Cell Membrane and Transport Methods

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Questions and Answers

What is the primary function of the cell membrane?

To facilitate the production of proteins

To generate energy for the cell

To keep the cell contents together and provide protection (correct)

To serve as a storage site for nutrients

Which property of the cell membrane determines its selective permeability?

The presence of cholesterol

The thickness of the membrane

The type of proteins embedded within it

The phospholipid bilayer structure (correct)

What distinguishes active transport from passive transport?

Active transport occurs without the use of energy

Active transport is primarily facilitated by proteins

Active transport can move substances up a concentration gradient (correct)

Active transport depends solely on diffusion

Which type of molecules pass through the cell membrane most easily?

Hydrophobic molecules Signup and view all the answers

What role do proteins play in the cell membrane?

They function as channels and identification markers Signup and view all the answers

What is diffusion in the context of passive transport?

The movement of substances from an area of higher to a lower concentration Signup and view all the answers

What happens during facilitated diffusion?

Transport proteins assist the movement of substances Signup and view all the answers

How thick is the cell membrane?

3/10,000,000 of an inch Signup and view all the answers

What is the primary use of a light microscope?

To examine tissues and cells, typically requiring stains Signup and view all the answers

Which type of microscope is best for viewing the internal structure of solids?

Transmission electron microscope (TEM) Signup and view all the answers

What type of information does a scanning electron microscope (SEM) provide?

Three-dimensional surface features of a specimen Signup and view all the answers

What is a major advantage of using an atomic force microscope (AFM)?

It achieves resolutions better than the optical diffraction limit Signup and view all the answers

Which resolution corresponds to the capability of a light microscope?

0.1µm Signup and view all the answers

What is the role of stains when using a light microscope?

To enhance contrast and visibility of specific cellular components Signup and view all the answers

Which microscope type can generate images at a resolution of about 0.1nm?

Electron microscope Signup and view all the answers

What feature is unique to scanning electron microscopes (SEM)?

Utilization of a focused beam of electrons to scan surfaces Signup and view all the answers

What is the primary purpose of diffusion in the respiratory system?

To move oxygen from the lungs to the bloodstream Signup and view all the answers

What occurs during osmosis?

Water moves from low solute concentration to high solute concentration Signup and view all the answers

Which term describes a solution with a higher concentration of impermeable solutes compared to the cell's interior?

Hypertonic Signup and view all the answers

What best describes the concept of osmotic pressure?

The force attracting water towards an area of higher solute concentration Signup and view all the answers

How does filtration differ from other transport mechanisms?

Filtration relies on pressure to move water and solutes Signup and view all the answers

Which of the following solutions would cause a red blood cell to swell and potentially burst?

Hypotonic solution Signup and view all the answers

What indicates an isotonic solution in relation to a cell?

No net movement of water across the cell membrane Signup and view all the answers

What happens to water molecules during osmosis when concentrations are unbalanced?

Water molecules shift towards areas of higher solute concentration Signup and view all the answers

What are cilia primarily used for in cells?

Moving particles using a wavelike motion Signup and view all the answers

What process is described as the transmission of genetic traits from parent to offspring?

Heredity Signup and view all the answers

What is produced during cellular respiration in the mitochondria?

Energy in the form of ATP Signup and view all the answers

Which component is necessary to make energy for cells during cellular respiration?

Glucose and oxygen Signup and view all the answers

What are the waste products of cellular respiration?

Carbon dioxide and water Signup and view all the answers

What does gene expression involve?

Production of RNA and/or proteins Signup and view all the answers

Which of the following best represents the equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP Signup and view all the answers

What happens to glucose during cellular respiration?

It is transformed into ATP Signup and view all the answers

What is the process by which ATP is produced in cells?

Cellular respiration Signup and view all the answers

What is the primary function of mitosis in eukaryotic cells?

