L1 - Cell and Transport mechanism

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary characteristic of the plasma membrane?

It is a rigid structure that maintains cell shape.

It is impermeable to all substances.

It is a semipermeable barrier that controls substance entry and exit. (correct)

It only allows water to pass freely in and out.

Which part of the phospholipid molecule is hydrophilic?

Head (correct)

Cholesterol portion

Hydrophobic end

Tail

How does homeostasis contribute to the functioning of the human body?

It organizes the body solely from cells to organs without interaction.

It eliminates the need for biological functions and processes.

It prevents any changes in the external environment.

It maintains a stable internal environment despite external changes. (correct)

Which structure is considered the functional unit of life?

Cell Signup and view all the answers

What process allows specific substances to pass through the plasma membrane without energy expenditure?

Facilitated diffusion Signup and view all the answers

What role does cholesterol play in the plasma membrane?

It helps to stabilize the structure and fluidity of the membrane. Signup and view all the answers

What defines the fluid mosaic model of the cell membrane?

Proteins and lipids are distributed unevenly within the membrane. Signup and view all the answers

Which mechanism would NOT contribute to maintaining homeostasis in the body?

Environmental changes Signup and view all the answers

What form does DNA take in non-dividing cells?

Chromatin Signup and view all the answers

Which organelle is known as the 'Powerhouse of the cell'?

Mitochondria Signup and view all the answers

What is the primary function of ribosomes?

Protein synthesis Signup and view all the answers

What distinguishes the rough endoplasmic reticulum from the smooth endoplasmic reticulum?

Presence of ribosomes Signup and view all the answers

Which organelle modifies, packages, and transports materials out of the cell?

Golgi Apparatus Signup and view all the answers

What type of enzymes do lysosomes contain?

Digestive enzymes Signup and view all the answers

What is the primary role of the cytoskeleton in a cell?

Giving shape and support to the cell Signup and view all the answers

Which component is not part of the endoplasmic reticulum?

Mitochondria Signup and view all the answers

Which of the following statements is true regarding mitochondria?

They contain their own DNA and produce ATP. Signup and view all the answers

The main function of the smooth endoplasmic reticulum is to?

Detoxify drugs and synthesize fats Signup and view all the answers

Which factor does NOT positively affect the rate of diffusion?

Thickness of the membrane Signup and view all the answers

What type of transport mechanism requires a transport protein but does not require energy?

Facilitated diffusion Signup and view all the answers

What is the primary function of the Na+/K+ pump?

Move sodium ions out and potassium ions into the cell Signup and view all the answers

Which type of carrier protein transports two molecules in opposite directions?

Antiport Signup and view all the answers

In facilitated diffusion, which substances are typically transported?

Glucose and amino acids Signup and view all the answers

What energy source is used in primary active transport?

ATP hydrolysis Signup and view all the answers

What is the coupling ratio of sodium to potassium ions in the Na+/K+ pump?

3:2 Signup and view all the answers

Which of the following is NOT a characteristic of secondary active transport?

Directly requires ATP Signup and view all the answers

The process of molecules moving from an area of higher concentration to lower concentration is called:

Diffusion Signup and view all the answers

Facilitated diffusion is regulated by which of the following?

Hormones Signup and view all the answers

What is the primary function of the control center in a feedback loop?

Determines a set point for normal range Signup and view all the answers

Which of the following best describes negative feedback loops?

Responses act to counteract the change Signup and view all the answers

Which of the following is an example of a positive feedback loop?

Blood clotting Signup and view all the answers

What happens when the internal environment fails to compensate for disturbances?

Illness or death can occur Signup and view all the answers

Which component of a feedback loop is responsible for detecting changes in the body?

Receptor Signup and view all the answers

What is the main function of the Na+ - K+ pump?

To control cell volume Signup and view all the answers

Which process involves engulfing bacteria and dead tissue by cells?

Phagocytosis Signup and view all the answers

What characterizes exocytosis?

Expulsion of substances from the cell Signup and view all the answers

In the context of osmosis, what is osmotic pressure?

The pressure required to move solute across a semipermeable membrane Signup and view all the answers

Which factor does NOT directly affect the amount of fluid filtered in filtration?

Temperature of the solution Signup and view all the answers

What type of particles pass through a porous membrane during filtration?

Dissolved molecules with smaller diameters than the pores Signup and view all the answers

How does osmotic pressure relate to the number of particles in a solution?

