Cell Structure and Microscopy Quiz

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Questions and Answers

What is the primary function of chloroplasts in plant cells?

Protein synthesis

Photosynthesis (correct)

Storage of organic compounds

Cell division

Which structure is unique to animal cells?

Central vacuole

Centriole (correct)

Cell wall

Chloroplasts

What role does the large central vacuole play in plant cells?

Photosynthesis

Storage of nutrients and waste products (correct)

DNA replication

Respiration

How do plasmodesmata function in plant cells?

They allow communication between neighboring cells. Signup and view all the answers

What does the Golgi apparatus primarily function in?

Protein sorting and distribution Signup and view all the answers

Which of the following cell organelles is considered to be the most abundant in cells?

Mitochondria Signup and view all the answers

What is the composition of the plant cell wall primarily made of?

Cellulose Signup and view all the answers

What structure in the nucleus is involved in the production of ribosomes?

Nucleolus Signup and view all the answers

What is the basic unit of length in the International System of Units (SI units)?

Meter Signup and view all the answers

Which of the following is the correct representation of one millionth of a meter?

10^-6 Signup and view all the answers

What does magnification represent in microscopy?

The number of times larger an image is compared to the real object Signup and view all the answers

What is resolution in the context of microscopy?

The ability to distinguish between two separate points Signup and view all the answers

What must be done before determining the size of a specimen using an eyepiece graticule?

Calibrate the eyepiece graticule Signup and view all the answers

When using a stage micrometer, what does the equation 'Stage micrometer scale = Eyepiece graticule division' help determine?

The actual size of the specimen Signup and view all the answers

Which type of microscope provides a maximum resolution of 200 nm?

Light microscope Signup and view all the answers

What happens to wavelengths as energy increases in the electromagnetic spectrum?

Wavelengths become shorter Signup and view all the answers

What is a key structural difference between prokaryotic and eukaryotic DNA?

Eukaryotic DNA is linear and associated with proteins, forming chromosomes. Signup and view all the answers

Which component is NOT found in prokaryotic cells?

80s ribosomes Signup and view all the answers

What role do pili play in prokaryotic cells?

They assist in the attachment to surfaces. Signup and view all the answers

What is the main reason viruses are classified as parasitic?

They must infect living cells to replicate. Signup and view all the answers

Which of the following correctly describes eukaryotic cells?

They can measure up to 40 μm in diameter. Signup and view all the answers

What feature distinguishes viruses from bacteria?

Viruses can only reproduce inside living cells. Signup and view all the answers

What do the ribosomes of prokaryotic cells consist of?

70s subunits Signup and view all the answers

What is the function of the flagellum in prokaryotic cells?

It is involved in locomotion. Signup and view all the answers

What happens to an object smaller than half the wavelength of radiation used to view it?

It cannot be separated from nearby objects. Signup and view all the answers

What is the primary function of the nucleus in a cell?

To control enzyme production and regulate cell functions. Signup and view all the answers

What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

Rough ER has ribosomes, while smooth ER does not. Signup and view all the answers

What role does the Golgi apparatus play in cellular processes?

It collects, processes, and sorts molecules for transport. Signup and view all the answers

What is the primary function of lysosomes in a cell?

To digest unwanted structures within the cell. Signup and view all the answers

How do microtubules contribute to cell structure?

They are long, rigid tubes that make up the cytoskeleton. Signup and view all the answers

What is the function of centrioles in a cell?

To grow spindle fibers used for nuclear division. Signup and view all the answers

What are the main components found in cilia and flagella?

Microtubules covered by an extension of the plasma membrane. Signup and view all the answers

According to the endosymbiont theory, what unique characteristic do mitochondria and chloroplasts share?

They contain smaller ribosomes similar to those found in bacteria. Signup and view all the answers

What is the diameter of a typical mitochondrion?

Around 1 μm. Signup and view all the answers

Study Notes

Cell Structure - Microscopy

Light microscopy is used to view cells.
Components of a light microscope include: body tube, revolving nosepiece, objectives, stage clips, diaphragm, light source, stage, coarse adjustment knob, fine adjustment knob, and base, ocular lens (eyepiece).
Light microscopes utilize light to illuminate the specimen and form an image.

Cell Structure - Photomicrographs

Photomicrographs are images of cells taken using a microscope.
Examples shown include plant cells, cheek cells, and guard cells.

Cell Structure - Plant vs. Animal Cells

Plant and animal cells share similarities but also have differences in structures.
Structures found in plant cells but not animal cells include a cell wall, chloroplasts, and a large central vacuole.
Structures found in animal cells but not plant cells include centrioles.
Both plant and animal cells have cell membranes, cytoplasm, mitochondria, and Golgi apparatus.
Both types of cells use staining techniques to highlight cell structures.

Cell Structure - Measuring Cells

Measuring objects in microscopy uses units like millimeters (mm), micrometers (µm), and nanometers (nm).
The international system uses the meter (m), as its basic unit of length.

