Biology Chapter 10: Gene Expression

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Questions and Answers

What are the two main steps involved in gene expression?

Transcription and Duplication

Replication and Translation

Translation and Codon Matching

Transcription and Translation (correct)

Which type of RNA carries the information that codes for the amino acid sequence?

Messenger RNA (mRNA) (correct)

Transfer RNA (tRNA)

Nuclear RNA (nRNA)

Ribosomal RNA (rRNA)

What distinguishes RNA from DNA?

RNA is double-stranded

RNA contains thymine instead of uracil

RNA does not contain nucleotides

RNA includes ribose sugar instead of deoxyribose (correct)

How many codons are known to code for amino acids?

61 Signup and view all the answers

Which role does transfer RNA (tRNA) play during translation?

It matches codons on mRNA with anticodons Signup and view all the answers

What are the building blocks of proteins?

Amino acids Signup and view all the answers

What is a codon?

A group of three nucleotides coding for one amino acid Signup and view all the answers

How are amino acids linked during translation?

By peptide bonds Signup and view all the answers

What is the primary reason sickle cells are less effective at carrying oxygen?

They have an abnormally shaped hemoglobin. Signup and view all the answers

What genetic alteration leads to sickle cell disease?

An alteration in just one amino acid. Signup and view all the answers

Who provided evidence for the link between genes and protein structure in sickle cell disease?

Vernon Ingram Signup and view all the answers

Which term describes a person with insufficient hemoglobin levels in their red blood cells?

Anemic Signup and view all the answers

How can a change in protein structure be caused at the genetic level?

By a change in one nucleotide in a sequence. Signup and view all the answers

What characteristic shape do sickle cells resemble?

Commas Signup and view all the answers

Which of the following statements about hemoglobin in sickle cell disease is correct?

HbA is normal hemoglobin while HbS is abnormal. Signup and view all the answers

What function do red blood cells (RBCs) primarily serve in the body?

They transport oxygen to organs. Signup and view all the answers

Study Notes

Chapter 10: How Genes Work

The process by which genes are transcribed into RNA and translated to make proteins is called gene expression
Nucleotides are the building blocks of proteins leading to traits/phenotypes

Gene Expression Steps

Transcription: The first step, converting DNA information into RNA information. An mRNA copy of the gene is made in the nucleus.
Translation: The second step, converting RNA information into amino acid order in a protein. Amino acids are linked together at the ribosome to create the protein encoded by the mRNA.

Transcription

RNA is produced to create a blueprint for protein production
RNA differs from DNA:
- Uses ribose instead of deoxyribose
- Uses uracil instead of thymine
- Is single-stranded
Three major types of RNA are needed for translation:
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
All RNA is produced via transcription
Transcription begins when RNA polymerase binds to the promoter
An mRNA molecule is produced as RNA polymerase moves down the template strand of DNA
Transcription ends when RNA polymerase reads through the terminator

RNA Produced During Transcription

Transfer RNA (tRNA): Transports correct amino acids to the ribosome, pairs with mRNA codons revealed in the mRNA
Messenger RNA (mRNA): Specifies order of amino acids in a protein, using three-base codons
Ribosomal RNA (rRNA): Main component of ribosomes; assists in making covalent bonds linking amino acids

Translation

Translation is the process that converts the information in RNA into amino acid sequences
Three types of RNA have specific roles in translation:
- Messenger RNA (mRNA) contains the information for amino acid sequence, read in groups of three nucleotides called codons.
- Transfer RNA (tRNA) has a group of three nucleotides (anticodon) at one end that match with the mRNA codon, and an amino acid attachment site at the other end
- Ribosomal RNA (rRNA) forms ribosomes and provides a location for amino acid connections
Translation begins when mRNA binds to a ribosome
A first tRNA molecule carrying the amino acid methionine binds to the start codon
As the ribosome moves one codon at a time, tRNA molecules bind to mRNA, allowing the ribosome to link the amino acids in the correct order.
When the ribosome reaches a stop codon, the mRNA and the completed amino acid chain separate from the ribosome.

The Genetic Code

Genetic code is the information in DNA
Nucleotides are read in groups of three (codons)
Each codon codes for only one specific amino acid
Organisms on Earth use the same codons to code for the same amino acids
61 codons code for 20 amino acids
Many amino acids are coded for by two or more codons

Sickle Cell Disease

Sickle cell disease occurs when red blood cells have an abnormally shaped hemoglobin, causing cells to be sickle-shaped
Red blood cells (RBCs) are responsible for carrying oxygen to the body's organs.
Hemoglobin is a protein in RBCs that carries oxygen.
A person deficient in hemoglobin is considered anemic; their RBCs can't carry oxygen efficiently
Sickle cell disease results from inheriting a gene that codes for abnormal hemoglobin (HbS)
Normal hemoglobin is called HbA
The disease occurs because of a change/mutation in only one nucleotide which leads to a change in the amino acid sequence of the protein, resulting in a dysfunctional protein.

Additional Notes

Proteins are composed of amino acids in a specific sequence. A change in just one amino acid can cause a significant change in the protein.
Amino acids link together forming a shape that is stable and most important to the chemically stable protein shape, allowing the protein to work correctly. The shape of a protein is crucial for its function.

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Description

Explore the intricate processes of gene expression in Chapter 10. This quiz covers transcription and translation, highlighting the roles of different types of RNA. Test your understanding of how genes are converted into proteins and the significance of nucleotides in determining traits.