into mRNA during transcription
- mRNA strands containing introns and exons are called pre-mRNA
- Splicing occurs which removes the introns and joins the exons together to form the mRNA strand
9
Q
Prokaryotes Products Of Transcription
A
- mRNA is produced directly from DNA
- This is due to there being no introns present in prokaryotic DNA so splicing isn’t necessary
10
Q
Number Of Bases & Amino Acids
A
- Sometimes more bases are reported than there are amino acids
- Introns are present and these are non-coding sections/bases
- Stop/start codons don’t code for amino acids, instead they code for the start or end of protein production
11
Q
Genes & Alleles
A
- Genes can exist in many forms called an allele
- Orders of bases in each allele differ slightly so they code for different version of the same protein
12
Q
Classification
A
- Grouping together related organisms
- There are eight levels of groups used to classify organisms
- The groups are called taxa and each group is called a taxon
- Arranged in a hierarchy with the largest groups at the top and smallest at the bottom
13
Q
Taxonomy
A
- The science of classification, involves naming and dividing organisms into groups
14
Q
Hierarchy
A
- Groups within groups
- Without overlap; organisms only belong to one group at each level
- Down the hierarchy there are more groups at each level with fewer organisms in each group that are more closely related
15
Q
Levels of Classification
A
- Organisms ate first sorted into three domains
- Kindgom
- Phylum
- Class
- Order
- Family
- Genus
- Species
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