Human Cell Biology Overview

Questions and Answers

There are _______ that vary in shape and size.

75 trillion

What are the main parts of a composite cell?

nucleus, cytoplasm, and cell membrane

What are organelles?

specialized structures that perform specific functions

What is the liquid in cytoplasm called?

cytosol Signup and view all the answers

What does the cell (plasma) membrane do?

Regulates the movement of substances in cell, participates in signal transduction, sends messages inside, and helps cells adhere to other cells. Signup and view all the answers

What are the general characteristics of the cell membrane?

Thin and selectively permeable, complex surface. Signup and view all the answers

What is the surface model of the cell membrane called?

fluid mosaic model Signup and view all the answers

What is the basic framework of the cell membrane?

A double layer of phospholipids with fatty acid tails turned inward. Signup and view all the answers

What molecules can pass through the cell membrane?

Anything soluble in lipids, such as gases and steroid hormones. Signup and view all the answers

What things cannot pass through the cell membrane?

Water-soluble molecules, sugars, amino acids, ions, large proteins, nucleic acids. Signup and view all the answers

What strengthens the cell membrane?

Cholesterol Signup and view all the answers

What makes the membrane less permeable?

Cholesterol Signup and view all the answers

What are the types of proteins in the membrane?

Transmembrane (integral proteins) and peripheral membrane proteins. Signup and view all the answers

What are protein receptors responsible for?

Starting signal transduction. Signup and view all the answers

Proteins help with the ______ of molecules and ions.

passage Signup and view all the answers

What happens when Na channels malfunction?

Hyperkalemia Signup and view all the answers

What happens when Cl channels malfunction?

Cystic fibrosis Signup and view all the answers

Proteins _______ supportive rods and tubules.

anchor Signup and view all the answers

What do glycoproteins help with?

Cell identification Signup and view all the answers

What are cellular adhesion molecules?

Help determine interaction with other cells. Signup and view all the answers

What does the cytoplasm consist of?

Cytosol, cytoskeleton, networks of membranes, and organelles. Signup and view all the answers

What is the endoplasmic reticulum made up of?

Membranes, flattened sacs, and vesicles. Signup and view all the answers

What is the transport system inside the cell?

The ER, which connects to the cell and nuclear membrane. Signup and view all the answers

What is rough ER characterized by?

Having ribosomes; functions in protein synthesis. Signup and view all the answers

What is smooth ER characterized by?

Without ribosomes; functions in lipid synthesis. Signup and view all the answers

What are ribosomes composed of?

Protein and RNA Signup and view all the answers

What gives structural support and enzymes for RNA molecules in protein synthesis?

Ribosomes Signup and view all the answers

What is the Golgi apparatus composed of?

Flattened sacs Signup and view all the answers

The Golgi apparatus can be compared to what?

FedEx Signup and view all the answers

The ER can be compared to what?

The factory Signup and view all the answers

What refines, packages, modifies, and delivers proteins?

Golgi apparatus Signup and view all the answers

Vesicles formed on the ER travel to _______.

Golgi apparatus Signup and view all the answers

The vesicles join to the?

Cistern Signup and view all the answers

What is a transport vesicle?

Have destination inside cell, components, enzymes. Signup and view all the answers

What is a membrane vesicle?

Inserts proteins into the cell membrane. Signup and view all the answers

What are secretory vesicles?

Insulin, puts things in membrane, goes out. Signup and view all the answers

What is vesicle trafficking?

Vesicles may carry chemicals through the cell. Signup and view all the answers

What is the powerhouse of the cell?

Mitochondria Signup and view all the answers

What are double membrane sacs?

Mitochondria Signup and view all the answers

How does mitochondria reproduce?

By dividing Signup and view all the answers

What has enzymes needed for aerobic respiration?

Mitochondria Signup and view all the answers

What is the inner membrane of the mitochondria folded into?

Cristae Signup and view all the answers

What holds the enzymes to make ATP?

Cristae Signup and view all the answers

Mitochondria has _____?

Its own DNA Signup and view all the answers

Mitochondria's DNA is?