Osmotic pressure is directly proportional to the number of particles Signup and view all the answers

Which option correctly differentiates between pinocytosis and phagocytosis?

Pinocytosis is known as cell drinking, while phagocytosis is cell eating. Signup and view all the answers

What is an example of the passive movement of water through a membrane?

Osmosis Signup and view all the answers

Which statement about filtration is true?

It is driven by a difference in hydrostatic pressure. Signup and view all the answers

Which transport mechanism involves the movement of substances against their concentration gradient?

Primary active transport Signup and view all the answers

What characteristic of the fluid mosaic model describes the arrangement of phospholipids and proteins?

Dynamic and flexible arrangement Signup and view all the answers

Which organelle is primarily responsible for the synthesis of proteins?

Endoplasmic reticulum Signup and view all the answers

What is the primary purpose of homeostasis in a biological system?

To maintain stable internal conditions Signup and view all the answers

Which type of endocytosis involves the ingestion of liquid substances?

Pinocytosis Signup and view all the answers

What is the primary function of the nervous system?

Coordination and response to stimuli Signup and view all the answers

Which organ system is primarily responsible for nutrient absorption?

Digestive system Signup and view all the answers

What characterizes the cardiac cycle during systole?

Contraction of the heart muscles Signup and view all the answers

What is a key role of the plasma membrane?

Cell signaling Signup and view all the answers

Which of the following accurately describes the function of the endocrine system?

Regulates long-term body processes Signup and view all the answers

Which process within cellular respiration produces most of the ATP?

Oxidative phosphorylation Signup and view all the answers

What does selective permeability of the plasma membrane refer to?

Regulating the entry and exit of substances Signup and view all the answers

Which system is primarily engaged in waste elimination?

Excretory system Signup and view all the answers

What type of signals do cells primarily use for cell signaling?

Hormones and neurotransmitters Signup and view all the answers

What is the role of valves in the cardiovascular system?

Control blood flow direction Signup and view all the answers

Study Notes

What is Physiology?

The study of the functions and vital processes of living organisms.
It explains the physical and chemical factors responsible for life's origin, development, and progression.
Physiology helps understand the principles that underlie normal function to cure impairments.
It distinguishes between process and function.

Cell Structure and Function

The cell is the structural and functional unit of life.
The cell membrane (plasma membrane) is a thin, elastic, and semipermeable barrier between the cell and its surroundings.
The cell membrane consists of a lipid bilayer made up of phospholipids and cholesterol.
The lipid bilayer has hydrophilic heads that are exposed to water outside (ECF) and inside (ICF) the cell, and hydrophobic tails that meet in the water-poor interior of the membrane.
The genetic material (DNA) is the hereditary material of the cell.
DNA appears as chromatin in non-dividing cells and condenses to form chromosomes in dividing cells.

Cell Organelles

Mitochondria: The powerhouse of the cell, containing its own DNA (mDNA), RNA, and ribosomes. Produces ATP (high-energy compound).
Endoplasmic Reticulum (ER):
- Smooth ER: Detoxifies drugs and pesticides, absorbs, synthesizes, and transports fats, breaks down glycogen to form glucose.
- Rough ER: Contains ribosomes for protein manufacture.
Ribosomes: The protein factories of the cell, responsible for protein synthesis. Can be either free-floating or attached to the ER.
Golgi Apparatus: Modifies, packages, stores, and transports materials out of the cell. Works with ribosomes and ER.
Lysosomes: Membrane-bound organelles containing digestive enzymes to digest food particles inside or outside the cell.
Cytoskeleton: Provides support for the cell, giving it shape and helping with organelle movement. Consists of small microfilaments and larger microtubules.

