Physiology and Pathophysiology Overview

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Questions and Answers

What is the primary role of mitochondria within a cell?

Produce adenosine triphosphate (ATP) (correct)

Store genetic material

Synthesize proteins

Facilitate cytoplasmic digestion

Which process results in the formation of two identical daughter cells?

Mitosis (correct)

Meiosis

Interphase

Cytokinesis alone

What component of the cell is primarily responsible for storing DNA?

Ribosomes

Cytoplasm

Nucleus (correct)

Endoplasmic reticulum

During which phase of the cell cycle does DNA replication occur?

Interphase Signup and view all the answers

Which of the following is NOT a function of lysosomes?

Synthesis of proteins Signup and view all the answers

What is produced during meiosis that differs from mitosis?

Egg and sperm cells Signup and view all the answers

What is the term for the process that reduces chromosome numbers for the formation of gametes?

Meiosis Signup and view all the answers

What occurs during prophase in cell division?

Chromosomes start to condense Signup and view all the answers

What does the term 'centromere' refer to in a chromosome?

Connection point of sister chromatids Signup and view all the answers

What happens to sister chromatids during anaphase?

They are pulled to opposite poles of the cell Signup and view all the answers

Which statement accurately describes the metaphase stage of mitosis?

Chromosomes line up along the metaphase plate Signup and view all the answers

Which of the following describes the role of the cell membrane?

It regulates the concentration of substances inside the cell Signup and view all the answers

Which type of molecules can pass through the lipid bilayer without assistance?

Small, non-polar materials Signup and view all the answers

What is meant by the term 'selectively permeable' in reference to the cell membrane?

It allows only certain substances to cross the membrane Signup and view all the answers

Which of the following substances would most likely require facilitated diffusion to enter a cell?

Glucose Signup and view all the answers

What is the primary requirement for active transport to occur across a cell membrane?

Energy from ATP Signup and view all the answers

What is the main characteristic of passive transport across the cell membrane?

It occurs without the expenditure of energy Signup and view all the answers

Which statement best describes the sodium-potassium pump?

It helps maintain an electrical gradient across the cell membrane. Signup and view all the answers

Which of these substances needs assistance to cross the cell membrane?

Glucose Signup and view all the answers

Which process is used to move very large molecules across the cell membrane?

Vesicle transport Signup and view all the answers

What is a characteristic of facilitated diffusion?

It uses transport proteins to help substances cross the membrane. Signup and view all the answers

During endocytosis, what happens to the molecules that are engulfed?

They are enclosed within a vesicle inside the cell. Signup and view all the answers

What is the main function of carrier proteins in facilitated diffusion?

To assist in the movement of polar molecules into the cell Signup and view all the answers

Which of the following statements about facilitated diffusion is false?

It can occur against a concentration gradient. Signup and view all the answers

What is the primary source of energy used in active transport?

Adenosine triphosphate (ATP) Signup and view all the answers

Which type of passive transport specifically refers to the movement of water?

Osmosis Signup and view all the answers

What happens to a cell placed in a hypertonic solution?

The cell shrivels as water diffuses out. Signup and view all the answers

Which of the following describes isotonic solutions?

Have no net movement of water across the cell membrane. Signup and view all the answers

Which type of molecules typically move through cell membranes by simple diffusion?

Very small, hydrophobic molecules Signup and view all the answers

What effect does a hypotonic solution have on a cell?

The cell swells and may burst. Signup and view all the answers

Osmotic pressure is determined primarily by what?

The concentration of solute Signup and view all the answers

Which of the following best describes facilitated diffusion?

Transport of substances aided by carrier proteins down their concentration gradient. Signup and view all the answers

What is the primary function of endocytosis in a cell?

Moving large particles and molecules into the cell Signup and view all the answers

Which of the following best describes phagocytosis?

The engulfing of large particles such as cells Signup and view all the answers

Receptor-mediated endocytosis is characterized by what key feature?

Selectivity due to binding of specific ligands to receptors Signup and view all the answers

What process is described as 'cellular drinking'?

Pinocytosis Signup and view all the answers

Which statement correctly describes exocytosis?

It expels materials into extracellular fluid. Signup and view all the answers

What role do feedback mechanisms play in homeostasis?

