Cell Structure and Function Quiz
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Questions and Answers

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

  • Energy production
  • DNA storage and control of cell activities (correct)
  • Protein modification
  • Lipid synthesis

Which of the following organelles is involved in the synthesis of lipids?

  • Smooth endoplasmic reticulum (correct)
  • Golgi apparatus
  • Rough endoplasmic reticulum
  • Lysosomes

What type of cell organelle is the Golgi apparatus?

  • Ribosome assembly area
  • Organelle that produces ATP
  • Site of photosynthesis
  • Membrane-bound structure for protein and lipid modification (correct)

What role do ribosomes play in a eukaryotic cell?

<p>Translation of RNA into protein (A)</p> Signup and view all the answers

What structure within the nucleus is specifically responsible for ribosome production?

<p>Nucleolus (A)</p> Signup and view all the answers

What is the primary purpose of lysosomes in a eukaryotic cell?

<p>Digestion of waste materials and old organelles (D)</p> Signup and view all the answers

Which organelle is known as the powerhouse of the cell?

<p>Mitochondria (C)</p> Signup and view all the answers

What is the main function of chloroplasts in eukaryotic cells?

<p>Photosynthesis (B)</p> Signup and view all the answers

What is a primary disadvantage of using a Transmission Electron Microscope (TEM)?

<p>Samples need to be fixed and placed in a vacuum. (C)</p> Signup and view all the answers

How does the maximum magnification of a Scanning Electron Microscope (SEM) compare to that of a TEM?

<p>TEM has a higher maximum magnification than SEM. (D)</p> Signup and view all the answers

Which of the following correctly defines magnification?

<p>The ratio of the viewed image size to the original object size. (C)</p> Signup and view all the answers

What is necessary before using the eyepiece graticule to measure a specimen?

<p>You must calibrate the eyepiece graticule with the stage micrometer. (C)</p> Signup and view all the answers

What is a significant feature of the images produced by a Scanning Electron Microscope (SEM)?

<p>They can create three-dimensional representations. (C)</p> Signup and view all the answers

What step is essential when preparing a specimen for viewing with an optical microscope?

<p>Applying a drop of stain to enhance contrast. (A)</p> Signup and view all the answers

What is the maximum resolution of a TEM?

<p>0.0002 μm (C)</p> Signup and view all the answers

Which process is used to determine the size of a specimen under a microscope?

<p>Aligning the eyepiece graticule and stage micrometer. (A)</p> Signup and view all the answers

What basic function do both TEM and SEM share?

<p>They emit a beam of electrons towards a sample. (A)</p> Signup and view all the answers

In the calculation of magnification, what initial step is necessary?

<p>Convert all measurements to the same units. (D)</p> Signup and view all the answers

What is the primary function of the plasma membrane?

<p>To control the movement of substances in and out of the cell (A)</p> Signup and view all the answers

Which structure is not found in plant and bacterial cells?

<p>Centrioles (B)</p> Signup and view all the answers

What is the composition of prokaryotic ribosomes compared to eukaryotic ribosomes?

<p>70S for prokaryotes, 80S for eukaryotes (D)</p> Signup and view all the answers

Which of the following cells utilize cilia for movement?

<p>Epithelial cells in the trachea (B)</p> Signup and view all the answers

What role do pili serve in prokaryotic cells?

<p>Communication and plasmid transfer (A)</p> Signup and view all the answers

What is the function of a vacuole in plant cells?

<p>To store cell sap and maintain turgidity (B)</p> Signup and view all the answers

What is one distinctive feature of eukaryotic cells compared to prokaryotic cells?

<p>Presence of membrane-bound organelles (D)</p> Signup and view all the answers

Which microscope can visualize living cells in real-time?

<p>Light microscope (B)</p> Signup and view all the answers

What does the Golgi apparatus primarily do with proteins?

<p>Modifies and processes proteins (C)</p> Signup and view all the answers

What material makes up plant cell walls?

<p>Cellulose (D)</p> Signup and view all the answers

Which statement about flagella in eukaryotic cells is true?

<p>They are bundles of microtubules (B)</p> Signup and view all the answers

What is a characteristic feature of plasmids in prokaryotic cells?

<p>Replicate independently from chromosomal DNA (D)</p> Signup and view all the answers

What aspect distinguishes the transmission electron microscope (TEM) from light microscopes?

