Biology Macromolecules and Carbohydrates

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Questions and Answers

What process typically breaks down macromolecules into monomers?

Hydrolysis (correct)

Dehydration synthesis

Reduction

Oxidation

Which of the following is true regarding carbohydrates?

They are primarily made of nitrogen and oxygen.

They are divided into monosaccharides, disaccharides, and polysaccharides. (correct)

They have a general structural formula of C2H2O.

They include only simple sugars.

What distinguishes polysaccharides from monosaccharides and disaccharides?

They have a 2:1 ratio of hydrogen to oxygen.

They can contain hundreds of monosaccharides. (correct)

They are only made from glucose.

They are always soluble in water.

Which carbohydrate serves as the main energy-supplying compound of the body?

Glucose Signup and view all the answers

What role do triglycerides primarily serve in the body?

Cellular energy Signup and view all the answers

Which statement about lipids is correct?

They contain carbon, hydrogen, and oxygen. Signup and view all the answers

Which of the following carbohydrates cannot be digested by humans?

Cellulose Signup and view all the answers

How are disaccharides formed from monosaccharides?

By dehydration synthesis Signup and view all the answers

What are the two types of covalent bonds that fatty acids can have?

Single and double Signup and view all the answers

Which of the following statements accurately describes triglycerides?

They can be either solid or liquid at room temperature. Signup and view all the answers

What is the main structural difference between triglycerides and phospholipids?

Phospholipids have a phosphate group. Signup and view all the answers

What role do steroids play in the body?

They serve as an important component of cell membranes. Signup and view all the answers

Which function is NOT attributed to prostaglandins?

Participating in nutrient absorption Signup and view all the answers

Which fat-soluble vitamin is NOT classified among vitamins D, E, and K?

Vitamin A Signup and view all the answers

What type of lipid are leukotrienes primarily involved in?

Allergic and inflammatory responses Signup and view all the answers

What characteristic makes phospholipids unique among lipids?

They have both polar and nonpolar regions. Signup and view all the answers

What primarily drives the process of diffusion?

Kinetic energy of particles Signup and view all the answers

What component forms the basic framework of the plasma membrane?

Lipid bilayer Signup and view all the answers

Which factor does NOT influence the rate of diffusion across plasma membranes?

Color of the solute Signup and view all the answers

Which type of molecules can diffuse across the lipid bilayer without transport proteins?

Hydrophobic molecules Signup and view all the answers

Which type of membrane protein can be removed without affecting the membrane's integrity?

Peripheral proteins Signup and view all the answers

What is the role of integral membrane proteins in facilitated diffusion?

To assist specific substances across the membrane Signup and view all the answers

What is the primary function of the glycocalyx?

Help cells recognize and adhere to one another Signup and view all the answers

Which characteristic describes the lipid bilayer of the plasma membrane?

Amphipathic Signup and view all the answers

How does channel-mediated facilitated diffusion primarily function?

By allowing solutes to move down their concentration gradient through a channel Signup and view all the answers

What type of proteins extend into or across the lipid bilayer?

Transmembrane proteins Signup and view all the answers

Which of the following substances is most likely to use carrier-mediated facilitated diffusion?

Glucose Signup and view all the answers

What happens to a transporter in carrier-mediated facilitated diffusion after a solute binds?

It undergoes a conformational change Signup and view all the answers

How does the fluidity of the membrane compare to cooking oil?

Membranes are fluid structures similar to cooking oil Signup and view all the answers

Which type of protein functions as receptors and transporters in the plasma membrane?

Membrane proteins Signup and view all the answers

Which type of diffusion is used for substances that are too polar or charged to cross the lipid bilayer directly?

Facilitated diffusion Signup and view all the answers

Which lipid is weakly amphipathic within the plasma membrane?

Cholesterol Signup and view all the answers

What is the primary role of receptor-mediated endocytosis?

To selectively uptake large molecules and particles Signup and view all the answers

Which of the following is NOT a type of vesicular transport mentioned?

Diffusion Signup and view all the answers

Which type of cells are known as phagocytes?

Neutrophils and macrophages Signup and view all the answers

What initiates the process of phagocytosis in cells?

Pseudopod formation Signup and view all the answers

What is the function of microfilaments in the cytoskeleton?

