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Questions and Answers
What is the basic unit of structure and function in all living things?
What is the basic unit of structure and function in all living things?
The cell
What is the approximate number of cells that make up the human body?
What is the approximate number of cells that make up the human body?
100 trillion
Human cells are typically visible to the naked eye.
Human cells are typically visible to the naked eye.
False
What is the range of diameters for human cells?
What is the range of diameters for human cells?
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What is the term used to describe the study of the structure and functions of cells?
What is the term used to describe the study of the structure and functions of cells?
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Which of the following is NOT a function of the cell membrane?
Which of the following is NOT a function of the cell membrane?
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The cell membrane is composed of a ______ layer of phospholipid molecules.
The cell membrane is composed of a ______ layer of phospholipid molecules.
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Membrane proteins are only hydrophilic, meaning they have a strong affinity for water.
Membrane proteins are only hydrophilic, meaning they have a strong affinity for water.
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What is the term for the fluid that surrounds the organelles within a cell?
What is the term for the fluid that surrounds the organelles within a cell?
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What type of organelle is responsible for protein synthesis?
What type of organelle is responsible for protein synthesis?
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Proteins released from the endoplasmic reticulum (ER) are fully functional and ready to perform their duties in the cell.
Proteins released from the endoplasmic reticulum (ER) are fully functional and ready to perform their duties in the cell.
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What is the primary function of the Golgi apparatus in a cell?
What is the primary function of the Golgi apparatus in a cell?
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Describe the structure of lysosomes.
Describe the structure of lysosomes.
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The process by which worn cell parts are digested by autophagy is called ______.
The process by which worn cell parts are digested by autophagy is called ______.
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Peroxisomes are involved in the detoxification of harmful or toxic substances within the cell.
Peroxisomes are involved in the detoxification of harmful or toxic substances within the cell.
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What is the nickname given to mitochondria, and why?
What is the nickname given to mitochondria, and why?
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What is the primary function of the nucleus?
What is the primary function of the nucleus?
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What component of the nucleus is responsible for the synthesis of ribosomes?
What component of the nucleus is responsible for the synthesis of ribosomes?
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The cytoskeleton is a network of fibers that extend throughout the ______.
The cytoskeleton is a network of fibers that extend throughout the ______.
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List the three main components of the cytoskeleton.
List the three main components of the cytoskeleton.
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Microtubules are involved in separating chromosome copies during cell division.
Microtubules are involved in separating chromosome copies during cell division.
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What is the main function of centrioles?
What is the main function of centrioles?
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Which of the following structures are hair-like cellular extensions that help move substances through passageways?
Which of the following structures are hair-like cellular extensions that help move substances through passageways?
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Flagella are typically present in large numbers on a single cell.
Flagella are typically present in large numbers on a single cell.
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What is the main function of microvilli?
What is the main function of microvilli?
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Describe the function of tight junctions in cells.
Describe the function of tight junctions in cells.
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What type of cell junction acts as an anchoring point between cells, preventing tissues from fraying?
What type of cell junction acts as an anchoring point between cells, preventing tissues from fraying?
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What type of cell junction allows chemical substances to pass directly between cells?
What type of cell junction allows chemical substances to pass directly between cells?
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Which of the following is NOT a type of passive transport across the cell membrane?
Which of the following is NOT a type of passive transport across the cell membrane?
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Passive transport requires energy from ATP.
Passive transport requires energy from ATP.
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What is the movement of substances from a region of higher concentration to a region of lower concentration called?
What is the movement of substances from a region of higher concentration to a region of lower concentration called?
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What is the process of water movement across a selectively permeable membrane, from a region of higher water concentration to a region of lower water concentration, called?
What is the process of water movement across a selectively permeable membrane, from a region of higher water concentration to a region of lower water concentration, called?
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In a hypotonic solution, a cell will lose water and shrink.
In a hypotonic solution, a cell will lose water and shrink.
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Describe the condition of a cell placed in a hypertonic solution.
Describe the condition of a cell placed in a hypertonic solution.
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Active transport is a process that moves substances from a lower concentration to a higher concentration using a carrier protein and energy.
Active transport is a process that moves substances from a lower concentration to a higher concentration using a carrier protein and energy.
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Which of the following is NOT a type of endocytosis?
Which of the following is NOT a type of endocytosis?
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Phagocytosis involves the engulfment of large particles, like bacteria or cellular debris, by the cell.
Phagocytosis involves the engulfment of large particles, like bacteria or cellular debris, by the cell.
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Describe the process of pinocytosis.
Describe the process of pinocytosis.
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Exocytosis is a process by which substances are released from the cell.
Exocytosis is a process by which substances are released from the cell.
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In facilitated diffusion, ______ proteins speed up the movement of molecules across the plasma membrane.
In facilitated diffusion, ______ proteins speed up the movement of molecules across the plasma membrane.
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Which type of transport protein provides corridors that allow specific molecules or ions to cross the membrane?
Which type of transport protein provides corridors that allow specific molecules or ions to cross the membrane?
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Carrier proteins undergo a shape change to translocate the solute-binding site across the membrane.
Carrier proteins undergo a shape change to translocate the solute-binding site across the membrane.
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What distinguishes active transport from passive transport?
What distinguishes active transport from passive transport?
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Active transport is essential for maintaining specific concentrations of ions and molecules within the cell.
Active transport is essential for maintaining specific concentrations of ions and molecules within the cell.
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In exocytosis, transport vesicles migrate to the [blank], fuse with it, and release their contents.
In exocytosis, transport vesicles migrate to the [blank], fuse with it, and release their contents.
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Endocytosis involves the cell taking in large molecules by forming new vesicles from the plasma membrane.
Endocytosis involves the cell taking in large molecules by forming new vesicles from the plasma membrane.