<p>It can visualize individual organelles (A)</p> Signup and view all the answers

Cytoskeleton's primary role in the cell includes which of the following?

<p>Support structure for organelles (C)</p> Signup and view all the answers

Flashcards

What is the nuclear envelope?

A double membrane that surrounds the nucleus, containing pores that allow small molecules to pass into the cytoplasm while keeping chromosomes inside.

What is the nucleolus?

A region within the nucleus where ribosomes are assembled.

What is the rough endoplasmic reticulum (RER)?

It's an extension of the nuclear envelope that facilitates protein synthesis by providing a large surface area for ribosomes.

What is the smooth endoplasmic reticulum (SER)?

This organelle plays a crucial role in lipid synthesis, including cholesterol and steroid hormones.

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What is the Golgi apparatus?

A group of fluid-filled sacs surrounded by vesicles, modifying and packaging proteins and lipids.

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What is the mitochondria?

The site of ATP production during aerobic respiration. It is self-replicating and becomes numerous in cells with high energy requirements.

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What is a lysosome?

Phospholipid rings containing digestive enzymes that engulf and destroy old organelles or foreign material.

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What is the chloroplast?

The site of photosynthesis, containing a double membrane and internal thylakoid membranes for capturing light energy.

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Cell Wall

A rigid structure that surrounds the cell, providing support and protection. It is composed of cellulose in plants, chitin in fungi, and murein in prokaryotes.

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Plasma Membrane

A phospholipid bilayer with embedded proteins that controls the movement of substances into and out of the cell.

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Centrioles

Bundles of microtubules that play a crucial role in cell division by pulling sister chromatids apart. They are also involved in the formation of cilia and flagella.

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Flagella

Tail-like structures made of microtubules that propel cells through fluids. They are found in sperm cells, which use them to swim towards the egg.

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Cilia

Finger-like projections on the cell surface, also made of microtubules. They beat rhythmically to move fluids or particles.

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Vacuole

An organelle responsible for storing cell sap, nutrients, and proteins. It helps maintain cell turgor in plants.

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Translation (Protein Production)

The process of translating mRNA into a polypeptide chain, which occurs on ribosomes.

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Cytoskeleton

A network of protein threads that supports cell organelles and maintain the cell's shape. It is crucial for cell movement.

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Prokaryotes

Organisms that lack membrane-bound organelles, such as mitochondria, Golgi apparatus, and nucleus. Their DNA is circular and found in the cytoplasm.

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Eukaryotes

Organisms that have membrane-bound organelles and a nucleus containing their linear DNA.

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Plasmids

Small, circular pieces of DNA found in prokaryotes, separate from the main chromosome. They often carry genes for antibiotic resistance.

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Pili

Hair-like structures on the surface of some bacteria, used for communication with other cells and transfer of plasmids.

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Mesosomes

A folded portion of the inner membrane in prokaryotes, believed to be involved in respiration. Its existence is debated by scientists.

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Slime Capsule

A slimy layer surrounding the cell wall of some bacteria, providing protection against immune attacks.

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Confocal Microscope

A type of light microscope that uses laser beams to scan specimens, producing clearer 3D images than conventional light microscopes.

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What is a Transmission Electron Microscope (TEM)?

A microscope that uses a beam of electrons to create images of very small objects.

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What is a Scanning Electron Microscope (SEM)?

A microscope that uses a beam of electrons to scan the surface of a sample, creating 3D images.

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What is resolution?

The ability of a microscope to distinguish between two closely spaced objects.

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What is magnification?

The amount by which an image is magnified compared to the original object.

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What are the eyepiece graticule and stage micrometer?

The eyepiece graticule is a small ruler inside the microscope's eyepiece, while the stage micrometer is a calibrated ruler placed on the microscope stage.

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What is calibrating the eyepiece graticule?

The process of aligning the eyepiece graticule and stage micrometer to determine the length of a division on the eyepiece graticule.

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What is eosin?

A stain that makes the cell's cytoplasm visible, increasing contrast and allowing visualization of organelles.

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What is the coarse adjustment knob?

The knob that moves the stage up and down, allowing you to bring the specimen into focus.

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What is a specimen used for viewing under a microscope?

A thin layer of cells placed on a microscope slide for viewing under a microscope.

