Protein Synthesis Flashcards

Questions and Answers

What is the Central Dogma?

The process of extracting the genetic code from DNA to make mRNA and then make proteins from the mRNA.

What type of sugar is present in RNA?

Deoxyribose

Ribose (correct)

What is the difference in the number of strands between DNA and RNA?

1 strand (correct)

2 strands (correct)

Which nitrogenous bases are found in RNA?

A, C, G, U Signup and view all the answers

What does mRNA stand for?

Messenger RNA Signup and view all the answers

What is the function of Ribosomal RNA (rRNA)?

Makes up the organelle ribosomes where proteins are assembled. Signup and view all the answers

What does Transfer RNA (tRNA) do?

Transfers amino acids to the ribosome as coded for in mRNA. Signup and view all the answers

What is a promoter?

A region in the DNA molecule that signals the start of transcription. Signup and view all the answers

What is the mRNA cap made of?

Guanine Signup and view all the answers

What is the purpose of the Poly-A tail?

Protects the important part of mRNA from enzymes. Signup and view all the answers

How many ribosomal subunits are there?

One small and one large Signup and view all the answers

What does initiation refer to in the context of protein synthesis?

The anticodon that pairs with AUG is referred to as the 'initiator'. Signup and view all the answers

What happens during transfer RNA in translation?

The tRNA with anticodon binds to mRNA and delivers the corresponding amino acid. Signup and view all the answers

How does the ribosome function during translation?

The ribosome joins amino acids and moves along the mRNA to bind new tRNA molecules. Signup and view all the answers

What occurs when the ribosome reaches a stop codon?

The process continues until the ribosome reaches one of the three stop codons, resulting in a growing polypeptide chain. Signup and view all the answers

How many codons are there?

64 Signup and view all the answers

How many amino acids are there?

20 Signup and view all the answers

What does having multiple ribosomes translating mRNA simultaneously allow the cell to do?

Quickly create many copies of the required polypeptide. Signup and view all the answers

What is a polysome?

A complex formed when multiple ribosomes are translating the same mRNA into proteins. Signup and view all the answers

What is a mutation?

An error that results in an incorrect DNA sequence during DNA replication. Signup and view all the answers

What are gene mutations?

Involve one to several nucleotides Signup and view all the answers

What do chromosome mutations involve?

Changes in the number or structure of chromosomes Signup and view all the answers

What is a substitution mutation?

A mutation in which a single base is replaced, potentially altering the gene product. Signup and view all the answers

What is an insertion mutation?

A mutation in which one or more nucleotides are added to a gene. Signup and view all the answers

What is a deletion mutation?

A mutation in which one or more pairs of nucleotides are removed from a gene. Signup and view all the answers

Study Notes

Central Dogma

Describes the flow of genetic information from DNA to RNA to protein synthesis.
Involves transcription (DNA to mRNA) and translation (mRNA to protein).

Differences between DNA and RNA

Type of Sugar: DNA contains deoxyribose; RNA contains ribose.
Number of Strands: DNA is double-stranded; RNA is single-stranded.
Nitrogenous Bases: RNA has A, C, G, U (uracil); DNA has A, T, C, G.

Types of RNA

Messenger RNA (mRNA): Carries genetic instructions from DNA to ribosomes for protein synthesis.
Ribosomal RNA (rRNA): Combines with proteins to form ribosomes, the site of protein assembly.
Transfer RNA (tRNA): Transfers specific amino acids to ribosomes, matching anticodons with codons in mRNA.

Key Components in Transcription & Translation

Promoter: A DNA region that indicates where transcription starts.
mRNA Cap: A guanine modification at the 5' end that assists ribosome binding.
Poly-A Tail: A stretch of adenine nucleotides that protects mRNA from degradation.

Ribosome Structure

Composed of two subunits: one small and one large, facilitating protein synthesis.

Initiation of Translation

Begins at the start codon AUG, with the corresponding tRNA bringing methionine as the first amino acid.

Polypeptide Assembly

The ribosome facilitates the joining of amino acids, releasing tRNA to continue adding new amino acids from mRNA.
Process continues until a stop codon is reached, resulting in a polypeptide.

Steps of Protein Synthesis

DNA provides the template for mRNA formation.
mRNA undergoes processing and carries codons.
mRNA interacts with ribosomes in the cytoplasm.
tRNA matches anticodons to mRNA codons, delivering amino acids.
Peptide chains are formed through complementary base pairing and transferred between tRNAs.

Codons and Amino Acids

There are 64 possible codons.
20 different amino acids are used to build proteins.

Polysomes

Formation involves multiple ribosomes simultaneously translating the same mRNA, enabling rapid protein production.

Mutations

Defined as errors in DNA replication, resulting in a change in the DNA sequence.
Gene Mutations: Affect one or several nucleotides; include substitution, insertion, and deletion.
Chromosome Mutations: Involve changes in chromosome number or structure.

Types of Mutations

Substitution Mutation: A single base is replaced, potentially altering the gene product.
Insertion Mutation: One or more nucleotides are added to a gene.
Deletion Mutation: One or more nucleotide pairs are removed from a gene.

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Description

Explore the key concepts of protein synthesis with these flashcards. Learn about the Central Dogma, differences between DNA and RNA, and essential terms in the process. Perfect for students looking to reinforce their understanding of molecular biology.