Bio Unit 3

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of water in biological processes?

It serves as a structural component of cells.

It is the solvent in which most life processes occur. (correct)

It serves as a solid medium for organisms.

It is a major energy source for chemical reactions.

How does cohesion in water affect plant transpiration?

It helps water to be pulled up through the xylem. (correct)

It allows nutrients to dissolve in water.

It causes water to evaporate from the soil.

It reduces water retention in leaves.

Which property of water allows it to act as a good solvent for hydrophilic substances?

High viscosity

High density

Polar covalent bonds (correct)

Hydrophobic interactions

What term describes water's ability to stick to a solid surface, aiding in the movement of water through plants?

Adhesion Signup and view all the answers

What role does buoyancy play in aquatic organisms?

It helps them to float and maintain their position in water. Signup and view all the answers

How does viscosity affect the movement of fish in water?

It increases the resistance fish face while swimming. Signup and view all the answers

What is a swim bladder's function in certain fish?

To regulate buoyancy and floatation. Signup and view all the answers

What happens to the viscosity of water as more substances dissolve in it?

Viscosity increases. Signup and view all the answers

What determines the permeability of a molecule across the cell membrane?

Charge and size Signup and view all the answers

What is the primary role of channel proteins in cell membranes?

To facilitate passive movement of specific molecules Signup and view all the answers

What is denaturation in the context of proteins?

The irreversible change in the functional shape of a protein Signup and view all the answers

During osmosis, where does water move relative to solute concentration?

Towards areas of higher solute concentration Signup and view all the answers

What characterizes integral proteins in the membrane?

They can interact with both polar and non-polar parts of the bilayer Signup and view all the answers

What distinguishes facilitated diffusion from regular diffusion?

Facilitated diffusion involves channel proteins Signup and view all the answers

Which statement about active transport is true?

It requires energy to move molecules against their concentration gradient Signup and view all the answers

What is one role of glycoproteins in the cell membrane?

Cell recognition and joining cells together Signup and view all the answers

How does the fluid mosaic model describe the cell membrane?

As a dynamic mix of lipid layers and mobile proteins Signup and view all the answers

What is the primary property of water that makes it a good thermal conductor?

It can easily release heat from metabolic processes. Signup and view all the answers

What type of bond is formed during the condensation reaction between monosaccharides?

Glycosidic bond Signup and view all the answers

Which polysaccharide serves as a structural component in plant cell walls?

Cellulose Signup and view all the answers

What is the main function of glycoproteins in the cell?

Cell recognition Signup and view all the answers

What characteristic of saturated fatty acids prevents them from being liquid at room temperature?

Presence of single bonds Signup and view all the answers

What is the difference between trans-unsaturated fatty acids and cis-unsaturated fatty acids?

Trans has hydrogen atoms on opposite sides, while cis has them on the same side. Signup and view all the answers

What is the primary function of triglycerides in adipose tissue?

Storing energy long-term Signup and view all the answers

Which of the following accurately describes the structure of a phospholipid?

Two fatty acids, a glycerol backbone, and a phosphate group Signup and view all the answers

What is the role of hydrolysis in biological systems?

To split larger molecules into smaller ones Signup and view all the answers

What does the term 'amphipathic' refer to in the context of phospholipids?

Containing both hydrophobic and hydrophilic regions Signup and view all the answers

Why do animals require dietary sources of certain amino acids?

They lack the ability to synthesize 11 out of 20 amino acids. Signup and view all the answers

Which carbohydrate serves as the primary energy storage molecule in plants?

Starch Signup and view all the answers

What is the significance of specific heat capacity in maintaining aquatic environments?

It regulates temperature stability in water bodies. Signup and view all the answers

Which component of the lipid bilayer is primarily responsible for cellular permeability?

Phospholipid tails Signup and view all the answers

What type of molecules can easily pass through the phospholipid bilayer?

Non-polar steroid molecules Signup and view all the answers

Study Notes

Water's Properties and Roles in Life

Water is the medium for most life processes, enabling chemical reactions between dissolved molecules.
Water's polar covalent bonds create partial charges, leading to hydrogen bonding. These bonds give water unique properties like cohesion and adhesion.
Cohesion: Water molecules stick together, crucial for transpiration (water movement in plants). Evaporation from leaves creates tension pulling water up the xylem, forming a continuous column. Cohesion creates surface tension, vital for aquatic habitats.
Adhesion: Water sticks to solid surfaces like xylem walls, enabling capillary action—water's upward movement against gravity. Capillary action transports water from soil through plants.
Water is a good solvent due to its polarity, dissolving hydrophilic (polar) solutes and ions, but not hydrophobic (non-polar) substances. Metabolism relies on aqueous solutions. Water acts as an excellent transport medium in plants (xylem for water and minerals, phloem for sugars) and animals (blood plasma).
Buoyancy: Water exerts an upward force against gravity (floating). Aquatic organisms often have equal density to water.
Viscosity: Water's resistance to flow. Motion through water requires overcoming this property.
Thermal Conductivity: Water readily transmits heat, helpful for dissipating heat from metabolic processes.
Specific Heat Capacity: Water needs a significant energy change to alter its temperature, acting as a buffer against large temperature fluctuations. This property is vital for aquatic organisms and maintains relatively stable body temperatures in animals through blood plasma and cell water.

