Podcast
Questions and Answers
Which cellular structure is indicated at a size of approximately 10 μm?
Which cellular structure is indicated at a size of approximately 10 μm?
Which of the following is the smallest structure according to the measurements provided?
Which of the following is the smallest structure according to the measurements provided?
Which microscopy technique is used to view structures smaller than 100 nm?
Which microscopy technique is used to view structures smaller than 100 nm?
At what measurement do ribosomes typically fall under?
At what measurement do ribosomes typically fall under?
Signup and view all the answers
Which of the following structures is larger than a mitochondrion but smaller than most plant and animal cells?
Which of the following structures is larger than a mitochondrion but smaller than most plant and animal cells?
Signup and view all the answers
What dimension is attributed to the smallest bacteria?
What dimension is attributed to the smallest bacteria?
Signup and view all the answers
Which structures can be visualized using super-resolution microscopy?
Which structures can be visualized using super-resolution microscopy?
Signup and view all the answers
What is the size range of most typical plant and animal cells?
What is the size range of most typical plant and animal cells?
Signup and view all the answers
What is the primary function of the cristae in the mitochondrion?
What is the primary function of the cristae in the mitochondrion?
Signup and view all the answers
Which component of the mitochondrion is responsible for storing its own genetic information?
Which component of the mitochondrion is responsible for storing its own genetic information?
Signup and view all the answers
What is the result of the process shown in the figures involving homogenization and centrifugation?
What is the result of the process shown in the figures involving homogenization and centrifugation?
Signup and view all the answers
In the diagram, where are free ribosomes located within the mitochondrion?
In the diagram, where are free ribosomes located within the mitochondrion?
Signup and view all the answers
What structures are indicated as a network in the mitochondrial diagram?
What structures are indicated as a network in the mitochondrial diagram?
Signup and view all the answers
Which type of cells consist of organisms in the domains Bacteria and Archaea?
Which type of cells consist of organisms in the domains Bacteria and Archaea?
Signup and view all the answers
Which of the following is NOT a basic feature of all cells?
Which of the following is NOT a basic feature of all cells?
Signup and view all the answers
What is the approximate size of a mitochondrion as depicted in the diagram?
What is the approximate size of a mitochondrion as depicted in the diagram?
Signup and view all the answers
What is characteristic of prokaryotic cells?
What is characteristic of prokaryotic cells?
Signup and view all the answers
Which type of cells are classified as eukaryotic?
Which type of cells are classified as eukaryotic?
Signup and view all the answers
In differential centrifugation, what does the lowest speed typically yield?
In differential centrifugation, what does the lowest speed typically yield?
Signup and view all the answers
Which feature is common to both prokaryotic and eukaryotic cells?
Which feature is common to both prokaryotic and eukaryotic cells?
Signup and view all the answers
Which component is NOT found in prokaryotic cells?
Which component is NOT found in prokaryotic cells?
Signup and view all the answers
Which structure is characteristic of eukaryotic cells?
Which structure is characteristic of eukaryotic cells?
Signup and view all the answers
What is the main function of the plasma membrane?
What is the main function of the plasma membrane?
Signup and view all the answers
What feature distinguishes eukaryotic cells from prokaryotic cells?
What feature distinguishes eukaryotic cells from prokaryotic cells?
Signup and view all the answers
Which component is NOT found in a typical bacterium?
Which component is NOT found in a typical bacterium?
Signup and view all the answers
What structure is primarily responsible for cellular communication and transport?
What structure is primarily responsible for cellular communication and transport?
Signup and view all the answers
Which part of a typical rod-shaped bacterium is involved in movement?
Which part of a typical rod-shaped bacterium is involved in movement?
Signup and view all the answers
In addition to the plasma membrane, what structure provides support to bacterial cells?
In addition to the plasma membrane, what structure provides support to bacterial cells?
Signup and view all the answers
What is the role of ribosomes in both prokaryotic and eukaryotic cells?
What is the role of ribosomes in both prokaryotic and eukaryotic cells?
Signup and view all the answers
Which structure is responsible for protein synthesis in a eukaryotic cell?
Which structure is responsible for protein synthesis in a eukaryotic cell?
Signup and view all the answers
What is the primary role of the nucleus in a eukaryotic cell?
