Cell Organelles and Immune System Overview

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Questions and Answers

What is the main function of ribosomes in a cell?

To create lipids for the cell

To regulate what enters and exits the cell

To make proteins (correct)

To provide structural support

What structure serves as the control center of eukaryotic cells?

Rough Endoplasmic Reticulum

Plasma membrane

Nucleus (correct)

Cytoplasm

Which organelle is responsible for energy production in eukaryotic cells?

Mitochondria (correct)

Lysosome

Golgi apparatus

Nucleolus

What is the primary function of the Golgi apparatus?

To package and distribute proteins Signup and view all the answers

What role does the cytoskeleton play in a cell?

Providing structural support and transporting materials Signup and view all the answers

Which organelle is primarily involved in detoxifying harmful substances in eukaryotic cells?

Smooth Endoplasmic Reticulum Signup and view all the answers

What is the primary content found within the nucleolus?

RNA and proteins used to make ribosomes Signup and view all the answers

How does the plasma membrane contribute to cellular function?

By controlling the entry and exit of substances Signup and view all the answers

What characteristic of the phosphate group in phospholipids allows it to interact with water?

It is polar Signup and view all the answers

What structure does the lipid bilayer primarily form in cell membranes?

Two layers of phospholipids Signup and view all the answers

Why do polar or hydrophilic substances generally not pass through the cell membrane easily?

Because they are repelled by lipid tails Signup and view all the answers

What is the primary role of antibodies in the immune response?

To bind to specific antigens and attract phagocytes Signup and view all the answers

What term describes the constant movement of phospholipids and proteins within the cell membrane?

Fluid Mosaic Model Signup and view all the answers

Which of the following correctly describes the role of T cells in the immune system?

They target and eliminate infected or abnormal cells Signup and view all the answers

Which type of transport requires energy to move substances across the cell membrane?

Active Transport Signup and view all the answers

What are the four classic signs of inflammation?

Swelling, Heat, Pain, Redness Signup and view all the answers

What is the primary function of cholesterol in the cell membrane?

To maintain membrane fluidity Signup and view all the answers

How does innate immunity differ from adaptive immunity?

Innate immunity provides general protection, while adaptive involves memory Signup and view all the answers

What is the primary function of phagocytes like macrophages and neutrophils?

To engulf and destroy bacteria and other foreign materials Signup and view all the answers

What happens to particles during diffusion?

They move from high to low concentration Signup and view all the answers

Which of the following is NOT a passive transport mechanism?

Active Transport Signup and view all the answers

Which component of the immune system is not involved in the adaptive phase?

Phagocytes Signup and view all the answers

How do skin and mucous membranes act as the first line of defense in the immune system?

They have physical barriers and produce substances that trap invaders Signup and view all the answers

What is the significance of the low pH and high salt content of skin?

They serve as deterrents to bacterial growth Signup and view all the answers

What defines passive immunity?

Immunity gained through the transfer of antibodies from another source Signup and view all the answers

Which of the following is primarily responsible for memory in the adaptive immune system?

B cells and T cells Signup and view all the answers

What is the primary function of endocytosis?

Taking materials into the cell Signup and view all the answers

In what scenario does negative feedback occur in the body?

When the body temperature rises to excess, prompting sweating Signup and view all the answers

Which of the following processes is an example of positive feedback?

The onset of labor contractions during childbirth Signup and view all the answers

What does homeostasis refer to in the context of cell regulation?

The maintenance of a stable internal environment Signup and view all the answers

What is the role of oxytocin during childbirth?

It stimulates contractions to facilitate delivery Signup and view all the answers

How does the body regulate blood glucose levels through hormones?

By using insulin to lower glucose levels and glucagon to increase them Signup and view all the answers

What triggers the process of lactation in response to an infant?

Milk production increases until the baby stops suckling Signup and view all the answers

Which of the following responses is an example of negative feedback in temperature regulation?

Body temperature drops, leading to shivering Signup and view all the answers

What role does ethylene play in fruit ripening?

It binds to receptors and triggers ripening genes. Signup and view all the answers

Which component of the neuron sends signals away from the cell body?

Axon Signup and view all the answers

How does an action potential begin in a neuron?

By sodium ions entering the cell. Signup and view all the answers

What is the function of neurotransmitters?

To facilitate signal transmission across the synapse. Signup and view all the answers

What distinguishes steroid hormones from non-steroidal hormones?

Steroid hormones can cross the membrane, whereas non-steroidal hormones cannot. Signup and view all the answers

What is the primary function of the sodium-potassium pump in neurons?

To reset the voltage of the membrane after a signal has passed. Signup and view all the answers

What is quorum sensing in bacteria related to?

Starting or stopping certain activities based on group density. Signup and view all the answers

What is one role of the peripheral nervous system?