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What is a coverslip?

A protective glass cover placed over the specimen, adding an extra layer of protection.

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Study Notes

Cell Structure and Function

  • Organisms are categorized into eukaryotes and prokaryotes.
  • Eukaryotic cells contain a nucleus and membrane-bound organelles.
  • Prokaryotic cells lack a nucleus and membrane-bound organelles.

Eukaryotic Organelles

  • Nucleus: Contains DNA (genetic instructions) associated with histone proteins (chromatin). Wound into chromosomes.
  • Nucleolus: Site of ribosome production.
  • Nuclear Envelope: Double membrane surrounding the nucleus; contains pores for small molecule passage.
  • Rough Endoplasmic Reticulum (RER): Extension of nuclear envelope, studded with ribosomes; facilitates protein synthesis and transport to Golgi.
  • Smooth Endoplasmic Reticulum (SER): Synthesizes lipids (cholesterol, hormones).
  • Golgi Apparatus: Modifies and packages proteins and lipids from RER and SER into vesicles. Site of lysosome synthesis.
  • Ribosomes: Synthesize proteins; can be free-floating or bound to RER.
  • Mitochondria: Site of ATP production (aerobic respiration); self-replicating, numerous in high energy cells. Contains cristae (folds) for increased surface area.
  • Lysosomes: Contain digestive enzymes; destroy old organelles or foreign material.
  • Chloroplasts: Site of photosynthesis; found only in plants/photosynthetic organisms. Double membrane; thylakoid membranes (grana, lamellae).
  • Plasma Membrane: Phospholipid bilayer with proteins (carriers) and cholesterol; controls substance movement. Maintains cell contents.
  • Centrioles: Bundles of microtubules; form spindle fibers during mitosis (cell division); important for cilia and flagella formation; absent in plant cells.
  • Cell Wall: Rigid structure; made of cellulose (plants), chitin (fungi), or murein (prokaryotes). Provides structural support to the cell.
  • Flagella: Tail-like structure made of microtubules; propel cells; found in sperm cells.
  • Cilia: Finger-like projections; made of microtubules; used for movement (e.g., in trachea, moving mucus).
  • Vacuole: Organelle that stores cell sap, nutrients, and proteins; maintains turgor pressure in plant cells; can also digest large molecules.

Protein Synthesis Pathway

  • Ribosomes translate mRNA into polypeptides or proteins.
  • Polypeptides fold in RER and are transported to the Golgi in vesicles.
  • Golgi modifies proteins, adds carbohydrate chains/sulfates/phosphates, and packages them.
  • Vesicles deliver proteins to needed locations (e.g. plasma membrane).

Cytoskeleton

  • Network of protein filaments (microfilaments and microtubules) through cytoplasm.
  • Supports organelles, maintains cell shape, and facilitates movement of organelles and chromosomes, cilia and flagella.

Prokaryotic vs. Eukaryotic Cells

  • Prokaryotes lack membrane-bound organelles; DNA is free-floating, circular chromosomes, have smaller ribosomes.
  • Prokaryotes have cell walls (murein), can have flagella (made of flagellin).
  • Prokaryotic unique structures include pili, mesosomes, plasmids, and slime capsules.

Microscopy Techniques

  • Light Microscope: Magnification up to 1500x; resolution ~0.2 µm; can observe living cells.
  • Confocal Microscope: Advanced light microscope; uses lasers to provide clearer 3D images of labelled specimens.
  • Transmission Electron Microscope (TEM): High resolution (~0.0002 µm); visualizes organelles; sample must be fixed and placed in vacuum.
  • Scanning Electron Microscope (SEM): Lower resolution (~0.002 µm); produces 3D images; sample must be fixed and placed in vacuum.

Measuring Specimen Size

  • Using eyepiece graticule and stage micrometer, calculate magnification or the size of objects.
  • Aligning graticule with micrometer allows for determining actual size.

Viewing Specimens

  • Preparing slides with water, specimen, stain, cover slip.
  • Using lowest-powered objective lens followed by increasing magnification for visualization.

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Description

Test your knowledge on the differences between eukaryotic and prokaryotic cells as well as the various organelles present within eukaryotic cells. This quiz covers key components such as the nucleus, ribosomes, and mitochondria. Dive into the fascinating world of cell biology!

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