What is the primary role of the nucleus in a eukaryotic cell?
Signup and view all the answers
Which of the following structures is part of the cytoskeleton?
Which of the following structures is part of the cytoskeleton?
Signup and view all the answers
Which organelle is involved in modifying and packaging proteins?
Which organelle is involved in modifying and packaging proteins?
Signup and view all the answers
Which structure is NOT found in a eukaryotic plant cell?
Which structure is NOT found in a eukaryotic plant cell?
Signup and view all the answers
What is the main function of mitochondria in eukaryotic cells?
What is the main function of mitochondria in eukaryotic cells?
Signup and view all the answers
What structure serves as the boundary of the cell?
What structure serves as the boundary of the cell?
Signup and view all the answers
Which part of the cell is responsible for detoxifying harmful substances?
Which part of the cell is responsible for detoxifying harmful substances?
Signup and view all the answers
What is one of the primary functions of the smooth endoplasmic reticulum (ER)?
What is one of the primary functions of the smooth endoplasmic reticulum (ER)?
Signup and view all the answers
Which structure is primarily responsible for modifying products of the endoplasmic reticulum?
Which structure is primarily responsible for modifying products of the endoplasmic reticulum?
Signup and view all the answers
What type of molecules do lysosomes primarily digest?
What type of molecules do lysosomes primarily digest?
Signup and view all the answers
Which component of the rough endoplasmic reticulum (ER) is involved in the synthesis of glycoproteins?
Which component of the rough endoplasmic reticulum (ER) is involved in the synthesis of glycoproteins?
Signup and view all the answers
Where does the Golgi apparatus receive materials for processing?
Where does the Golgi apparatus receive materials for processing?
Signup and view all the answers
What is the primary structure that makes up the Golgi apparatus?
What is the primary structure that makes up the Golgi apparatus?
Signup and view all the answers
What are hydrolytic enzymes in lysosomes primarily responsible for?
What are hydrolytic enzymes in lysosomes primarily responsible for?
Signup and view all the answers
Which of the following is NOT a function of the smooth endoplasmic reticulum (ER)?
Which of the following is NOT a function of the smooth endoplasmic reticulum (ER)?
Signup and view all the answers
Study Notes
Chapter 6: A Tour of the Cell
- All organisms are made of cells, which are the simplest collection of matter that can be alive.
- Cells are related by descent from earlier cells.
- Cells can differ, but they share common features.
Concept 6.1: Biologists use microscopes and the tools of biochemistry to study cells
- Cells are usually too small to be seen by the naked eye.
Microscopy
- Microscopes are used to visualize cells.
- In a light microscope (LM), visible light passes through a specimen and then through glass lenses.
- Lenses refract (bend) the light so that the image is magnified.
- Three key parameters of microscopy are:
- Magnification: the ratio of an object's image size to its real size.
- Resolution: the clarity of the image. It is the minimum distance of two distinguishable points.
- Contrast: visible differences in brightness between parts of the sample.
- Light microscopes can effectively magnify to about 1,000 times the size of the actual specimen.
- Techniques enhance contrast and enable cell components to be stained or labelled.
- The resolution of standard light microscopy is too low to study organelles in eukaryotic cells.
Electron Microscopy
- Two basic types of electron microscopes (EMs) study subcellular structures:
- Scanning electron microscopes (SEMs): focus a beam of electrons onto the surface of a specimen, producing 3-D images.
- Transmission electron microscopes (TEMs): focus a beam of electrons through a specimen. They are used to study the internal structure of cells.
Recent Advances in Light Microscopy
- Labeling individual cells with fluorescent markers improves detail.
- Confocal and deconvolution microscopy provide sharper 3D images of tissues and cells.
- New techniques for labelling cells improve resolution.
- Super-resolution microscopy distinguishes structures as small as 10-20nm across.
Cell Fractionation
- Cell fractionation takes cells apart and separates the major organelles from one another.
- Centrifuges fractionate cells into their component parts.
- Cell fractionation helps scientists determine the functions of organelles.
- Biochemistry and cytology help correlate cell function with structure.
Concept 6.2: Eukaryotic cells have internal membranes that compartmentalize their functions
- The basic structural and functional unit of every organism is one of two types: prokaryotic or eukaryotic.
- Only bacteria and archaea consist of prokaryotic cells.
