Cell Biology Flashcards
What are microscopes used for?
To see objects that cannot be seen with the naked eye
When did purposeful magnification first appear?
Before 2500 BCE
In which century were lenses first invented?
12-13th century
Fill in the blank: Microscopes are instruments that are used to see objects that cannot be seen with the _______.
naked eye
True or False: Microscopes have been in use since before 500 CE.
True
Who are credited with creating the forerunner of the compound microscope?
Zaccharias Janssen and Hans Janssen
They experimented with multiple lenses placed in a tube.
In what year did Hooke publish his book Micrographia?
1665
This book described his observations made with a microscope.
What did Hooke observe through the microscope that led him to name them ‘cells’?
Pores/compartments in cork
His observations were made on slivers of cork.
Who is known as the ‘Father of Microbiology’?
Van Leeuwenhoek
He built numerous simple microscopes and discovered many microorganisms.
What type of microscopes did Van Leeuwenhoek build?
Simple microscopes with single lenses
He achieved magnifications up to 270X.
What did Van Leeuwenhoek study using his microscopes?
Bacteria, yeast, plants, and small organisms in pond water
His studies included a variety of small life forms.
Fill in the blank: The early compound microscope was developed in _______.
1595
This development involved the use of multiple lenses.
True or False: Hooke was the first to observe cells.
True
Hooke’s observations in cork led to the naming of cells.
Who first used specific dyes to stain specific structures in cells?
Joseph von Gerlach
He did this in 1858 and recognized the importance of staining.
What significant contribution did Oskar Heimstädt make in 1911?
Constructed the first successful fluorescence microscope
This microscope uses a high-intensity light source to excite fluorescent molecules.
What is the principle behind fluorescence microscopy?
It uses a high-intensity light source to excite a fluorescent molecule, which emits lower energy light of a longer wavelength
This emitted light produces the magnified image.
In what year was the first electron microscope invented?
1931
It was co-invented by German scientists Max Knott and Ernst Ruska.
What does an electron microscope use to illuminate a specimen?
An electron beam
This allows it to produce a magnified image.
What are the two main types of electron microscopes?
- TEM (transmission electron microscopes)
- SEM (scanning electron microscopes)
Each type has distinct imaging capabilities.
What type of images do TEM microscopes obtain?
2D images
They can magnify up to ~1,000,000X.
What type of images do SEM microscopes obtain?
3D images of surface structures
They can magnify up to ~100,000X.
Fill in the blank: The first successful fluorescence microscope was constructed by _______.
Oskar Heimstädt
Who first used specific dyes to stain specific structures in cells?
Joseph von Gerlach
He did this in 1858 and recognized the importance of staining.
What significant contribution did Oskar Heimstädt make in 1911?
Constructed the first successful fluorescence microscope
This microscope uses a high-intensity light source to excite fluorescent molecules.
What is the principle behind fluorescence microscopy?
It uses a high-intensity light source to excite a fluorescent molecule, which emits lower energy light of a longer wavelength
This emitted light produces the magnified image.
In what year was the first electron microscope invented?
1931
It was co-invented by German scientists Max Knott and Ernst Ruska.
What does an electron microscope use to illuminate a specimen?
An electron beam
This allows it to produce a magnified image.
What are the two main types of electron microscopes?
- TEM (transmission electron microscopes)
- SEM (scanning electron microscopes)
Each type has distinct imaging capabilities.
What type of images do TEM microscopes obtain?
2D images
They can magnify up to ~1,000,000X.
What type of images do SEM microscopes obtain?
3D images of surface structures
They can magnify up to ~100,000X.
Fill in the blank: The first successful fluorescence microscope was constructed by _______.
Oskar Heimstädt
What technology allows microscopes to view things smaller than the wave size of light?
Super-resolution light microscopy
This technology has been developed since 2000.
What new insights can super-resolution light microscopy provide?
Understanding of cell biology
It allows for visualization of cells at a tiny scale.
What are the capabilities of super-resolution light microscopy?
Imaging in all three dimensions and within living cells
These capabilities are developing rapidly.
What is the most commonly used microscope?
Compound light microscope
What is the upper lens of the microscope called?
Eyepiece
What holds the lenses of the microscope?
Body tube
What part of the microscope carries the objective lenses?
Revolving nosepiece
What is the lower lens of the microscope that is movable for different magnifications?
Objective lens
What holds the slide in place on the microscope?
Stage clips
What part of the microscope regulates the amount of light shining on the object?
Diaphragm
What provides light that shines through the opening and the mounted object to the eye?
Light source
What is the handle of the microscope called?
Arm
Where is the slide clipped to be observed in a microscope?
Stage
What knob moves the tube/stage with large movements to bring the object into focus?
Coarse adjustment knob
What knob moves the tube/stage with fine movements for final focus?
Fine adjustment knob
What part of the microscope ensures it stands steady?
Base
What does the original cell theory state?
The cell is the basic structural and functional unit of living organisms and all cells come from other cells.
This theory was established by Matthias Schleiden and Theodor Schwann in 1839.
Who are credited with establishing the cell theory?
Matthias Schleiden and Theodor Schwann.
They established the theory in 1839.
What did Matthias Schleiden propose about cells?
All plant tissues are composed of cells.
This foundational belief was proposed between 1838-1839.
What conclusion did Theodor Schwann make regarding cells?
All animal tissues are made of cells.
Schwann’s conclusion was integral to the development of cell theory.