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Study Notes
General Zoology 1 - Lecture (1)
- The lecture is about cell anatomy and physiology.
- The cell is the fundamental unit of structure and function in living organisms.
- Cells vary in shape, size, and arrangement, but they all have similar components with specific functions.
- The human body is composed of approximately 100 trillion cells.
- All human cells are microscopic in size, shape, and function.
- Cell diameter ranges from 7.5 micrometers (RBC) to 150 mm (ovum).
- Cytology is the study of cell structure and functions.
Introduction
- A cell is the fundamental unit of any organism.
- Cells are important for producing energy for metabolism (all chemical reactions within a cell).
- Cells can mutate (change genetically) due to accidental changes in their genetic material (DNA).
- Cytology is the study of cell structure and functions.
Cellular Organelles
- Diagrams and labels of cell organelles are included in the lecture slides. The specific components described for each organelle follow.
Cell Structure – Plasma Membrane
- The plasma membrane is a thin, dynamic membrane that encloses the cell and controls what enters and leaves the cell.
- The Fluid Mosaic Model describes the plasma membrane as a double layer (bilayer) of phospholipid molecules with embedded protein molecules.
- The surfaces of the membrane are hydrophilic due to polar phosphate heads.
- The internal portion of the membrane is hydrophobic due to non-polar fatty acid tails.
- Membrane proteins have both hydrophobic and hydrophilic regions.
Cellular Structure - Cytoplasm, Endoplasmic Reticulum , Ribosomes
- Cytoplasm is a gel-like matrix of water, enzymes, nutrients, wastes, and gases that contains cell structures (organelles).
- The fluid around the organelles is called cytosol.
- Most of the cell's metabolic reactions occur in the cytoplasm.
- Endoplasmic reticulum (ER) is a network of interconnected parallel membranes that is continuous with the nuclear membrane. There are two types of ER—rough (RER) and smooth (SER).
- Rough ER is studded with ribosomes, responsible for protein synthesis and intracellular transport.
- Smooth ER lacks ribosomes and functions in lipid and cholesterol synthesis, and calcium storage.
- Every cell contains thousands of ribosomes, many attached to the RER.
- Ribosomes are non-membranous structures made of two subunits, a large subunit, and a small subunit with rRNA.
- Ribosomes synthesize proteins. Proteins released from the ER need further processing in the Golgi complex.
Cell Structure - Golgi Apparatus
- Golgi apparatus consists of flattened membranous sacs (cisternae) arranged in stacks ("stacks of pancakes").
- Golgi is associated with vesicles (membrane-bound sacs containing proteins).
- Golgi functions in the modification, packaging, and transport of proteins.
- Golgi encloses digestive enzymes into membranes to form lysosomes.
Cell Structure - Lysosomes
- Lysosomes are spherical membranous sacs containing digestive enzymes.
- Lysosomes function as "suicide sacs" destroying cellular components, no longer used by the cell.
- Autolysis is the process by which worn cell parts are digested by autophagy.
Cell Structure - Peroxisomes
- Peroxisomes are membranous sacs containing oxidase enzymes.
- Peroxisomes function in the detoxification of harmful or toxic substances (e.g., alcohol, formaldehyde, oxygen free radicals).
- Hydrogen peroxide (H2O2) is converted to water.
Cell Structure - Mitochondria
- Mitochondria are kidney-shaped organelles whose inner membrane is folded into shelf-like partitions called cristae.
- Mitochondria are the "powerhouse" of the cell, responsible for cellular respiration, releasing energy from glucose.
Cell Structure - Nucleus
- The nucleus is the central core, control center, or "brain" of the cell.
- It's the largest organelle, filled with nucleoplasm.
- The nuclear membrane (or nuclear envelope) is a double membrane separating the nucleus from the cytoplasm.
- Pores in the nuclear membrane allow the passage of materials like mRNA.
- Nucleoli are spherical bodies within the nucleus, composed of RNA and proteins, and involved in ribosome synthesis.
Cell Structure - Cytoskeleton
- The cytoskeleton is a network of fibers extending throughout the cytoplasm, providing support and aiding in cell movement.
- The components include microfilaments, intermediate filaments, and microtubules, including centrosomes and centrioles.
Cell Membrane Surface Modifications
- Cilia/cilium: short, hair-like extensions used for movement and substance transport.
- Flagella: tail-like projections aiding in cell locomotion.
- Microvilli: small, finger-like extensions increasing cell surface area for absorption.
Membrane Junctions
- Tight junctions prevent leakage between cells, creating impermeable barriers.
- Desmosomes provide anchoring junctions, preventing tissue fraying.
- Gap junctions facilitate communication between cells.
Transport Across the Plasma Membrane
- Transport across the plasma membrane is categorized as passive or active transport.
- Passive transport mechanisms include simple diffusion, osmosis, and facilitated diffusion, requiring no energy.
- Active transport mechanisms, such as endocytosis and exocytosis, require energy for movement against concentration gradients.
Transport: Endocytosis
- Endocytosis is a form of active transport that brings substances (large particles or molecules) into the cell.
- Phagocytosis is a type of endocytosis where large particles enter the cell.
- Pinocytosis is a type of endocytosis where fluids are taken into the cell.
Transport: Exocytosis
- Exocytosis is a form of active transport that releases materials from a cell.
- During exocytosis, substances are packaged into a vesicle, which migrates to the plasma membrane. The vesicle fuses with the membrane and releases its contents into the extracellular environment.
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Description
This lecture covers the essential topics of cell anatomy and physiology, focusing on the fundamental unit of life. Explore the diversity of cell shapes, sizes, and their respective functions, as well as the integral role of cells in metabolism and energy production. A deep dive into cytology and cellular organelles will provide insight into the microscopic world of human cells.