Circular Signup and view all the answers

What are the garbage disposals of the cell?

Lysosomes Signup and view all the answers

Lysosomes and peroxisomes are ______ bound vesicles.

Membrane Signup and view all the answers

What do lysosomes contain?

Digestive enzymes to break up old cell components and bacteria. Signup and view all the answers

What contains enzymes that function in the synthesis of bile acids, breakdown of lipids, degradation of rare biochemicals, and detoxification of alcohol?

Peroxisomes Signup and view all the answers

Peroxisomes are abundant in which organs?

Kidney and liver Signup and view all the answers

What are the thin threadlike structures that form the cytoskeleton of the cell?

Microfilaments and microtubules Signup and view all the answers

Microfilaments are?

Actin Signup and view all the answers

What does actin do?

Cause various cellular movements in periphery. Signup and view all the answers

Microtubules are?

Tubulin Signup and view all the answers

What is tubulin?

Helical hollow tube found in cilia and flagella. Signup and view all the answers

What is a centrosome?

Made of two hollow cylinders called centrioles, near nucleus. Signup and view all the answers

Centrosomes are made of?

Microtubules in nine groups of 3. Signup and view all the answers

What function do centrosomes serve during mitosis?

Separation of chromosomes. Signup and view all the answers

What are cilia and flagella?

Motile extensions. Signup and view all the answers

Cilia and flagella are microtubules in what arrangement?

9 and 2 arrangement. Signup and view all the answers

What are cilia?

Shorter and abundant on free surface of certain epithelial cells that help move things along the surface. Signup and view all the answers

What is a flagellum?

Long and whip-like, only found in sperm cells in humans. Signup and view all the answers

What are vesicles?

Form from part of the cell membrane or organelles and store materials. Signup and view all the answers

What houses DNA?

Cell nucleus Signup and view all the answers

The cell nucleus is bounded by?

A double layer nuclear membrane (envelope). Signup and view all the answers

The cell nucleus has large nuclear pores made of proteins that?

Allow the passage of certain substances. Signup and view all the answers

What is the fluid inside the cell nucleus called?

Nucleoplasm Signup and view all the answers

What is the nucleolus made of?

RNA and proteins. Signup and view all the answers

What is the site of ribosome production?

Nucleolus Signup and view all the answers

Chromatin is made of?

Loosely coiled fibers of protein and DNA. Signup and view all the answers

What does chromatin do in cell division?

Forms chromosomes. Signup and view all the answers

Where is chromatin found?

The cell nucleus. Signup and view all the answers

What are pluripotent cells?

Can become anything. Signup and view all the answers

What are multipotent cells?

Cannot become anything. Signup and view all the answers

What does the cell membrane control?

What passes into the cell. Signup and view all the answers

Movement through cells can be?

Passive or active. Signup and view all the answers

Passive transport does?

Not require energy. Signup and view all the answers

Active transport does?

Require energy. Signup and view all the answers

What are the forms of passive movements?

Diffusion, facilitated diffusion, osmosis, and filtration. Signup and view all the answers

What are the forms of active movements?

Active transport, endocytosis, and exocytosis. Signup and view all the answers

Diffusion is the random?

Motions of molecules. Signup and view all the answers

What involves movement of molecules from an area of greater concentration to one of lesser concentration until equilibrium occurs?

Diffusion. Signup and view all the answers

What moves down concentration gradient?

Diffusion. Signup and view all the answers

Diffusion depends on two things:

Permeability of substance and concentration gradient. Signup and view all the answers

What enables oxygen and carbon dioxide to be exchanged between air and blood in the lungs and between blood and cells?

Diffusion. Signup and view all the answers

What uses membrane proteins as carriers to move molecules across the cell membrane?

Facilitated diffusion. Signup and view all the answers

What are examples of facilitated diffusion?

Ion channels, glucose or amino acids, change carrier protein shape to move to other side. Signup and view all the answers

What moves high to low—number of carrier molecules limits the rate?

Facilitated diffusion. Signup and view all the answers

What is diffusion in which water moves from an area of greater concentration across a selectively permeable membrane to an area of lower concentration?