Cell Structure - Magnification and Resolution

Magnification is the increase in size of an image as compared to the size of the specimen.
Resolution is the ability to distinguish two points that are extremely close as separate.
Units for magnification and resolution need to be consistent ( e.g., nm for both ).
A light microscope has a maximum resolution of 200nm.

Cell Structure - Measuring Cells with Graticules

Eye-piece graticules are transparent scales placed in the eyepiece of a microscope to measure cell and organelle sizes.
A stage micrometer scale is used to calibrate the eyepiece graticule. This is done by placing the stage micrometer on the stage of the microscope, focusing, and aligning the scales.
The value of the eyepiece graticule division must be calculated using the scale values of the stage micrometer.
To measure a sample, determine how many divisions are present in the specimen and use the calculated value to find the actual specimen size.

Cell Structure - Electron Microscopy

Transmission electron microscopes (TEM) and scanning electron microscopes (SEM) provide higher resolution than light microscopes to view cell ultrastructures.

Cell Structure - The Electromagnetic Spectrum

The electromagnetic spectrum is the range of wavelengths of electromagnetic radiation.
The shorter the wavelength, the higher the energy of the radiation.
Microscopes use specific forms of electromagnetic radiation.

Cell Structure - Cell Ultrastructure

Ultrastructure refers to the detailed structures revealed by the electron microscope.
Cell components that are viewed by the electron microscope include plant cells with peroxisomes, mitochondria, golgi complex, microfilm filaments, vacuoles, microtubules, chloroplasts, cytoplasm, ribosomes, smooth endoplasmic reticulum, rough endoplasmic reticulum, plasma membrane, cell wall, and nucleus.
Animal cells contain similar structures, but there are differences (e.g., centrioles, lysosomes ).

Cell Structure - Nucleus

Nucleus is a double-membraned, rounded organelle embedded in the cytoplasm.
The nucleus controls cell division and regulation of chemical changes inside the cell, to determine its role.
The nucleus holds chromatin, and chromosomes, which play a role in cell division and inheritance

Cell Structure - Endoplasmic Reticulum

The Endoplasmic Reticulum (ER) is an extensive membrane system in the cytoplasm that forms flattened sacs, called cisternae.
The Rough ER contains ribosomes for protein production and transport.
The Smooth ER makes lipids and steroids.

Cell Structure - Golgi Body

The Golgi body is a stack of flattened sacs formed from vesicles budding off the ER.
The Golgi body sorts molecules being transported to other parts of the cell.
Lysosomes are formed from the Golgi body.

Cell Structure - Lysosomes

Lysosomes are spherical sacs with a single membrane.
They contain hydrolytic enzymes that digest unwanted structures within the cell or old organelles. They can digest entire cells or bacteria.

Cell Structure - Mitochondrion

Mitochondria are surrounded by a double membrane.
They are about 1 micrometer in size, and contain cristae, folded inner membranes.
Mitochondria release energy from food substances through cellular respiration. They convert that energy into ATP.
They are involved in lipid synthesis.

Cell Structure - Microtubules

Microtubules are long tubular structures in the cytoplasm, forming the cell's cytoskeleton.
They are made up of tubulin protein that forms a cylinder with a hollow center.
They are part of the microtubule organizing centers (MTOCs).

Cell Structure - Centrioles

Centrioles are hollow cylinders formed from microtubules to grow spindle fibres for nuclear division.
They are found near the animal cell nucleus.
Each centriole consists of nine triplets of microtubules.

Cell Structure - Cilia, Flagella & Microvilli

Microvilli are finger-like extensions of the cell membrane that increase the surface area for absorption.
Cilia and flagella are long, thin extensions covered by plasma membrane and contain microtubules for movement.
Flagella are typically fewer in number than cilia.

Cell Structure - The Endosymbiont Theory

Mitochondria and chloroplasts are thought to have originated from ancient bacteria that were engulfed by other cells.
They contain their own DNA and ribosomes, similar to bacteria.

Cell Structure - Two Fundamentally Different Cell Types

Prokaryotic cells do not contain a nucleus. Examples include bacteria.
Eukaryotic cells contain a nucleus. Examples include plants, animals, fungi, and protists.
Prokaryotes cell walls contain murein, while eukaryotic cells may have different types of cell walls.

Cell Structure - Prokaryotic Cell

Pili help with attachment to other cells for reproduction.
Cell walls contain the murein (peptidoglycan) protein.
Flagella are used for locomotion.
Plasmids are small, circular DNA.
Capsules are for additional protection.
Ribosomes are 70s.

Cell Structure - Viruses

Viruses are smaller than bacteria and at the boundary between living and non-living organisms.
Viruses consist of a self-replicating molecule of DNA or RNA (genetic code) and a protein coat (capsid).
Viruses range in size from 20-300 nm.
Viruses are parasitic, needing a host cell to reproduce. They infect other living cells.

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Description

This quiz covers essential concepts of cell structure, focusing on light microscopy and the differences between plant and animal cells. It explores the components of light microscopes, the importance of photomicrographs, and unique cellular structures of each type of cell. Test your understanding of these fundamental biological concepts.