To connect the brain and spinal cord to the rest of the body. Signup and view all the answers

What initiates the propagation of a signal down the axon of a neuron?

The opening of sodium ion channels. Signup and view all the answers

What is a key feature of how non-steroidal hormones communicate within cells?

They activate membrane proteins that transmit signals to the inside of the cell. Signup and view all the answers

Study Notes

Cell Organelles

Cell membrane surrounds the cell, made of phospholipids
Cytoplasm is the jelly-like fluid inside the cell
Ribosomes are small proteins that make proteins for the cell
Nucleoid is the area where DNA gathers for prokaryotes only
Nucleus contains the DNA in eukaryotes only
Nucleolus is a dark area inside the nucleus where ribosomes are made
Rough ER is connected to the nucleus and has ribosomes on its surface. It makes and processes proteins
Smooth ER is connected to the rough ER but has no ribosomes. It makes lipids and detoxifies
Golgi apparatus is a stack of membranes that receives, labels, and sends proteins from the rough ER.
Mitochondria are organelles responsible for making ATP (energy) in eukaryotes
Lysosomes are small spheres containing acids and digestive enzymes found in animal cells
Cytoskeleton is a network of proteins that provide structure and support to cells, also acts as a transport system

Immune System

Immune cells recognize foreign invaders by their antigens
Innate immunity is a rapid and nonspecific response
The first line of defense of innate immunity is the skin and mucous membranes
- Skin has a low pH, high salt content, is dry, and has a natural microbiome
- Mucous traps invaders
The second line of defense of innate immunity includes:
- Inflammation: redness, swelling, heat, and pain that prevent the spread of invaders
- Fever: a systemic response that helps fight invaders
- Phagocytes: macrophages and neutrophils that engulf bacteria and other foreign invaders
Adaptive immunity is acquired after exposure to disease
Antibodies are proteins that identify specific antigens on invaders
T cells and B cells are specialized immune cells that produce antibodies and create immunity
- B cells make antibodies
- T cells target infected cells

Cell Membrane Study Guide

The cell membrane is made of phospholipids, membrane proteins, carbohydrates, and cholesterol
Phospholipids are fats with a polar, hydrophilic head and two nonpolar, hydrophobic tails. They form a bilayer with the heads facing the extracellular and intracellular spaces.
Membrane proteins are responsible for the transport of materials in and out of the cell
Carbohydrates act as signals on the membrane
Cholesterol helps keep the membrane fluid
The cell membrane is semi-permeable, meaning it allows some materials to pass through but not others.
The fluid mosaic model says that the membrane proteins and phospholipids are constantly moving.

Diffusion, Osmosis, Active Transport

Diffusion: The movement of particles from an area of high concentration to an area of low concentration.
Osmosis: The movement of water across a semi-permeable membrane to balance the concentration of solutes
Active Transport: Requires energy to move particles against their concentration gradient.
- Using a protein: Transport proteins move specific materials in or out of the cell
- Bulk Transport: Vesicles move larger molecules in or out of the cell
  - Endocytosis: Takes materials into the cell
  - Exocytosis: Releases materials out of the cell

Homeostasis

The cell/body maintains a steady state for things like temperature, water content.
Negative Feedback: A signal that causes the cell to counter something undesirable. Examples:
- Temperature regulation: shivering when cold, sweating when hot
- Blood glucose regulation: insulin and glucagon
- Hormone regulation: testosterone and estrogen
Positive Feedback: A signal that causes the body to continue an action or strengthen a stimulus. Examples:
- Childbirth: the baby's pressure on the cervix triggers oxytocin release
- Lactation: baby suckling triggers prolactin and oxytocin release
- Fruit ripening: ethylene gas triggers ripening genes

The Nervous System

The central nervous system consists of the brain and spinal cord
The peripheral nervous system consists of all the nerves in the body.
Neurons are brain cells that send signals. They are composed of:
- Dendrites: receive signals
- Axon: sends signals
- Myelin sheaths: protect the axon and make signals travel faster
Action potentials: are how neurons transmit signals. They are caused by the opening of voltage-gated sodium channels, creating a positive charge that propagates down the axon.
Neurotransmitters: chemical messengers released from the end of an axon into the synapse. They bind to receptors on the next cell to continue the signal.

Endocrine System

Works with the nervous system to send long-distance chemical signals
Hormones: Long-distance signal molecules that travel through the bloodstream to target cells.
Steroid (Lipid) Hormones: Can cross the cell membrane and bind to proteins inside the cell
Non-Steroidal (Hydrophilic) Hormones: Cannot cross the membrane so they bind to membrane proteins, which trigger a signal cascade inside the cell.

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Description

Explore the essential components of cell organelles and their functions, as well as an introduction to the immune system. This quiz delves into the structures responsible for maintaining cell health and the body's defense mechanisms. Test your knowledge and understanding of these vital biological concepts.