They help regulate the body's response to internal changes. Signup and view all the answers

What key factor differentiates passive transport from active transport?

The direction of the concentration gradient Signup and view all the answers

Which component is NOT part of the feedback mechanisms that help maintain homeostasis?

Osmotic pressure regulator Signup and view all the answers

Study Notes

Physiology & Pathophysiology

Physiology is the study of how things work normally within the body while pathophysiology focuses on how things work during disease.
Cells are the most basic building blocks of the body, and they organize to form tissues, organs, and organ systems.

Cell Components

The cytoplasm is an aqueous mass within the cell membrane that contains organelles, including:
- The nucleus: holds DNA, responsible for cellular division and reproduction.
- Mitochondria: fuel cellular activity by producing ATP.
- Ribosomes and the endoplasmic reticulum: synthesize proteins.
- Lysosomes: contain enzymes for cytoplasmic digestion.

Cell Division and Reproduction

Mitosis produces two identical daughter cells for body cell growth and repair.
Meiosis is a two-step process that creates sperm and egg cells, reducing the chromosome number from 46 to 23.
During interphase, the cell duplicates its contents and copies its DNA, creating two sister chromatids connected by a centromere.
The four phases of mitosis are:
- Prophase: Chromosomes condense, the nuclear envelope breaks down, and mitotic spindles form.
- Metaphase: Chromosomes line up along the metaphase plate.
- Anaphase: Sister chromatids are pulled apart.
- Telophase: The nuclear envelope reforms, chromosomes unfold, and cytokinesis (cytoplasm division) occurs.

Transport Across the Cell Membrane

The selectively permeable cell membrane regulates the concentration of substances within the cell, including ions, nutrients, and waste products.
The cell membrane acts as a gate, allowing only specific substances to enter or leave the cell.
Two categories of transport exist:
- Passive transport: requires no cellular energy.
- Active transport: requires energy from ATP.

Types of Passive Transport

Simple Diffusion: The movement of substances from an area of higher concentration to an area of lower concentration (down the concentration gradient). Example: oxygen moving into cells and carbon dioxide moving out.
Osmosis: The diffusion of water across a semipermeable membrane down its concentration gradient, driven by osmotic pressure created by solutes.
- Hypertonic solution: Higher solute concentration, water moves out of the cell, causing it to shrivel.
- Hypotonic solution: Lower solute concentration, water moves into the cell, causing it to swell and potentially burst.
- Isotonic solution: Same solute concentration, water moves in and out at the same rate.
Facilitated diffusion: Uses transport proteins and channel proteins for polar molecules like glucose to move across the cell membrane, which they cannot pass through via simple diffusion.

Types of Active Transport

Active transport: Requires energy (ATP) to move substances across the cell membrane, often against their concentration gradient, with the help of protein carriers and pumps.
Sodium-potassium pump (Na+/K+/ATPase): Moves sodium out of the cell and potassium into the cell, maintaining an electrical gradient.
Vesicle transport: For large molecules like proteins, uses vesicles for movement into and out of the cell (endocytosis and exocytosis).

Types of Endocytosis

Endocytosis: Cell membrane invaginates to form a pocket (vesicle) around a particle, taking it into the cell.
- Phagocytosis: Cellular eating, engulfing large particles like bacteria.
- Pinocytosis: Cellular drinking, taking in fluid.
- Receptor-mediated endocytosis: Selective process where external receptors bind a ligand and the cell responds by endocytosing it.

Exocytosis

Exocytosis: Expels material from the cell into the extracellular fluid. A vesicle containing the material fuses with the cell membrane, releasing the contents outside the cell.

Homeostasis

The body strives to maintain a state of internal balance called homeostasis.
External stressors like lack of nutrients or invasion by parasites can disrupt homeostasis and lead to disease.
Homeostasis is maintained through feedback mechanisms with three components:
- Sensor (receptor): Detects disruptions in homeostasis. - Control center: Regulates the body's response to disruptions. - Effector: Acts to restore homeostasis.

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Description

This quiz explores the fundamental concepts of physiology and pathophysiology, focusing on cell structure and function. It covers key components such as the nucleus, mitochondria, and the processes of mitosis and meiosis. Test your understanding of how these mechanisms contribute to health and disease.