Biochemistry Final FRQs

What are the two main components of a fat molecule?

The two main components of a fat molecule are a glycerol backbone and three fatty acid tails.

Describe the process of dehydration synthesis in the formation of a fat molecule.

In dehydration synthesis, the hydroxyl group on the glycerol backbone reacts with carboxyl groups of fatty acids to create a fat molecule with 3 fatty acid tails.

How do saturated and unsaturated fatty acids differ in terms of their chemical structure?

Saturated fatty acids have as many hydrogen atoms as possible attached to the carbon skeleton, while unsaturated fatty acids have fewer hydrogens attached.

What is the significance of cis and trans configurations in unsaturated fatty acids?

Cis configurations have hydrogens on the same side, creating a bend, while trans configurations have them on opposite sides, affecting fat behavior.

What is the role of triglycerides in the human body?

Triglycerides are vital for energy storage and make up adipose tissue, which can grow when excess lipids are stored.

Why are omega-3 and omega-6 fatty acids considered essential?

They must be obtained from the diet as the body cannot produce them, and they are precursors for many biological molecules.

Describe the structure of phospholipids in cell membranes.

Phospholipids consist of a glycerol backbone, two fatty acid tails, and a phosphate group that may have modifiers like choline.

How do micelles form?

Micelles form when phospholipids are placed in water, with hydrophilic heads facing outward and hydrophobic tails inward.

What distinguishes steroids from other lipids?

Steroids are identified by their structure of four fused carbon rings, unlike other lipids which have long hydrocarbon chains.

What is the impact of trans fats on human health?

Trans fats make fats more solid at room temperature and increase the risk of heart disease and stroke.

What is the primary role of membrane proteins in biological membranes?

Membrane proteins give each type of membrane its functional properties and facilitate cellular processes like signaling.

What is the difference in protein composition between the myelin membrane and membranes involved in ATP production?

Myelin membranes have 25% membrane mass as protein, while ATP production membranes have 75% protein mass.

How do transmembrane proteins interact with the lipid bilayer?

Transmembrane proteins function on both sides of the bilayer and transport molecules directly across the membrane.

What are the 3 types of transports in cells?

Passive transport does not require energy, facilitated transport helps larger molecules cross, and active transport requires energy to move substances against their gradient.

Define anabolic pathways.

Anabolic pathways build up smaller molecules into larger ones, requiring energy input for reactions.

Define catabolic pathways.

Catabolic pathways break down complex molecules into simpler ones, releasing energy during the process.

Define metabolism.

Metabolism is the total of chemical reactions in a cell that create and utilize energy for growth and maintaining functions.

What is cellular respiration?

Cellular respiration is the process in which cells obtain energy by breaking down glucose and capturing energy as ATP.

What is photosynthesis?

Photosynthesis is the process by which plants convert CO2 and sunlight into glucose.

Explain the difference between substrate-level and oxidative phosphorylation.

Substrate-level phosphorylation produces ATP directly in glycolysis and Krebs cycle, while oxidative phosphorylation uses the electron transport chain to produce ATP.

What is gluconeogenesis?

Gluconeogenesis maintains blood glucose levels during fasting by synthesizing glucose from non-carbohydrate sources.

What is the purpose of the citric acid cycle?

The citric acid cycle is crucial for energy production and provides precursors for biosynthetic reactions.

What is the electron transport chain?

The electron transport chain is a series of complexes in the mitochondria that create ATP through a proton gradient.

What distinguishes exogenous from endogenous lipid pathways?

Exogenous pathways transport dietary lipids, while endogenous pathways transport lipids synthesized by the body.

What effect does a ketogenic diet have on the brain?

A ketogenic diet provides ketone bodies as alternative energy sources for the brain, potentially improving brain function in neurodegenerative diseases.