RNA and Protein Synthesis Flashcards
What is the role of DNA in genetic material?
DNA contains a code that living cells can read, understand, and express.
What are the four nucleotides that make up DNA?
The four nucleotides are adenine (A), thymine (T), cytosine (C), and guanine (G).
What role does RNA play in relation to DNA?
RNA helps to put the genetic code into action by directing the production of proteins.
What are the structural differences between RNA and DNA?
RNA uses ribose sugar, is generally single-stranded, and contains uracil instead of thymine.
What is the function of genes?
Genes contain coded DNA instructions that tell cells how to build proteins.
What is transcription?
Transcription is the process of copying a base sequence from DNA into RNA.
What is the role of RNA polymerase?
RNA polymerase carries out transcription by producing complementary RNA molecules.
What are introns?
Introns are portions of pre-mRNA that are cut out and discarded before the RNA can go into action.
What is a codon?
A codon is a three-base sequence in mRNA that specifies a single amino acid.
How many possible codons are there in the genetic code?
There are 64 possible three-base codons in the genetic code.
What is a start codon?
The start codon is AUG, which initiates protein synthesis.
What is the role of ribosomes in protein synthesis?
Ribosomes assemble amino acids into polypeptide chains using the sequence of codons in mRNA.
What is the function of messenger RNA (mRNA)?
mRNA carries copies of instructions from the nucleus to ribosomes in the cytoplasm.
What is the function of transfer RNA (tRNA)?
tRNA carries amino acids to the ribosome and matches them to the coded mRNA message.
What is the significance of the TATA box in eukaryotic gene regulation?
The TATA box helps position RNA polymerase by marking a point just before the beginning of a gene.
What is the lac operon?
The lac operon is a cluster of genes in E. coli that must be turned on together to break down lactose.
How does the lac repressor function?
The lac repressor binds to the operator region to prevent transcription of the lac genes when lactose is not present.
What is the role of transcription factors in gene regulation?
Transcription factors help regulate gene expression by opening chromatin or blocking access to certain genes.
What are homeotic genes?
Homeotic genes are master control genes that regulate the identities of body parts in an embryo.
Who was the first to show that a specific group of genes controls body part identities in fruit fly embryos?
American biologist Edward B. Lewis.
What happens if one of the homeotic genes is changed?
A body part like an antenna might be changed into a leg.
What are homeotic genes?
A set of master control genes that regulates organs developing in specific body parts.
What is the homeobox?
A very similar 180-base DNA sequence shared by homeotic genes.
What do homeobox genes code for?
Transcription factors that activate other genes important in cell development and differentiation.
What are Hox genes?
A group of homeobox genes in flies that determine the identities of each segment of a fly’s body.
How are Hox genes arranged?
In the exact order in which they are expressed, from anterior to posterior.
What determines the basic body structure in fruit flies?
A series of Hox genes along a chromosome.
Do mice have Hox genes?
Yes, mice have similar genes on four different chromosomes.
Do clusters of Hox genes exist in other animals?
Yes, including humans.
What is the role of nucleosomes in gene regulation?
Nuclear DNA is coiled around nucleosomes to form chromatin, affecting gene expression.
How do chemical marks influence chromatin structure?
They determine how compact chromatin is in a given region of DNA.
What are epigenetic marks?
Chemical marks on chromatin that influence gene expression without changing DNA base sequences.
What is an example of environmental impact on gene expression?
The coloring of the coat of a Himalayan rabbit.
What was observed in Dutch children born post-WWII?
They had higher rates of obesity, diabetes, and cardiovascular disease than their parents.
What happens to the fur color of Himalayan rabbits at different temperatures?
At temperatures between 15°C and 25°C, the gene produces black fur; above 30°C, the gene is inactive and the rabbit is white.
What are mutations?
Heritable changes in genetic information caused by mistakes in DNA copying.
What are point mutations?
Mutations that change a single base pair in the DNA sequence.
What is a silent mutation?
A point mutation that does not affect the amino acid sequence.
What is a missense mutation?
A mutation that changes the amino acid specified by a codon.
What is a nonsense mutation?
A mutation that creates a stop codon, resulting in incomplete protein synthesis.
What are insertions and deletions?
Mutations where bases are added or removed from the DNA sequence.
What are chromosomal mutations?
Mutations that involve changes in the number or structure of chromosomes.
What are the four types of chromosomal mutations?
Deletion, duplication, inversion, and translocation.
What can cause mutations?
Errors in genetic processes and mutagens.
What are mutagens?
Chemical or physical agents that can cause mutations.