To produce identical daughter cells Signup and view all the answers

During which phase of mitosis do the chromosomes align in the center of the cell?

Metaphase Signup and view all the answers

Which type of microorganism is characterized as a simple one-celled organism without a nucleus?

Bacteria Signup and view all the answers

What can cause disease through the abnormal folding of certain proteins?

Prions Signup and view all the answers

What symptom did Julia experience that indicated a respiratory infection?

Shortness of breath Signup and view all the answers

What type of asexual reproduction do eukaryotic cells undergo?

Mitosis and cytokinesis Signup and view all the answers

What is one way protozoa can cause disease?

Through contaminated food Signup and view all the answers

Study Notes

Cell Membrane

The cell membrane acts as a protective covering and allows materials to enter and exit the cell.
It is selectively permeable, allowing some materials to pass through while blocking others.
It is composed of lipids and proteins, primarily a phospholipid bilayer, which prevents polar molecules from passing through, but allows hydrophobic molecules to pass easily.
Proteins in the membrane function as identification markers and channels for substances to enter the cell.

Transport Methods

Passive transport requires no energy and moves substances down their concentration gradient:
- Diffusion: substances move from areas of high concentration to areas of low concentration.
- Osmosis: water moves across a semipermeable membrane from areas of low solute concentration to areas of high solute concentration.
- Filtration: pressure forces water and dissolved materials across a membrane.
- Facilitated diffusion: a substance moves across a membrane with the help of a transport protein.
Active transport requires energy and moves substances up their concentration gradient.

Microscopy

Light microscopes have a resolution of about 0.1µm and can be used to examine tissues and cells.
Electron microscopes have a resolution of about 0.1nm and are used to view internal structures.
- Scanning electron microscopy (SEM) provides three-dimensional surface images.
- Transmission electron microscopy (TEM) reveals internal structures.
Atomic force microscopy (AFM) has very high resolution and can reveal surface topography.

Osmosis

Osmosis is a type of passive transport involving water movement across a selectively permeable membrane from a low solute concentration to a high solute concentration.
Osmotic pressure is a substance's ability to pull water towards areas of higher concentration.
- Hypertonic solutions have a higher impermeable solute concentration outside the cell than inside.
- Hypotonic solutions have a lower impermeable solute concentration outside the cell than inside.
- Isotonic solutions have equal amounts of impermeable solutes inside and outside the cell.

Cellular Respiration

Cellular respiration is a critical process that allows cells to generate energy from food.
In simple terms, the body digests food, releasing energy.
Glucose, a simple sugar, is the primary source of energy for cells.
During cellular respiration, glucose combines with oxygen in the mitochondria to produce ATP (adenosine triphosphate).
The equation for cellular respiration is: Glucose + Oxygen → Carbon Dioxide + Water + ATP.

Gene Expression

Genes are units of heredity that determine the structure of RNA molecules, which can function independently or produce proteins.
Gene expression is the process of producing RNA and/or proteins from the information stored in DNA.

Asexual Reproduction in Eukaryotic Cells

Asexual reproduction allows cells to create identical copies of themselves, contributing to growth and repair.
Mitosis and cytokinesis are essential processes in eukaryotic asexual reproduction.
Mitosis, the division of genetic material, occurs in four phases: prophase, metaphase, anaphase, and telophase.
Cytokinesis, the division of cytoplasm and organelles, follows mitosis.

Microorganisms: A Summary

Bacteria are simple one-celled organisms that lack a nucleus and organelles.
Viruses are not cells; they require another cell to replicate.
Fungi can be single-celled or multicellular and can cause infections.
Protozoa are single-celled organisms that can cause disease.
Prions are misfolded proteins that cause disease.

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Description

Explore the structure and function of the cell membrane, including its role in selective permeability and transport methods. This quiz covers key concepts such as diffusion, osmosis, and facilitated diffusion, explaining how substances move in and out of the cell. Test your understanding of these fundamental biological processes!