Transport Mechanisms

Diffusion: Passive movement of substances from a higher concentration to a lower concentration.
- Factors affecting diffusion: Lipid solubility, Concentration gradient, Surface area, Temperature.
- Inversely related to membrane thickness and molecular weight.
Facilitated diffusion: Passive movement of substances down their concentration gradient with the help of transport proteins. Regulated by hormones.
Active Transport: Requires specific carrier proteins and energy (from ATP hydrolysis) to move substances against their concentration gradient.
- Primary Active Transport: Directly uses ATP for transport. Examples: Na+-K+ pump, Ca2+ pump, H+ pump.
- Secondary Active Transport: Uses the electrochemical gradient created by primary active transport to transport other substances. Example: Sodium-dependent glucose transport.
Na+-K+ Pump: Maintains cell volume and creates an electrochemical gradient across the membrane. pumps three Na+ ions out of the cell and two K+ ions into the cell for every ATP molecule hydrolyzed.
Endocytosis: Transport of large particles into the cell.
- Pinocytosis (Cell Drinking): Engulfment of fluids and small particles.
- Phagocytosis (Cell Eating): Engulfment of bacteria and dead tissue.
Exocytosis: Transport of materials out of the cell by fusing vesicles with the cell membrane.
Filtration: Passive movement of water through a porous membrane due to a pressure difference. Examples: formation of interstitial fluid and glomerular filtrate.
Osmosis: Passive movement of water through a semipermeable membrane from a dilute solution to a concentrated solution.
- Osmotic pressure: Pressure required to prevent water movement from a dilute solution to a concentrated solution.
- Osmoles: Measure of osmotic activity.

Homeostasis

Maintenance of a stable internal environment despite external changes.
Regulated by feedback loops.
Feedback loops: Cycles of events that monitor and adjust body conditions.
- Receptor: Detects changes in the body.
- Control Center: Determines the set point and receives input from the receptor.
- Effectors: Cause the response determined by the control center.
Negative Feedback Loops: Response counteracts the change, stabilizing the internal environment.
- Most feedback loops in the body are negative feedback loops.
Positive Feedback Loops: Response enhances the change, amplifying the initial stimulus. Examples: blood clotting, childbirth.

Human Physiology

Studies the functions of the human body and its various parts.
Integrates knowledge from different bodily systems like the nervous, endocrine, and respiratory systems.
Focuses on maintaining homeostasis, the body's ability to regulate its internal environment despite external changes.
Key processes include metabolism, growth, reproduction, and responding to stimuli.

Cell Physiology

Examines the functions of individual cells and their internal structures (organelles).
Key concepts include:
- Membrane Potentials: The difference in electrical charge across cell membranes, crucial for nerve impulses.
- Cellular Respiration: The process of converting glucose and oxygen into ATP (energy), involving glycolysis, the Krebs cycle, and oxidative phosphorylation.
- Cell Signaling: Communication between cells through hormones, neurotransmitters, and receptors.

Physiological Systems

Nervous System: Includes the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves throughout the body). It's responsible for coordinating, controlling, and responding to stimuli.
Endocrine System: Composed of glands that release hormones into the bloodstream. Regulates long-term bodily processes such as growth and metabolism.
Respiratory System: Responsible for gas exchange, taking in oxygen and releasing carbon dioxide between the body and the environment. This involves lungs, the trachea, and the diaphragm.
Digestive System: Breaks down food into nutrients that can be absorbed by the body. Major parts include the mouth, stomach, intestines, liver, and pancreas.
Excretory System: Eliminates waste and regulates water and electrolytes in the body. This system mainly involves the kidneys and urinary tract.
Musculoskeletal System: Facilitates movement and provides support to the body. It's made up of bones, muscles, and connective tissues.
Immune System: Defends the body against pathogens and diseases. This system includes the lymphatic system and various immune cells.

Cardiovascular Physiology

Focuses on the heart, blood vessels, and the circulation of blood.
Key functions:
- Transporting nutrients, gases, hormones, and waste throughout the body.
- Maintaining blood pressure and regulating body temperature.
- The cardiac cycle consists of systole (heart contraction) and diastole (heart relaxation).
- Blood flow is regulated by valves and autoregulatory mechanisms.

Structure of Plasma Membrane

Composed of a phospholipid bilayer with proteins embedded within it.
Functions:
- Selective Permeability: Regulates what enters and exits the cell.
- Cell Signaling: Receptors on proteins bind to signaling molecules, enabling communication.
Key components:
- Phospholipids: Hydrophilic heads face outwards, hydrophobic tails face inwards.
- Proteins: Integral proteins span the membrane, while peripheral proteins remain on the surface.
- Carbohydrates: These are attached to proteins or lipids and play a role in cell recognition.
The Fluid Mosaic Model describes the dynamic nature and organization of membrane components.

Studying That Suits You

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

Description

This quiz explores the fundamentals of physiology and the intricate details of cell structure and function. It covers essential aspects such as the functions of living organisms, the role of the cell membrane, and the importance of DNA. Test your understanding of how these components contribute to life and its processes.