What are the two foundational statements of the original cell theory?
- All living organisms consist of one or more cells
- The cell is the basic unit of life
These statements were blended by Schwann into the cell theory.
Who added the third part of the original cell theory and what was it?
Rudolf Virchow proposed that cells only arise from other cells in 1855.
This conclusion was based on his observations of mitosis.
What does the modern version of the cell theory include?
- Energy flows within cells
- Hereditary information is passed from cell to cell
- Cells are made of the same basic chemical components
These ideas reflect advancements in biological knowledge since the mid-1800s.
Fill in the blank: The cell is the _______ unit of life.
basic
This is a key concept in the original cell theory.
True or False: All living organisms consist of only one cell.
False
The original cell theory states that organisms can consist of one or more cells.
What are the two main components that all cells consist of?
Cytoplasm and a cell membrane
These components are essential for the cell’s structure and function.
What is an organelle?
A subcellular structure that has one or more specific jobs to perform in the cell
Organelles function similarly to organs in the body.
What type of cells lack a nucleus and other membrane-bound organelles?
Prokaryotic cells
Examples include bacteria.
What type of cells contain a nucleus and other membrane-bound organelles?
Eukaryotic cells
Examples include plants and animals.
Fill in the blank: Cells without a nucleus and other membrane surrounded organelles are called _______.
Prokaryotic cells
Fill in the blank: Cells with a nucleus and other membrane surrounded organelles are called _______.
Eukaryotic cells
True or False: All cells have a nucleus.
False
Prokaryotic cells do not have a nucleus.
What is the primary difference between prokaryotic and eukaryotic cells?
Presence of a nucleus and membrane-bound organelles
Prokaryotic cells lack these features.
What is the function of the cell membrane?
Regulates what enters and exits the cell
The cell membrane is a selectively permeable barrier that protects the cell’s internal environment.
What organelle contains the cell’s genetic material?
Nucleus
The nucleus houses DNA and is often referred to as the control center of the cell.
What is cytoplasm?
The gel-like substance within the cell membrane
Cytoplasm contains all organelles and is the site of many metabolic processes.
What is the primary role of mitochondria?
Energy production through cellular respiration
Mitochondria are often called the powerhouse of the cell.
What are ribosomes responsible for?
Protein synthesis
Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum.
What is the function of the endoplasmic reticulum?
Protein and lipid synthesis, and transport
The endoplasmic reticulum can be rough (with ribosomes) or smooth (without ribosomes).
What does the Golgi body do?
Modifies, sorts, and packages proteins and lipids
The Golgi apparatus plays a key role in processing and shipping cellular products.
What are vacuoles?
Storage organelles in the cell
Vacuoles can store nutrients, waste products, or other materials.
Which cells contain a cell wall?
Plant cells
The cell wall provides structural support and protection.
What is the main function of chloroplasts?
Photosynthesis
Chloroplasts contain chlorophyll and convert sunlight into chemical energy.
What is the cell membrane?
A very thin, living boundary of the cell
The cell membrane is crucial for maintaining the integrity of the cell.
What model describes the structure of the cell membrane?
Fluid Mosaic Model
The Fluid Mosaic Model explains how the cell membrane is composed of various components that move fluidly.
What are the main components of the cell membrane?
A double layer of phospholipid molecules with large proteins embedded
This arrangement allows for flexibility and functionality within the membrane.
What are the two parts of a phospholipid molecule?
Phosphate head and fatty acid tail
The phosphate head is hydrophilic, while the fatty acid tail is hydrophobic.
What does hydrophilic mean?
Attracted to water
Hydrophilic substances tend to interact well with water.
What does hydrophobic mean?
Repelled by water
Hydrophobic substances do not mix well with water.
Describe the movement of phospholipids and proteins in the cell membrane.
They constantly move around like objects floating on the surface of a lake
This movement is essential for the dynamic function of the membrane.
What is the function of the cell membrane?
Protects and encloses the cell; selectively permeable
The selective permeability allows the cell to control its internal environment.
What does selectively permeable mean?
Allows and controls the movement of substances into and out of the cell
This property is vital for maintaining homeostasis.
What are microvilli?
Tiny cell membrane projections that increase surface area
Microvilli are important for absorption and secretion processes in some animal cells.
What does hydrophilic mean?
‘Attracted’ to water
Hydrophilic substances tend to dissolve in water or interact favorably with it.
What does hydrophobic mean?
‘Repelled’ by water
Hydrophobic substances do not mix well with water and often aggregate in aqueous environments.
What is cytoplasm?
A jelly-like, colloidal solution in a cell that appears grey due to organelles and suspended substances.
The cytoplasm consists of cytosol (liquid component) and suspended proteins and organelles.
What is the liquid component of cytoplasm called?
Cytosol
The cytosol is the liquid part of the cytoplasm where various substances are suspended.
What is the solid component of cytoplasm comprised of?
Suspended proteins and organelles
These components contribute to the colloidal nature of the cytoplasm.
What structural element is found within the cytoplasm?
Cell cytoskeleton
The cytoskeleton is a network of protein fibres and microtubules that helps maintain cell shape.
What processes take place in the cytoplasm?
Metabolism
Metabolism includes all chemical processes necessary for the survival of the organism.
What are the functions of the cytoplasm?
Stores substances, gives cell shape, facilitates circulation of substances
The movement of the cytoplasm aids in the distribution of materials within the cell.