Exam 1 Packet

What is the proper physiological term for all the water contained within the human body?

Total body water

Fluid located inside of cells is known as _____.

Intracellular fluid (ICF)

What is the general term for all fluid located outside of cells?

Extracellular fluid (ECF)

Extracellular fluid that is specifically found within the blood is called _____.

Plasma

Fluid located outside of cells and outside of the blood is known as _____.

Interstitial fluid (ISF)

What is the relative percentage of Intracellular Fluid (ICF) compared to Extracellular Fluid (ECF) in the body?

ICF is 67% (2/3) and ECF is 33% (1/3).

What two sub-compartments make up the Extracellular Fluid (ECF)?

Plasma and Interstitial fluid (ISF)

Within the ECF, what is the relative percentage of Interstitial Fluid compared to Plasma?

Interstitial Fluid is 80% and Plasma is 20%.

The smallest units capable of performing all basic life functions are called _____.

Cells

Name the four major groups into which cells and tissues are classified.

• Neurons

• Muscle cells

• Epithelial cells

• Connective tissue cells.

Which specific cell type is specialized for transmitting electrical signals for communication?

Neurons

What is the defining characteristic of muscle cells?

They are specialized to contract on a voluntary or involuntary basis.

Term/Definition: Epithelial cells

Sheet-like cells with little extracellular matrix that line body surfaces and hollow organ lumens to function as barriers.

Which tissue type is characterized by having a large amount of extracellular matrix used to anchor and link body structures?

Connective tissue

Define Homeostasis.

The maintenance of a relatively constant internal environment.

A _____ is the physiological value around which a normal range fluctuates in homeostasis.

Set point

How does negative feedback maintain homeostasis?

It reverses a change in a physiological condition to return it to the set point.

What is the primary difference between negative feedback and positive feedback?

Negative feedback reverses a change, while positive feedback intensifies a change.

Which organelle consists of a lipid bilayer with cholesterol and maintains the boundary of the cell?

Plasma membrane

What is the primary function of the cell nucleus?

To house DNA which dictates cellular function and protein synthesis.

The dark oval structure inside the nucleus responsible for synthesis of ribosomal RNA is the _____.

Nucleolus

What is the function of the cytosol?

It serves as the site for cell metabolism and energy storage in the form of triglycerides or glycogen.

Which organelle is a series of flattened sacs dotted with ribosomes and involved in protein synthesis?

Rough ER

Identify the functions of the Smooth Endoplasmic Reticulum (SER).

Lipid synthesis, post-translational protein processing, molecule transport, and calcium storage.

Which organelle acts as a packaging and sorting center for proteins near the endoplasmic reticulum?

Golgi apparatus

What is the primary function of the mitochondria?

ATP synthesis

_____ are granular, saclike organelles that contain digestive enzymes to break down debris.

Lysosomes

What is the specific function of peroxisomes?

The breakdown of toxic substances, including hydrogen peroxide.

Identify the barrel-shaped organelles possibly involved in molecule transport between the nucleus and cytoplasm.

Vaults

Which structures are granular organelles composed of proteins and rRNA that translate mRNA?

Ribosomes

The _____ consist of two cylindrical bundles of protein filaments that direct mitotic spindle development.

Centrioles

What are the three components of the cytoskeleton?

• Microfilaments

• Intermediate filaments

• Microtubules.

What molecule in the plasma membrane increases fluidity and reduces permeability to water?

Cholesterol

The term _____ describes molecules that have both hydrophobic (nonpolar) and hydrophilic (polar) parts.

Amphipathic

What is the glycocalyx and what is its purpose?

A layer of membrane carbohydrates that functions in cell recognition and protection

Give an example of a type of microfilament found in the cytoskeleton.

Actin

A _____ is the functional length of DNA that provides instructions to build a specific protein.

Gene

What is a chain of amino acids linked by peptide bonds called?

Polypeptide

Is protein synthesis classified as an anabolic or catabolic reaction?

Anabolic

What is the definition of a 'triplet' in the context of DNA?

A sequence of three nucleotides in DNA that codes for a specific amino acid.

A sequence of three nucleotides in mRNA that codes for an amino acid is called a(n) _____.

Codon

Which enzyme binds to the promoter sequence of DNA to begin transcription?

RNA polymerase

Where does the process of translation take place within the cell?

