Biology Exam Review: Intro to Biochemistry and Systems

A comprehensive set of practice questions covering biochemistry, cell biology, metabolism, genetics, and human physiology based on lecture notes.

What is a covalent bond?

When atoms share a pair of electrons, which can be polar or nonpolar, and is common in biological molecules such as $CO_2$.

In an ionic bond, at what value of $\Delta E$ do ions typically dissociate in water?

$$\Delta E > 1.7$$

Which linkage is found in lipids and connects the carboxyl group to the hydroxyl of glycerol to form triglycerides?

Ester Linkage

What are the primary structural components of Nucleic Acids?

They are made of $P,O,H,C,N$ and consist of a sugar, a phosphate group, and a nitrogenous base.

Which organelle in eukaryotic cells is responsible for inactivating toxins?

Peroxisomes

What is the difference between Rough ER and Smooth ER?

Rough ER has ribosomes attached and is where some $RNA$ is translated into polypeptide chains; Smooth ER lacks ribosomes and is involved in packaging proteins into vesicles and synthesizing lipids.

What is the role of Chromatin in the nucleus?

It is the total collection of all $DNA$ molecules and associated proteins.

How do channel proteins and carrier proteins differ in facilitated diffusion?

Channel proteins form hydrophilic channels (tunnels) through the membrane, whereas carrier proteins undergo a conformational change in shape to move solutes.

Define the 2nd Law of Thermodynamics.

Events in the universe have direction and proceed from a state of higher energy to a state of lower energy.

What is competitive inhibition?

When a molecule competes with the substrate for the active site of an enzyme.

What is the full chemical equation for cellular respiration?

$$C_6H_{12}O_6 + 6O_2 + 36ADP + 36P_i \rightarrow 6CO_2 + 6H_2O + 36ATP + \text{Waste heat}$$

What are the four stages of cellular respiration?

1. Glycolysis, 2. Pyruvate Oxidation, 3. Krebs Cycle, 4. Electron Transport Chain.

In the Electron Transport Chain, which component passes electrons to oxygen to make water?

Cytochrome oxidase (IV)

How many $ATP$ molecules are produced for every hydrogen ion ($H^+$) pumped out of the matrix?

$$1\,ATP$$

What are the products of the light reactions in photosynthesis?

Oxygen, $ATP$, and $NADPH$

Where do the dark reactions (Calvin Cycle) take place within the chloroplast?

In the Stroma

Which enzyme is responsible for breaking hydrogen bonds to separate DNA strands during replication?

Helicase

What is the difference between the leading strand and the lagging strand in DNA replication?

The leading strand is replicated continuously, while the lagging strand is built away from the replication fork in Okazaki fragments.

What is a nonsense mutation?

A change in the $DNA$ sequence that results in a premature stop codon.

What is the role of the lac operon being inducible?

It is normally off, but the presence of lactose (allolactose) inactivates the repressor and turns the operon on.

In the urinary system, what is the function of the Glomerulus?

It is the site where filtration occurs as blood under high pressure moves through its walls into the Bowman's capsule.

Which hormone, produced by the Beta cells of the Islets of Langerhans, decreases blood glucose?

Insulin

What is the function of aldosterone?

Produced in the Adrenal Cortex, it promotes the reabsorption of $Na^+$ ions, causing water to follow, which increases blood volume and blood pressure.

What occurs during the depolarization phase of an action potential?

Sodium ions ($Na^+$) rush into the neuron, causing the inside of the cell to become more positive.

What is the importance of phagocytosis in the immune response?

It involves the ingestion and breakdown of pathogens by phagocytes, destroying invaders quickly and helping activate advanced defenses.

What is the Allee Effect in population dynamics?

It occurs when a population cannot survive or fails to reproduce enough to offset mortality because the population density is too low.

Define Commensalism in a community interaction.

A relationship where one organism benefits and the other is unaffected.