Cell Biology, Microscopy, and Calculations Review

Flashcards covering cell structure, prokaryotic and eukaryotic distinctions, plant and animal cell organelles, microscopy principles, and mathematical calculations.

What is the defining characteristic of eukaryotic cells?

They contain membrane-bound organelles, in particular a nucleus enclosing their genetic material.

How is genetic material arranged in a prokaryotic cell?

It is not enclosed in a nucleus; it consists of a single DNA loop free in the cytoplasm, and may include small rings of DNA called plasmids.

What are plasmids in bacterial cells?

Small rings of DNA that are separate from the main DNA loop.

Which groups of organisms are composed of eukaryotic cells?

Plants, animals, and fungi (including yeast).

According to the lecture notes, which two subcellular structures are present in eukaryotic cells but absent in prokaryotic cells?

Nucleus and mitochondria.

Besides cytoplasm and a cell membrane, name three structural features found in bacterial cells.

Cell wall, plasmids, and a protective capsule (or flagellum).

What is the function of the nucleus in a cell?

Controls the activities of the cell and contains the DNA.

What is the function of the cell membrane?

Controls the movement of substances in and out of the cell.

What is the function of mitochondria?

To release energy through aerobic respiration.

What is the function of ribosomes?

They are the site of protein synthesis.

What occurs in the cytoplasm of a cell?

Chemical reactions occur here, controlled by enzymes.

What material is a plant cell wall made of, and what is its function?

It is made of cellulose, and it strengthens and supports the cell.

What is the function of chloroplasts in plant cells?

They are the site of photosynthesis, absorbing light energy for the process.

What does the permanent vacuole contain, and what is its function in a plant cell?

It contains cell sap and helps to provide structure to the plant by keeping the cell turgid.

Which three subcellular structures are found in plant cells but NOT in animal cells?

Chloroplasts, permanent vacuole, and cellulose cell wall.

What is a microscope?

A tool used to view very small objects, such as cells, micro organisms, and large molecules.

How is magnification defined in microscopy?

A measure of how much bigger an object appears.

How is resolution defined in microscopy?

A measure of the amount of detail which can be seen.

How do electron microscopes compare to light microscopes regarding magnification and resolution?

Electron microscopes have much higher magnification and higher resolving power (resolution) than light microscopes.

Why has electron microscopy enabled biologists to study sub-cellular structures like ribosomes and mitochondria in finer detail?

Because electron microscopes offer higher magnification and higher resolution than light microscopes.

What is the function of the eyepiece lens on a light microscope?

It is the lens that you look through to view the specimen.

What is the function of the objective lens on a light microscope?

It magnifies the image of the specimen and can be changed to alter magnification.

What is the function of the stage on a light microscope?

It is where the slide is placed.

What is the function of the focus knob on a light microscope?

Used to focus the image and make it clear.

In science problem-solving, what does the method acronym ESRA stand for?

Equation, Substitute, Re-arrange, Answer.

What formula is used to calculate the total magnification of a light microscope?

$$\text{Total magnification} = \text{eyepiece lens} \times \text{objective lens}$$

What formula links image size ($I$), actual size ($A$), and magnification ($M$)?

$$I = A \times M$$

How many micrometres ($\mu\text{m}$) are in $1\,\text{mm}$?

$$1000\,\mu\text{m}$$

If a microscope has an eyepiece lens of $10\times$ and an objective lens of $40\times$, what is the total magnification?

$$400\times$$

If an onion cell has an actual size of $10\,\mu\text{m}$ and is viewed under $200\times$ magnification, what is its image size?

$$2000\,\mu\text{m}$$