In the cytoplasm (on ribosomes)

What is the role of Transfer RNA (tRNA) in protein synthesis?

It carries the appropriate amino acid to the ribosome by interacting with the mRNA codon.

In a ribosome, which site (A or P) holds the tRNA with the last amino acid added to the chain?

P site

In a ribosome, which site (A or P) holds the tRNA with the next amino acid to be added?

A site

What is an anticodon?

A sequence of three nucleotides on tRNA that is complementary to an mRNA codon.

Which chemical tag targets a protein for degradation by a proteasome?

Ubiquitin

Distinguish between catabolic and anabolic reactions.

Catabolic reactions break down molecules to release energy; anabolic reactions use energy to build molecules.

Type of Metabolic Reaction: Hydrolysis

Definition: A reaction that uses water to break a chemical bond.

Type of Metabolic Reaction: Condensation

Definition: A reaction where two molecules join together, producing water as a byproduct.

What occurs during a phosphorylation reaction?

A phosphate group is added to a molecule.

What occurs during a dephosphorylation reaction?

A phosphate group is removed from a molecule.

In metabolic terms, what is oxidation?

The loss of electrons from a substance.

In metabolic terms, what is reduction?

The gain of electrons by a substance.

What are the characteristics of molecules that can cross the plasma membrane by simple diffusion?

They are typically small, nonpolar, and hydrophobic (e.g., O2​, CO2​, fatty acids).

Passive transport is the movement of a substance _____ its concentration gradient.

Down

Does passive transport require the expenditure of metabolic energy (ATP)?

No

Is the concentration of Potassium (K⁺) higher inside the cell or outside the cell?

Inside the cell

Is the concentration of Sodium (Na⁺) higher inside the cell or outside the cell?

Outside the cell

In a typical resting cell, is the Intracellular Fluid (ICF) more positive or more negative than the Extracellular Fluid (ECF)?

More negative

What are the three general factors that affect the rate of simple diffusion?

• Magnitude of the driving force

• Membrane surface area

• Membrane permeability

Identify four factors that influence the permeability of a membrane to a specific molecule.

• Lipid solubility

• Size/shape of the molecule

• Membrane thickness

• Temperature.

Which type of channel is always open and allows ions to move across the membrane constantly?

Leaky channels

_____ is a form of mediated transport that uses a transmembrane protein to move solutes down their gradient through conformational changes.

Facilitated diffusion

What are the three factors that affect the rate of transport through a carrier protein?

• Transport rate of individual carriers

• Number of carriers

• Magnitude of the gradient.

What is the primary difference between primary and secondary active transport?

Primary uses ATP directly; secondary uses an electrochemical gradient established by primary transport.

Distinguish between co-transport and counter-transport in active transport.

Co-transport moves substances in the same direction; counter-transport moves them in opposite directions.

Define Osmolarity.

The total solute concentration of a solution.

What is the difference between osmolarity and tonicity?

Osmolarity is a measure of total solutes; tonicity describes how a solution affects cell volume (shrink/swell).

_____ describes the shrinking of a red blood cell when placed in a hypertonic solution.

Crenation

What is osmotic pressure?

The pressure that must be applied to stop the osmotic movement of water.

Identify the three types of endocytosis.

• Phagocytosis

• Pinocytosis

• Receptor-mediated endocytosis

Which cellular transport mechanism involves adding material to the plasma membrane?

Exocytosis

Are most amine chemical messengers hydrophilic or hydrophobic?

Hydrophilic

Compare paracrine and autocrine messengers.

Paracrines act on neighboring cells; autocrines act on the same cell that released them.

How do hormones reach their target cells in the body?

They are released into the blood and transported throughout the body.

Which functional class of messengers is released by neurons into a synapse to signal a target cell?

Neurotransmitters

Are steroid messengers lipophilic or lipophobic?

Lipophilic

Which receptor type allows for the fastest cellular response to a ligand?

Channel-linked (fast ligand-gated) receptors.

What role does a G protein play in signal transduction?

It acts as a molecular switch to link a receptor to an effector protein (like an ion channel or enzyme).

In the cAMP second messenger system, which enzyme is activated by the G protein to produce cAMP?

Adenylate cyclase

What is the function of Protein Kinase A (PKA) in the cAMP system?

It phosphorylates target proteins to produce a cellular response.