Carbohydrates: Structure and Function

Carbohydrates are carbon-based molecules forming branched or unbranched chains or rings.
Macromolecules are built from small monomers (monosaccharides) through condensation reactions, removing water to create bonds.
Glycosidic bonds: Bonds formed between monosaccharides during condensation reactions, creating disaccharides and polysaccharides. 1-4 and 1-6 linkages distinguish different polysaccharide structures like amylose and amylopectin (starch) and glycogen.
Hydrolysis: Adding water to break glycosidic bonds; essential for digestion.
Monosaccharides: Simple sugars (e.g., glucose). Trioses, pentoses, and hexoses are classified by carbon number.
Polysaccharides: Complex carbohydrates; important for structural support and energy storage.
Cellulose: a structural polysaccharide in plant cell walls. Beta-glucose forms linear chains. Hydrogen bonds between chains provide strength.
Starch: energy storage in plants; composed of amylose (linear) and amylopectin (branched).
Glycogen: energy storage in animals; highly branched, more readily broken down.
Glycoproteins and glycolipids: Proteins and lipids with attached carbohydrate chains. These structures play key roles in cell recognition.
Blood type antigens are glycoproteins, unique carbohydrate patterns enabling cell recognition and response.

Lipids: Diverse Structures

Lipids are hydrophobic (non-polar) molecules dissolving in non-polar solvents.
Fatty acids: Long hydrocarbon chains with a carboxyl group.
Triglycerides: Glycerol + 3 fatty acids, crucial for long-term energy storage and thermal insulation in adipose tissue.
Phospholipids: Glycerol + 2 fatty acids + phosphate group. The hydrophilic phosphate head and hydrophobic fatty acid tails arrange in a bilayer, forming cell membranes.
Saturated fatty acids: Straight chains, solid at room temperature.
Unsaturated fatty acids: Contain double bonds; Cis-unsaturated acids are bent, while trans-unsaturated acids are straight. The shape affects the melting point and, indirectly, the properties of materials like oils and fats.
Phospholipids form a bilayer in water where polar "heads" face outwards and nonpolar "tails" face inwards, creating a barrier.
Steroids have a unique four-ring structure; these non-polar molecules can easily pass through cell membranes.

Proteins: Diverse Functional Molecules

Proteins are long chains of amino acids connected by peptide bonds formed in condensation reactions.
Amino acids: 20 different types; Plants can manufacture all, while animals must obtain from diet.
Polypeptides: Chains of amino acids.
Proteins fold into specific 3D shapes crucial for their function.
Denaturation: Loss of protein structure due to heat or pH changes; this can significantly alter a protein's function.
Proteome: an organism's complete set of proteins.

Cell Membranes: Structure and Function

Cell membranes consist of a lipid bilayer (phospholipids) and proteins (integral and peripheral).
Selectively permeable barrier: Cell membranes control what enters and leaves the cell, based on size and charge of molecules.
Diffusion: Passive movement of molecules from high to low concentration. Small, non-polar molecules diffuse directly through the membrane.
Osmosis: Passive movement of water across a membrane from low to high solute concentration.
Facilitated diffusion: Passive movement of molecules through channel proteins.
Active transport: Movement of molecules against their concentration gradient, requiring energy (ATP).
Fluid mosaic model: A dynamic representation of the membrane structure, with components moving around.
Glycoproteins and glycolipids on the cell surface play roles in cell recognition and interactions.

Studying That Suits You

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

Description

Water A1.1.1 Water needed for life A1.1.2 Bonding within Water A1.1.3 Cohesion A1.1.4 Adhesion A1.1.5 Solvent Properties of Water A1.1.6 Properties of Water Carbohydrates and Lipids B1.1.1 Carbon Atoms B1.1.2 Condensation Reactions B1.1.3 Hydrolysis B1.1.4 Monosaccharides B1.1.5 Polysaccharides B1.1.6 Cellulose B1.1.7 Glycoproteins B1.1.8 Hydrophobic Properties of Lipids B1.1.9 Triglycerides and Phospholipids B1.1.10 Types of Fatty Acids B1.1.11 Function of triglycerides B1.1.12 Amphipathic Molecules B1.1.13 Steroids

Proteins B1.2.1 Amino Acid Structure B1.2.2 Dipeptide Formation B1.2.3 Dietary Requirements for Amino Acids B1.2.4 Variety of Peptide Chains B1.2.5 pH and Temperature on Proteins

Cell Membranes B2.1.1 Lipid bilayers B2.1.2 Diffusion across membranes B2.1.3 Lipid Bilayers as barriers B2.1.4 Types of Membrane Proteins B2.1.5 Osmosis B2.1.6 Facilitated Diffusion & Channel Proteins B2.1.7 Protein Pumps B2.1.8 Membrane Permeability B2.1.9 Glycoproteins and glycolipids B2.1.10 Fluid Mosaic Model