Biology Week 3 Protein Functions Flashcards

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Questions and Answers

Which of the following are functions of proteins? (Select all that apply)

They provide structural support for many animal tissues. (correct)

They can store genetic information.

They play a key role in the contraction of muscles. (correct)

They transport ions and molecules across cell membranes. (correct)

Proteins are made up of one or more unbranched chains of?

amino acids

What describes the chemical structure of a typical amino acid?

A central carbon atom is bound to an amino group, carboxyl group, a side chain, and a hydrogen atom.

What type of bond forms between two amino acids during dehydration synthesis?

peptide bond Signup and view all the answers

Which characteristic of a protein determines its function?

shape Signup and view all the answers

Choose the functions of proteins in living cells. (Select all that apply)

They play a key role in moving materials within cells. Signup and view all the answers

Proteins are polymers made up of how many different amino acids?

20 Signup and view all the answers

What are the three major structural components of an amino acid?

Side chain (R), Amino group, Carboxyl group Signup and view all the answers

The structure of proteins is discussed in terms of how many levels?

4 Signup and view all the answers

When two amino acids are linked together, a peptide bond is formed between the _ group of one and the _ group of the other.

amino, carboxyl Signup and view all the answers

Which of the following determines the function of a protein molecule?

Its shape Signup and view all the answers

The structure of _____ is usually discussed in terms of a hierarchy of 4 levels.

proteins Signup and view all the answers

Match the following levels of protein organization with their definitions:

Primary = The linear sequence of amino acids Secondary = Repetitive folding patterns such as alpha helix and beta pleated sheet Tertiary = The overall 3-D shape of each polypeptide Quaternary = How two or more polypeptides interact to form a protein Signup and view all the answers

The covalent bond that joins two amino acids is called a _____ bond.

peptide Signup and view all the answers

How many polypeptides are present in a protein whose highest level of structure is tertiary structure?

1 polypeptide only Signup and view all the answers

What level of protein organization involves two or more polypeptide chains?

Quaternary Signup and view all the answers

The amino acid sequence of its polypeptides is called the _____ structure of a protein.

primary Signup and view all the answers

What is the primary structure of a protein?

The amino acid sequence of the polypeptides. Signup and view all the answers

Regarding polypeptides, the two basic types of _ structure are alpha _ and beta-pleated sheet.

secondary, helix Signup and view all the answers

Which type of interaction involves the formation of a covalent bond between two different amino acid side chains?

Disulfide bridge Signup and view all the answers

Select the disease type that could result from a deficiency in chaperone proteins.

A disease caused by improper folding of proteins. Signup and view all the answers

Which interactions help determine a protein's tertiary structure? (Select all that apply)

Ionic bonds Signup and view all the answers

Individual polypeptides within a protein are referred to as which of the following?

Subunits Signup and view all the answers

Diseases caused by the improper folding of proteins may be due to deficiencies in ____ proteins.

chaperone Signup and view all the answers

The tertiary structure of a protein is determined primarily by interactions involving which of the following?

The R groups of the amino acids Signup and view all the answers

Which best describes the relationship between temperature and enzyme activity?

Each enzyme has an optimum temperature where it functions best. Signup and view all the answers

If the interactions maintaining the 3-dimensional shape of a protein are disrupted and the polypeptide chains completely unfold, how is this protein described?

It is denatured. Signup and view all the answers

Which statements about the relationship between enzymes and environmental conditions are true? (Select all that apply)

Changing environmental conditions may alter the activity of enzymes. Signup and view all the answers

Protein denaturation may be caused by an increase in which of the following? (Select all that apply)

Ionic concentration Signup and view all the answers

Changes in a protein's environment can cause it to unfold and lose its shape in a process called?

Denaturation Signup and view all the answers

Which describes denatured proteins?

They are usually inactive. Signup and view all the answers

True or false: Protein structure is usually not affected by changes in the temperature, pH, or ionic concentration of the surrounding solution.

False Signup and view all the answers

Changes in a protein's shape can alter its ability to function or even cause it to become biologically?

inactive Signup and view all the answers

Study Notes

Functions of Proteins

Proteins play a crucial role in muscle contraction, transport of ions and molecules, providing structural support, and catalyzing biochemical reactions.
They are essential for moving materials within cells and transporting oxygen in vertebrate blood.
Proteins help the immune system recognize and eliminate foreign microbes and cancer cells.

Structure of Proteins

Proteins consist of unbranched chains of amino acids.
A typical amino acid has a central carbon atom bound to an amino group, a carboxyl group, a side chain (R), and a hydrogen atom.
The structure of proteins is discussed in four hierarchical levels: primary, secondary, tertiary, and quaternary.

Amino Acids and Bonds

20 different amino acids serve as the building blocks for proteins.
A peptide bond forms between the amino group of one amino acid and the carboxyl group of another during dehydration synthesis.

Protein Organization

The primary structure refers to the linear sequence of amino acids.
Secondary structure includes folding patterns like α-helixes and β-pleated sheets.
Tertiary structure refers to the overall 3D shape of a polypeptide.
Quaternary structure involves the interaction of two or more polypeptide chains.

Protein Interactions

Hydrophobic exclusion drives proteins into their tertiary structure.
Disulfide bridges, ionic bonds, and hydrogen bonds contribute to the stability of the tertiary structure.
Chaperone proteins assist in proper protein folding; deficiencies can lead to diseases from misfolding.

Denaturation of Proteins

Denaturation occurs when a protein's 3D shape is disrupted, causing it to unfold and lose functionality.
Factors leading to denaturation include increased temperature, changes in ionic concentration, and alterations in pH.
Denatured proteins are typically inactive.

Enzyme Activity

Each enzyme has an optimal temperature for peak performance.
Enzymes are sensitive to environmental changes, which can affect their structure and activity.
Maintaining favorable conditions is vital for optimal enzyme functioning.

Additional Facts

Individual polypeptide chains within a protein are referred to as subunits.
Protein structure is significantly influenced by the properties of the R groups of amino acids.

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Description

Test your knowledge on the functions and structure of proteins with these flashcards. This quiz covers key roles of proteins in muscles, transport, support, and catalysis. Perfect for reinforcing your understanding in Week 3 of biology studies.