Proteins and Their Structures
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary characteristic that distinguishes eukaryotic cells from prokaryotic cells?

  • Presence of ribosomes
  • Enclosed nucleus containing DNA (correct)
  • Presence of plasma membrane
  • Lack of a membrane-bound nucleus

Which organelle in eukaryotic cells is primarily involved in protein synthesis?

  • Nucleus
  • Ribosomes (correct)
  • Plasma membrane
  • Smooth endoplasmic reticulum

What function does the smooth endoplasmic reticulum serve in eukaryotic cells?

  • Protein synthesis
  • Regulation of cell division
  • Lipid synthesis and detoxification (correct)
  • Storage of genetic material

In which eukaryotic cell type would you expect to find a high activity of smooth endoplasmic reticulum?

<p>Adrenal cortex cells (B)</p> Signup and view all the answers

What is the main role of the golgi apparatus in eukaryotic cells?

<p>Processing and packaging proteins (D)</p> Signup and view all the answers

What component of the eukaryotic cell acts as a selective barrier regulating entry and exit of substances?

<p>Plasma membrane (A)</p> Signup and view all the answers

Where does ribosomal assembly occur in eukaryotic cells?

<p>Nucleolus (A)</p> Signup and view all the answers

Which of the following statements is true regarding the nucleus in eukaryotic cells?

<p>It contains genetic information (D)</p> Signup and view all the answers

What is the primary function of mitochondria in a cell?

<p>Site for cellular respiration and ATP production (D)</p> Signup and view all the answers

Which of the following statements accurately describes lysosomes?

<p>They contain enzymes for digestion and recycling of cellular components. (A)</p> Signup and view all the answers

What role do microfilaments play in the cell structure?

<p>They are involved in intracellular movements. (A)</p> Signup and view all the answers

What is a key characteristic of the endoplasmic reticulum?

<p>It is involved in protein transport and glycosylation. (B)</p> Signup and view all the answers

Which of the following is true regarding cytosol?

<p>It is an aqueous matrix where metabolic processes occur. (C)</p> Signup and view all the answers

How do mitochondria maintain their own replication?

<p>They reproduce by binary fission. (B)</p> Signup and view all the answers

What distinguishes intermediate filaments from microfilaments and microtubules?

<p>They provide mechanical support under stress. (D)</p> Signup and view all the answers

What are the enzymes found in mitochondria responsible for?

<p>The citric acid cycle and oxidative phosphorylation. (A)</p> Signup and view all the answers

What percentage of total body water is typically found intracellularly?

<p>60% (B)</p> Signup and view all the answers

Which group is likely to have the highest percentage of body water?

<p>Children (A)</p> Signup and view all the answers

What characteristic of water allows it to dissolve most organic and inorganic molecules?

<p>Its dipolar structure (D)</p> Signup and view all the answers

How does water act in relation to pH maintenance?

<p>It can act as both an acid and a base. (D)</p> Signup and view all the answers

What defines the dielectric constant of a material?

<p>Its resistance to electric field formation (C)</p> Signup and view all the answers

Which group tends to have the lowest percentage of body water?

<p>Older adults (D)</p> Signup and view all the answers

What role does water play as a chemical reactant?

<p>It acts as a nucleophile in chemical reactions. (A)</p> Signup and view all the answers

Why do obese individuals generally have a lower percentage of body water?

<p>Because fat contains minimal water. (D)</p> Signup and view all the answers

What is the main purpose of homogenization in cellular studies?

<p>To disrupt the cell and liberate its constituents (A)</p> Signup and view all the answers

Which method is NOT a part of the isolation of biomolecules and organelles?

<p>Sonication (B)</p> Signup and view all the answers

What is the content of the final supernatant after centrifugation?

<p>Cytosol (C)</p> Signup and view all the answers

Which of the following is a method to determine the structure of biomolecules?

<p>Mass spectrometry (C)</p> Signup and view all the answers

In centrifugation, what is produced at successively greater speeds?

<p>Pellet and supernatant (D)</p> Signup and view all the answers

Which of the following components is NOT associated with a peroxisome?

<p>Lactate Dehydrogenase (B)</p> Signup and view all the answers

What is the correct sequence of the fractions produced during centrifugation?

<p>Nuclear fraction, mitochondrial fraction, microsomal fraction (A)</p> Signup and view all the answers

What role do marker enzymes play in the analysis of organelle purity?

<p>To measure the purity of organelle fractions (A)</p> Signup and view all the answers

What effect does water have on the attraction between charged particles?