To provide structural support and assist in movement Signup and view all the answers

How do secretory vesicles release their contents during exocytosis?

By fusing with the plasma membrane Signup and view all the answers

Which of the following correctly describes cytosol?

The aqueous environment for metabolic reactions Signup and view all the answers

Which process involves both endocytosis and exocytosis?

Transcytosis Signup and view all the answers

Study Notes

Macromolecules and Monomers

Macromolecules break down into monomers primarily through hydrolysis.
Molecules with the same molecular formula but different structures are termed isomers.

Carbohydrates

Carbohydrates are key energy sources, comprising sugars, starches, glycogen, and cellulose.
They have a general formula of CH2O, indicating one carbon atom for each water molecule.
Classified into three major groups: monosaccharides, disaccharides, and polysaccharides.

Simple Sugars

Monosaccharides: Simple sugars with 3-7 carbon atoms; glucose is a primary energy source known as a hexose.
Disaccharides: Formed from two monosaccharides via dehydration synthesis; can revert to simple sugars through hydrolysis (e.g., sucrose from glucose and fructose).

Polysaccharides

Comprise large chains of monosaccharides; may contain hundreds of units.
Glycogen is the primary polysaccharide in humans, stored in the liver and muscles.
Starches are plant-based polysaccharides formed from glucose; cellulose, also made from glucose, is indigestible by humans.

Lipids

Lipids contain carbon, hydrogen, and oxygen but lack the 2:1 hydrogen-oxygen ratio found in carbohydrates.
They are hydrophobic, mostly insoluble in water, achieving solubility via lipoprotein formation.

Fatty Acids

Serve as building blocks for triglycerides and phospholipids.
Fatty acids can be saturated (single bonds) or unsaturated (one or more double bonds).
Essential fatty acids must be obtained from diet; the body cannot synthesize them.

Triglycerides

Most abundant lipids, providing cellular energy, protection, and insulation.
Can be liquid (oils) or solid (fats) at room temperature; provide over double the energy per gram compared to carbohydrates or proteins.
Composed of glycerol and fatty acids; unlimited storage in adipose tissue.

Phospholipids

Contain two fatty acids and a phosphate group on a glycerol backbone, vital for membrane structure.
Amphipathic, possessing both polar and nonpolar regions.

Steroids

Characterized by four carbon rings; include essential hormones and cholesterol.
Cholesterol is critical for cell membrane integrity and as a precursor for steroid synthesis.

Other Lipids

Eicosanoids: Include prostaglandins and leukotrienes, involved in inflammation and hormone response.
Fat-soluble vitamins (A, D, E, K) are also considered lipids.

Plasma Membrane

A flexible barrier surrounding the cytoplasm, described by the fluid mosaic model composed of proteins and lipids.
The lipid bilayer consists of phospholipids, cholesterol, and glycolipids.

Membrane Protein Arrangement

Integral proteins penetrate the bilayer, while peripheral proteins are found on the membrane surface.
Integral proteins may function as channels or carriers, facilitating the transport of substances.

Functions of Membrane Proteins

Serve roles as ion channels, carriers, receptors, enzymes, linkers, and cell identity markers.

Membrane Fluidity

Membranes are fluidic, with lipids and proteins moving within the bilayer.
Diffusion rates are affected by concentration gradient, temperature, size of solute, surface area, and distance.

Transport Mechanisms

Simple Diffusion: Nonpolar molecules move directly across the lipid bilayer.
Facilitated Diffusion: Polar solutes utilize transport proteins to cross the membrane, either through channels or carriers.
Osmosis and Vesicular Transport: Include endocytosis (intake via vesicles) and exocytosis (release via fusion with plasma membrane).

Cytoplasm

Comprises cytosol, a fluid containing dissolved solutes and inclusions; medium for metabolic reactions.
The cytoskeleton supports cell shape and movement, consisting of microfilaments, intermediate filaments, and microtubules.

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Description

This quiz explores the structure and function of macromolecules, specifically focusing on carbohydrates. You'll learn about how carbohydrates break down into monomers through hydrolysis, and the concept of isomers. Understand the essential roles carbohydrates play in providing energy and building structural units in living organisms.