Genetics Flashcards
Explain the process of translation.
Translation is the process by which amino acids are produced using mRNA as a template.
Describe the structure of mRNA and how it is related to its function.
mRNA is a single-stranded molecule that carries genetic information from DNA to ribosomes for protein synthesis.
Summarise the Hershey and Chase experiment.
The Hershey and Chase experiment demonstrated that DNA is the genetic material by using radioactive labeling to track DNA and protein in viruses.
Compare and contrast DNA in eukaryotes with that of prokaryotes, mitochondria and chloroplasts.
Eukaryotic DNA is linear and found in the nucleus, while prokaryotic DNA is circular and located in the cytoplasm. Mitochondria and chloroplasts have their own circular DNA.
Explain what the terms genome and proteome mean.
The genome is the complete set of genetic material in an organism, while the proteome is the entire set of proteins expressed by a genome.
Explain what is meant by the terms chromosome and gene.
A chromosome is a structure made of DNA that contains many genes, which are segments of DNA that code for proteins.
Explain the process of transcription in prokaryotes.
Transcription in prokaryotes involves the synthesis of RNA from a DNA template, occurring in the cytoplasm.
Explain the process of transcription and splicing in eukaryotes, linking this to knowledge of introns.
In eukaryotes, transcription occurs in the nucleus, producing pre-mRNA, which is then spliced to remove introns and form mature mRNA.
Explain the specific roles of ribosomes, ATP and tRNA in translation.
Ribosomes facilitate the assembly of amino acids into proteins, ATP provides energy for the process, and tRNA transports specific amino acids to the ribosome.
What is a gene?
A gene is a segment of DNA that encodes a specific protein or functional RNA.
What is a base triplet? How many are there?
A base triplet is a sequence of three nucleotides that codes for a specific amino acid. There are 64 possible base triplets.
Label the following: Sugar-phosphate backbone, Phosphodiester bonds, Hydrogen bonds, Excasidic bonds, Nucleotide, Base Pairing.
The sugar-phosphate backbone consists of alternating sugar and phosphate groups, phosphodiester bonds link nucleotides, hydrogen bonds form between base pairs, and nucleotides are the building blocks of DNA.
Describe the structure of tRNA and how it is related to its function.
tRNA has a cloverleaf structure with an anticodon at one end and an amino acid attachment site at the other, allowing it to bring specific amino acids to the ribosome during translation.
How does DNA result in a polypeptide chain (protein)?
DNA is transcribed into mRNA, which is then translated by ribosomes into a polypeptide chain, forming a protein.
What are the characteristics of DNA?
DNA is described as degenerate, universal, and non-overlapping.
What is the function of meiosis?
The function of meiosis is to produce gametes for sexual reproduction.
What type of reproduction is meiosis?
Sexual
Does meiosis produce genetically identical cells?
No, cells produced through meiosis have genetic diversity
How many daughter cells does meiosis produce compared to mitosis?
Meiosis produces 4 genetically different cells, whereas mitosis produces 2 clones.
How many daughter cells does meiosis produce compared to mitosis?
Meiosis produces 4 genetically different cells, whereas mitosis produces 2 clones.
What processes in meiosis cause genetic variation?
Crossing over, random combination, independent segregation
What is crossing over?
Crossing over is a process in meiosis where a chromatid breaks during meiosis and joins its homologous chromatid so its alleles are exchanged.
What are the steps in meiosis?
Interphase, prophase I, metaphase I, Anaphase I, telophase I 2 CELLS PRODUCED
prophase II, metaphase II, anaphase II, Telophase II, 4 CELLS PRODUCED prophase
What is a mutation and what causes them to happen?
A gene mutation is a change in the DNA base sequence.
Mutations occur spontaneously if DNA is misread during DNA replication. Ultraviolet or ionising radiation, chemicals and viruses can increase the rate of mutations. These are known as mutagens.
Describe what a mutagenic agent is, and identify some possible mutagenic agents.
A mutagenic agent can increase the rate of mutations, for example UV radiation, chemicals and viruses.
How can you calculate the number of different gametes with differing paternal and maternal chromosome combinations?
(2n)
N is number of chromosome pairs, so in humans n is 23.
How can you calculate the number of different zygotes with differing paternal and maternal chromosome combinations?
(2n)2
Explain what a non-disjunction event is and how they occur.
A non disjunction event is when homologous chromosomes fail to seperate in meiosis, resulting in gametes with missing or extra chromosomes.
Compare and contrast gene and chromosomal mutations.
Gene mutations change only a single gene, but chromosomal mutations change an entire chromosome.
What is meant by genetic diversity?
The differences in traits between individuals of a species.
What is allele frequency?
The proportion of a specific allele in a population.
What are selection pressures?
External factors that affect an organisms ability to survive and reproduce. Eg disease, predation, climate.
What are the advantages of genetic diversity?
Helps species adapt to their surroundings, contributes to a range of foods being produced, disease resistance.