<p>It decreases the attraction because of its high dielectric constant. (C)</p> Signup and view all the answers

Which of the following molecules can act as a nucleophile?

<p>Water (D)</p> Signup and view all the answers

What is the main consequence of dehydration?

<p>A decrease in the total volume of bodily fluids. (B)</p> Signup and view all the answers

What type of bond is formed by the sharing of electron pairs between atoms?

<p>Covalent bond (D)</p> Signup and view all the answers

In what two ways can water act in chemical reactions?

<p>As both an acid and a base (B)</p> Signup and view all the answers

What is the primary characteristic of a substance with a high dielectric constant?

<p>It can easily break ionic bonds. (B)</p> Signup and view all the answers

Which of the following statements about dehydration is correct?

<p>It occurs when fluid loss is greater than intake. (A)</p> Signup and view all the answers

How does water's ability to act as both an acid and a base influence its role in reactions?

<p>It allows for greater versatility in chemical reactions. (C)</p> Signup and view all the answers

What is the dissociation constant of water (Kw) at 25 degrees Centigrade?

<p>$1.0 \times 10^{-14} \text{ (mol / L)}^2$ (B)</p> Signup and view all the answers

What is the relationship between pH and pOH in a neutral solution?

<p>pH + pOH = 14 (B)</p> Signup and view all the answers

Which of the following correctly expresses the formula for the dissociation constant (K)?

<p>$K = \frac{[H^+][OH^-]}{[H2O]}$ (D)</p> Signup and view all the answers

How does the concentration of H3O+ and OH- in pure water at 25 degrees Centigrade compare?

<p>Both are equal to $1 \times 10^{-7} \text{ mol / L}$ (D)</p> Signup and view all the answers

What does the term -log[H3O+] represent?

<p>pH (C)</p> Signup and view all the answers

Flashcards

Eukaryotic Cells

Cells with a membrane-bound nucleus containing DNA.

Prokaryotic Cells

Cells lacking a membrane-bound nucleus and a nuclear membrane.

Plasma Membrane

The outer boundary of a cell, controlling what enters and exits.

Nucleus

The cell's control center, containing DNA and the nucleolus.

Signup and view all the flashcards

Rough Endoplasmic Reticulum

ER with ribosomes, involved in protein synthesis.

Signup and view all the flashcards

Smooth Endoplasmic Reticulum

ER without ribosomes; involved in lipid and steroid synthesis.

Signup and view all the flashcards

Nucleolus

Region within the nucleus where ribosomes are assembled.

Signup and view all the flashcards

Golgi Apparatus

A cell organelle that modifies, sorts, and packages proteins.

Signup and view all the flashcards

Endoplasmic Reticulum (ER)

A network of flattened sacs and vesicles within the cell, continuous with the nuclear envelope. Proteins are transported and temporarily stored within the ER.

Signup and view all the flashcards

Mitochondria

Organelles responsible for cellular respiration and ATP production.

Signup and view all the flashcards

Lysosomes

Membrane-bound vesicles containing digestive enzymes that break down cellular waste and materials.

Signup and view all the flashcards

Cytosol

The fluid portion of the cytoplasm, excluding the organelles.

Signup and view all the flashcards

Cellular Respiration

The process by which cells break down nutrients to release energy in the form of ATP.

Signup and view all the flashcards

ATP

Adenosine triphosphate; the main energy currency of the cell.

Signup and view all the flashcards

Glycolysis

A metabolic pathway in the cytosol that breaks down glucose into pyruvate.

Signup and view all the flashcards

Microfilaments

Thin protein filaments composed of actin, involved in cell movement and support.

Signup and view all the flashcards

Homogenization

A technique used to disrupt cells and isolate their organelles.

Signup and view all the flashcards

Centrifugation

A method to separate cell components by spinning a sample at high speeds.

Signup and view all the flashcards

Homogenate

A suspension obtained from homogenization, containing intact cell organelles.

Signup and view all the flashcards

Salt Fractionation

A method to isolate biomolecules based on their salt solubility.

Signup and view all the flashcards

Chromatography

Separates components based on their different interactions with a medium.

Signup and view all the flashcards

Electrophoresis

Separates biomolecules based on size and charge using an electric field.

Signup and view all the flashcards

Ultracentrifugation

Centrifugation at extremely high speeds to separate very small particles.

Signup and view all the flashcards

Body water percentage

Adults have roughly 50-60% body water, children around 75%, and obese individuals have less than those who are not obese.