Osmosis. Signup and view all the answers

What is the solvent in osmosis?

Can move through. Signup and view all the answers

What is the solute in osmosis?

Cannot move through. Signup and view all the answers

Osmotic pressure of a solution depends on?

The concentration of its solute particles. Signup and view all the answers

What happens when there are higher solutes?

Higher pressure. Signup and view all the answers

What happens when there are lower solutes?

Lower pressure. Signup and view all the answers

What is a solution with the same osmotic pressure?

Isotonic. Signup and view all the answers

What is a solution with higher solute?

Hypertonic. Signup and view all the answers

What can hypertonic solutions cause?

Crenation. Signup and view all the answers

What is a solution with lower solute?

Hypotonic. Signup and view all the answers

What can hypotonic solutions cause?

Hemolysis. Signup and view all the answers

What is filtration?

A movement of small molecules through membranes by hydrostatic pressure; larger molecules cannot. Signup and view all the answers

Study Notes

General Cell Overview

Approximately 75 trillion cells vary in shape and size within the human body.
Composite cells consist of three main parts: nucleus, cytoplasm, and cell membrane.

Organelle Functions

Organelles are specialized structures performing specific cellular functions.
The cytoplasm contains cytosol, cytoskeleton, networks of membranes, and organelles.

Cell Membrane Characteristics

The plasma membrane is thin, selectively permeable, and has a complex surface described by the fluid mosaic model.
It consists of a double layer of phospholipids with fatty acid tails facing inward.
Molecules that can pass include gases and lipid-soluble substances; water-soluble molecules and large proteins cannot.

Membrane Proteins and Functions

Membrane proteins include transmembrane and peripheral proteins which assist in signal transduction and molecule passage.
Cholesterol strengthens the membrane and makes it less permeable.
Glycoproteins aid in cell identification and cellular adhesion molecules determine interactions with other cells.

Endoplasmic Reticulum (ER)

The ER serves as the transport system within the cell, connecting to the cell and nuclear membranes.
Rough ER contains ribosomes and synthesizes proteins; Smooth ER lacks ribosomes and synthesizes lipids.

Ribosomes and Protein Synthesis

Ribosomes are made of protein and RNA, providing structural support during protein synthesis.
The Golgi apparatus refines, packages, modifies, and delivers proteins, likened to FedEx.

Mitochondria

Known as the powerhouse of the cell, mitochondria have a double membrane, reproduce by division, and contain enzymes for aerobic respiration.
The inner membrane is folded into cristae, which hold enzymes for ATP production and mitochondria possess circular DNA.

Lysosomes and Peroxisomes

Lysosomes are membrane-bound vesicles containing digestive enzymes for cellular debris and bacteria breakdown.
Peroxisomes contain enzymes for synthesizing bile acids and detoxification, abundant in kidney and liver cells.

Cytoskeleton Structure

Microfilaments (actin) support cellular movement while microtubules (tubulin) are found in cilia and flagella.
Centrosomes, composed of centrioles, assist in chromosome separation during mitosis.

Cellular Movement

Movement through cells can be passive or active. Passive movement does not require energy, while active movement does.
Forms of passive movement include diffusion, facilitated diffusion, osmosis, and filtration.

Diffusion and Osmosis

Diffusion involves the random motion of molecules from higher to lower concentration until equilibrium.
Osmosis is the movement of water across a selectively permeable membrane, where the solvent can move but the solute cannot.

Solutions and Osmotic Pressure

Solutions with the same osmotic pressure are isotonic; hypertonic solutions have higher solute concentration leading to crenation, while hypotonic solutions have lower concentration, causing hemolysis.

Filtration

Filtration is the movement of small molecules through membranes driven by hydrostatic pressure, with larger molecules unable to pass.

Studying That Suits You

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

Description

Explore the fascinating structure and functions of human cells with this quiz. Learn about organelles, cell membranes, and the roles of various proteins in cellular processes. Test your knowledge on the essential components that make up cells and how they interact within the human body.