- Protists, fungi, animals, and plants consist of eukaryotic cells.
Comparing Prokaryotic and Eukaryotic Cells
-
Basic features of all cells include: a plasma membrane, cytosol, chromosomes, and ribosomes.
-
Prokaryotic cells are characterized by:
- No nucleus
- DNA in an unbound region called the nucleoid
- No membrane-bound organelles
- Cytoplasm bound by the plasma membrane.
-
Eukaryotic cells are characterized by:
- DNA in a nucleus that is bounded by a double membrane
- Membrane-bound organelles
- Cytoplasm in the region between the plasma membrane and nucleus.
-
Eukaryotic cells are generally larger than prokaryotic cells.
The Nucleus: Information Central
- The nucleus contains most of the cell's genes and is usually the most conspicuous organelle.
- The nuclear envelope encloses the nucleus, separating it from the cytoplasm.
- The nuclear envelope is a double membrane; each membrane consists of a lipid bilayer.
- Pores regulate the entry and exit of molecules from the nucleus.
- The nuclear lamina maintains the shape of the nucleus.
- In the nucleus, DNA is organized into discrete units called chromosomes.
- Each chromosome contains one DNA molecule associated with proteins, called chromatin.
- Chromatin condenses to form discrete chromosomes as a cell divides.
- The nucleolus is the site of rRNA synthesis, located within the nucleus.
Ribosomes: Protein Factories
- Ribosomes are complexes made of ribosomal RNA and protein.
- Ribosomes carry out protein synthesis in two locations:
- In the cytosol (free ribosomes)
- On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)
Concept 6.4: The endomembrane system regulates protein traffic and performs metabolic functions in the cell
- The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and plasma membrane.
- These components are either continuous or connected via transfer by vesicles.
The Endoplasmic Reticulum: Biosynthetic Factory
- The endoplasmic reticulum accounts for more than half of the total membrane in many eukaryotic cells.
- The ER membrane is continuous with the nuclear envelope.
- Two regions of ER exist:
- Smooth ER, which lacks ribosomes.
- Rough ER, whose surface is studded with ribosomes.
Functions of Smooth ER
- Synthesizes lipids
- Metabolizes carbohydrates.
- Detoxifies drugs and poisons.
- Stores calcium ions.
Functions of Rough ER
- Has bound ribosomes, which secrete glycoproteins (proteins bonded to carbohydrates).
- Distributes transport vesicles, secretory proteins.
- Is a membrane factory for the cell.
The Golgi Apparatus: Shipping and Receiving Center
- The Golgi apparatus consists of flattened membranous sacs called cisternae.
- Modifies products of the ER
- Manufactures certain macromolecules
- Sorts and packages materials into transport vesicles.
Lysosomes: Digestive Compartments
- A lysosome is a membranous sac of hydrolytic enzymes.
- Lysosomal enzymes work best in the acidic environment inside the lysosome.
- Hydrolytic enzymes and lysosomal membranes are made by the rough ER and transferred to the Golgi for further processing.
- Lysosomes use enzymes to recycle the cell's own organelles and macromolecules in autophagy.
Vacuoles: Diverse Maintenance Compartments
- Vacuoles are large vesicles derived from the ER and Golgi.
- Vacuoles perform a variety of functions in different kinds of cells:
- Food vacuoles are formed by phagocytosis
- Contractile vacuoles, found in freshwater protists, pump out excess water.
- Central vacuoles, found in many mature plant cells, hold organic compounds and water.
Concept 6.5: Mitochondria and chloroplasts change energy from one form to another
- Mitochondria are the sites of cellular respiration and use oxygen.
- Chloroplasts are found in plants and algae and are the sites of photosynthesis.
- Peroxisomes are oxidative organelles.
Mitochondria: Chemical Energy Conversion
- Mitochondria are found in nearly all eukaryotic cells.
- They have a smooth outer membrane and an inner membrane folded into cristae.
- The inner membrane creates two compartments: intermembrane space and mitochondrial matrix.
- Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix.
- Cristae increase the surface area for enzymes synthesizing ATP.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on cellular structures and their sizes with this quiz. Questions cover topics such as microscopy techniques, ribosome measurements, and mitochondrial components. Perfect for biology students studying cellular biology or related fields.