Signup and view all the flashcards

Water's role in dissolving

Water's polarity and ability to form hydrogen bonds allow it to dissolve many organic and inorganic molecules.

Signup and view all the flashcards

Intracellular vs. Extracellular water

About 60% of total body water is inside cells (intracellular), while 40% is outside cells (extracellular).

Signup and view all the flashcards

Water as nucleophile

Water can participate in chemical reactions because it's a nucleophile.

Signup and view all the flashcards

Water's role in maintaining pH

Water's slight dissociation ability makes it act as both an acid and a base, contributing to pH balance.

Signup and view all the flashcards

Dielectric constant

A measure of a material's resistance to forming electric fields. Water has a high dielectric constant.

Signup and view all the flashcards

Biochemical process analysis

Scientists use isotopes to study biochemical processes and metabolic pathways.

Signup and view all the flashcards

Levels of biological study

Biological studies can be done at different levels: whole animal, organ, tissue, cell, or organelle.

Signup and view all the flashcards

Water's dielectric constant

Water's ability to reduce the attraction between charged particles.

Signup and view all the flashcards

Dehydration

Loss of water when intake is less than volume loss.

Signup and view all the flashcards

Nucleophile

A molecule or ion that donates electrons to form a bond.

Signup and view all the flashcards

Covalent Bond

A chemical bond formed by sharing electron pairs between atoms.

Signup and view all the flashcards

Primary Bond

Strong chemical bonds.

Signup and view all the flashcards

Extracellular water

Fluid in plasma and interstitial spaces.

Signup and view all the flashcards

Dipole

Molecule with a partial positive and partial negative end.

Signup and view all the flashcards

Water as an acid/base

Water can donate or accept protons (hydrogen atoms).

Signup and view all the flashcards

Dissociation Constant of Water

The product of hydrogen ion (H+) and hydroxide ion (OH-) concentrations in water at equilibrium. It's equal to 10^-14 at 25°C.

Signup and view all the flashcards

pH + pOH = 14

The sum of pH and pOH is always 14 in an aqueous solution, representing the relationship between the acidity and alkalinity of a solution.

Signup and view all the flashcards

Logarithmic Relationship

The dissociation constant of water (Kw) can be expressed logarithmically, with -log[H+]=pH and -log[OH-]=pOH, leading to the equation pH + pOH = 14.

Signup and view all the flashcards

Kw Value

The value of Kw is 10^-14 (mol/L)^2 at 25°C, representing the equilibrium constant for the ionization of water. This value is always constant for aqueous solutions, regardless of the presence of acids or bases.

Signup and view all the flashcards

Study Notes

  • Proteins are high molecular weight polypeptides.
  • Protein classification can be based on components (simple or complex), overall shape (globular or fibrous), or function (catalytic, contraction, hormonal, etc).
  • Globular proteins have an axial ratio of less than 10, while fibrous proteins have an axial ratio greater than 10.
  • Protein structure is hierarchical, with primary, secondary, tertiary, and quaternary structures.
  • Primary structure is the linear sequence of amino acids.
  • Secondary structure includes a-helices and b-pleated sheets, stabilized by hydrogen bonds.
  • Tertiary structure is the three-dimensional arrangement of the polypeptide chain.
  • Quaternary structure involves the aggregation of multiple polypeptide chains.
  • Protein folding is driven by hydrophobic interactions, hydrogen bonds, disulfide bonds, and salt bridges.
  • Denaturation disrupts the native conformation of proteins, causing loss of biological activity.
  • Protein folding can be aided by accessory proteins such as chaperonins.
  • Proline and Glycine are frequently found in turns and bends of proteins.
  • There are 20 common amino acids.
  • Amino acids are classified by their R-groups as nonpolar, polar uncharged, polar charged, and aromatic.
  • Specific groups such as hydroxyl (-OH), sulfhydryl (-SH), and carboxyl (-COOH) play roles in protein synthesis, structure, and function.
  • pH affects the charge of amino acids.
  • Isoelectric point (pI) is the pH at which a protein has no net charge.
  • Peptide bonds connect amino acids in proteins
  • Disulfide bond forms between pairs of cysteine residues.
  • Protein structure is essential for its function.
  • Different types of bonds maintain the structure (e.g., hydrogen, hydrophobic, ionic, Van der Waals).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Prelim Biochemistry PDF

Description

This quiz explores the fascinating world of proteins, focusing on their classification, structure, and folding mechanisms. You'll learn about the different types of proteins, from globular to fibrous, and understand the hierarchical nature of protein structures. Test your knowledge on protein functionalities and the effects of denaturation.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser