p.6
Cell Fractionation Techniques
What does electron microscopy of a cell fraction indicate?
It can show the presence of a large number of mitochondria.
p.9
Eukaryotic Cell Structure
What defines the boundary of a eukaryotic cell?
The cell surface membrane.
p.5
Cell Fractionation Techniques
What is cell fractionation?
A technique to separate major organelles from each other to study their structures and functions.
p.6
Cell Fractionation Techniques
What is the primary purpose of cell fractionation?
To isolate specific cell components in bulk to identify the functions of organelles.
p.6
Cell Fractionation Techniques
What conclusion can biologists draw from the presence of mitochondria in a cell fraction?
That mitochondria are the sites of cellular respiration.
What methods can enhance contrast in microscopy?
Staining or chemical-labeling of cell components.
What is the role of membranes in organelles?
They allow compartmentalization, maintaining optimum conditions for specific functions.
p.9
Eukaryotic Cell Structure
What types of protein filaments are found in the cytoskeleton?
Microtubules, microfilaments, and intermediate filaments.
p.5
Cell Fractionation Techniques
What are the two types of centrifugation techniques?
Differential centrifugation and density gradient centrifugation.
How do new daughter cells arise?
From cell division of a parental cell.
p.26
Prokaryotic Cell Characteristics
What is a key characteristic of the cytoplasm in bacteria?
It lacks membrane-bound organelles found in eukaryotes.
p.8
Prokaryotic Cell Characteristics
What is a key structural difference between prokaryotes and eukaryotes?
Prokaryotes lack a nucleus, while eukaryotes have a defined nucleus.
p.26
Organelles and Their Functions
What types of storage granules can be found in the cytoplasm of bacteria?
Glycogen and lipid droplets.
p.8
Eukaryotic Cell Structure
What type of organisms are eukaryotes?
Plants, animals, fungi, and protists.
Who were the key figures in the development of the Cell Theory?
Matthias Schleiden and Theodor Schwann.
p.9
Eukaryotic Cell Structure
What is the function of the nucleus in a eukaryotic cell?
It contains hereditary material, DNA, that directs cellular activities.
p.26
Ribosomes and Protein Synthesis
What is the function of polyribosomes in bacteria?
They allow the simultaneous synthesis of many polypeptide chains from a single mRNA.
p.19
Organelles and Their Functions
What role does the Golgi apparatus (GA) play in plant cells after nuclear division?
It is involved in the formation of the new cell wall.
p.19
Organelles and Their Functions
What are lysosomes?
Small spherical vesicles (0.2-0.5 μm) formed by vesicles from the Golgi apparatus found in animal cells.
p.8
Eukaryotic Cell Structure
Do eukaryotic cells have a complex cytoskeleton?
Yes, eukaryotic cells have a complex cytoskeleton.
p.23
Prokaryotic Cell Characteristics
What are the three most common shapes of bacteria?
Spheres (cocci), rods (bacilli), and spirals.
p.22
Organelles and Their Functions
What role do centrioles play in animal cells?
They are involved in nuclear division.
What tools do biologists use to study cells?
Microscopes and other tools of biochemistry.
p.24
Prokaryotic Cell Characteristics
How are bacteria classified based on their cell wall structure?
Into Gram positive or Gram negative bacteria.
What is the endomembrane system?
A system of intracellular membranes in eukaryotic cells that compartmentalizes organelles.
p.20
Lysosomes and Their Functions
What triggers autolysis in a cell?
Lysosomes releasing their contents within the cell, usually after damage or death.
p.7
Prokaryotic Cell Characteristics
Where is most of the DNA located in a prokaryotic cell?
In a region called the nucleoid, which is not membrane-bound.
p.14
Eukaryotic Cell Structure
What is the size range of chloroplasts?
Diameter: 0.5-2 μm; Length: 5-10 μm.
p.7
Organelles and Their Functions
What types of organelles do eukaryotic cells have?
Double-membrane (e.g., nucleus, chloroplast, mitochondria), single-membrane (e.g., endoplasmic reticulum, Golgi apparatus, lysosomes), and non-membrane bound (e.g., ribosomes, centrioles).
p.21
Ribosomes and Protein Synthesis
Are free and bound ribosomes structurally different?
No, free and bound ribosomes are structurally identical and can alternate between roles.
What is contrast in microscopy?
The visible differences between various parts of the sample.
What is magnification in microscopy?
The ratio of an object's image size to its real size.
p.8
Prokaryotic Cell Characteristics
Do prokaryotes have membrane-bound organelles?
No, prokaryotes do not have membrane-bound organelles.
p.11
Eukaryotic Cell Structure
What are nuclear pores?
Channels on the nuclear envelope for the movement of molecules between the nucleus and cytoplasm.
What are some characteristics that define a living organism?
1) Display order. 2) Exhibit homeostasis. 3) Respond to stimuli. 4) Display heredity. 5) Acquire and utilize energy. 6) Reproduce. 7) Evolve and adapt.
p.25
Prokaryotic Cell Characteristics
What do bacterial cell surface membranes consist of?
A phospholipid bilayer and proteins.
p.20
Lysosomes and Their Functions
What is the role of lysosomes in white blood cells like macrophages?
They engulf bacteria for defense.
p.15
Evolution of Eukaryotic Cells
What type of cell did an early ancestor of eukaryotic cells engulf?
An oxygen-using non-photosynthetic prokaryotic cell.
p.15
Evolution of Eukaryotic Cells
What is an endosymbiont?
A cell living within another cell.
p.2
Eukaryotic Cell Structure
What adaptations do larger eukaryotic cells have for transport?
Organelles and structural adaptations.
p.12
Eukaryotic Cell Structure
What does the nucleus store that is essential for genetic continuity?
Hereditary material (DNA).
What are the two main types of microscopes mentioned?
Light microscopes and electron microscopes.
p.8
Prokaryotic Cell Characteristics
How do prokaryotic and eukaryotic cells differ in size?
Prokaryotic cells are generally smaller than eukaryotic cells.
p.5
Cell Fractionation Techniques
What is homogenisation?
The process of breaking open cells to release cellular contents.
p.9
Eukaryotic Cell Structure
What is the cytoskeleton?
A framework of protein filaments that gives eukaryotic cells their shape and serves other functions.
p.24
Prokaryotic Cell Characteristics
What are the two main components of the peptidoglycan structure?
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
p.11
Eukaryotic Cell Structure
What are histones?
Proteins around which DNA is coiled to form chromatin.
p.25
Prokaryotic Cell Characteristics
What is a mesosome in bacteria?
An in-folding of the membrane for attachment of the bacterial chromosome during binary fission.
p.24
Prokaryotic Cell Characteristics
What is the glycocalyx and its forms?
A coating on the outer surface of the cell wall that can be a slime layer or a structured capsule.
p.24
Prokaryotic Cell Characteristics
What advantages does the glycocalyx provide to bacteria?
Helps adhere to surfaces, protects from viral attack and toxic substances, conserves water, and aids mobility.
p.15
Evolution of Eukaryotic Cells
What do the large arrows in the endosymbiotic theory diagram represent?
Change over evolutionary time.
How does the nucleus control cell activities?
By regulating gene expression and protein synthesis.
p.17
Organelles and Their Functions
What happens to proteins synthesized in the rER?
They are either inserted into membranes, secreted, or packaged into lysosomes.
p.21
Organelles and Their Functions
What is the structure of centrioles?
Centrioles exist as a pair of rod-like structures with a diameter of 200 nm and a length of 500 nm, positioned at right angles to each other.
p.26
Prokaryotic Cell Characteristics
What is the appearance of the cytoplasm in an electron micrograph?
It often appears more darkly stained outside of the nucleoid region.
What are the three important parameters in microscopy?
Magnification, resolution, and contrast.
Why are most organelles within eukaryotic cells difficult to resolve using standard light microscopy?
Because they are too small.
p.5
Cell Fractionation Techniques
How can cells be broken apart during homogenisation?
By cutting, grinding, chemicals, enzymes, sound waves, or forcing through small spaces at high pressure.
p.5
Cell Fractionation Techniques
What is centrifugation?
The separation and isolation of organelles of different sizes using centrifugal force.
What is the purpose of a transmission electron microscope (TEM)?
To study the internal structure of cells.
p.25
Prokaryotic Cell Characteristics
How do the proportions of proteins and lipids in bacterial membranes compare to eukaryotic membranes?
Bacterial membranes usually have a higher proportion of proteins.
p.22
Organelles and Their Functions
Do fungi and plant cells have centrioles?
No, they do not have centrioles in their centrosomes.
What are some components of the endomembrane system?
Nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, and cell surface membrane.
p.25
Prokaryotic Cell Characteristics
What are plasmids?
Small, double-stranded, circular, extra-chromosomal DNA found throughout the cytoplasm.
p.15
Evolution of Eukaryotic Cells
What do the small arrows inside the cells in the endosymbiotic theory diagram indicate?
The process of the endosymbiont becoming an organelle.
p.21
Ribosomes and Protein Synthesis
What distinguishes proteins made on free ribosomes from those made on rough ER?
Proteins made on free ribosomes generally function within the cell, while those made on rough ER are destined for membranes, organelles, or export from the cell.
What is the endomembrane system?
A complex internal membrane system in eukaryotes involved in the synthesis, transport, and modification of proteins and lipids.
p.14
Organelles and Their Functions
What types of reactions occur in the chloroplast during photosynthesis?
Light-dependent reactions occur on the thylakoid membrane, while light-independent reactions (Calvin cycle) occur in the stroma.
How does a light microscope work?
It passes visible light through the specimen and glass lenses to magnify the image.
p.9
Organelles and Their Functions
What are organelles?
Discrete subcellular structures with specific functions.
p.11
Eukaryotic Cell Structure
What is the shape and size of the nucleus?
Spherical or ovoid shape with a diameter of 10-20 μm.
p.11
Eukaryotic Cell Structure
What encloses the nucleus?
A double membrane called the nuclear envelope.
What is the resolution limit of a light microscope?
About 0.2 μm, regardless of magnification.
p.5
Cell Fractionation Techniques
What does differential centrifugation involve?
A series of centrifugation at successively higher speeds to spin down organelles of increasingly smaller sizes.
p.11
Eukaryotic Cell Structure
What fills the nucleus?
A semi-fluid matrix called nucleoplasm.
p.20
Lysosomes and Their Functions
What do lysosomes fuse with to digest materials?
Vesicles formed by endocytosis, such as food vacuoles.
p.15
Evolution of Eukaryotic Cells
What does the endosymbiotic theory explain?
The evolution of eukaryotic cells.
p.2
Prokaryotic Cell Characteristics
What are the two types of cells based on size?
Prokaryotic cells (0.5-10 μm) and eukaryotic cells (10-100 μm).
p.7
Prokaryotic Cell Characteristics
What does the term 'eukaryotic' mean?
'True nucleus' (from Greek 'eu' meaning true and 'karyon' meaning kernel).
p.1
Organelles and Their Functions
What are the functions of organelles in eukaryotic cells?
Organelles perform various functions essential for the cell's survival and operation, such as energy production, protein synthesis, and waste processing.
p.7
Organelles and Their Functions
What is a major difference between prokaryotic and eukaryotic cells regarding organelles?
Prokaryotes lack membrane-bound organelles, while eukaryotes have many.
p.18
Organelles and Their Functions
What is the distinct structural polarity of the Golgi apparatus?
The membranes of the cisternae on opposite sides differ in molecular composition.
p.7
Prokaryotic Cell Characteristics
Do prokaryotic cells have internal membranes?
Most do not, but some have infoldings of the cell surface membrane associated with respiration or photosynthesis.
p.14
Organelles and Their Functions
What types of genetic material are found in the stroma of chloroplasts?
Circular DNA and 70S ribosomes.
p.17
Organelles and Their Functions
What is one of the roles of calcium ions stored in the sER?
They are required for signal transduction during cell signaling or muscle contraction.
p.26
Ribosomes and Protein Synthesis
What are clusters of ribosomes in bacteria called?
Polyribosomes or polysomes.
p.5
Cell Fractionation Techniques
What are the two phases of cell fractionation?
Homogenisation and centrifugation.
What is the effective magnification limit of light microscopes?
About 1,000 times the actual size of the specimen.
What is resolution in microscopy?
A measure of the clarity of the image, defined as the minimum distance that allows two points to be distinguished as separate.
What is the purpose of a scanning electron microscope (SEM)?
To study the detailed surface of a specimen.
p.23
Prokaryotic Cell Characteristics
What are bacilli?
Rod-like prokaryotes that are mostly solitary but can form chains.
p.7
Prokaryotic Cell Characteristics
What are the two main types of cells?
Prokaryotic and eukaryotic.
p.1
Prokaryotic Cell Characteristics
What is the structure of a typical bacterial cell?
Small and unicellular, with a peptidoglycan cell wall, circular DNA, 70S ribosomes, and lack of membrane-bound organelles.
p.11
Eukaryotic Cell Structure
What are the two forms of chromatin in a non-dividing cell?
Heterochromatin (more condensed) and euchromatin (less condensed).
What is the significance of microscopy in cell theory development?
Microscopy allowed scientists to observe cells, leading to the formulation and expansion of the Cell Theory.
What membranes are not included in the endomembrane system?
Mitochondrial or chloroplast envelopes.
p.21
Ribosomes and Protein Synthesis
What is the primary function of ribosomes?
They are the site of protein synthesis, where amino acids are joined to form polypeptide chains via peptide bonds.
p.18
Organelles and Their Functions
What is glycosylation in the context of the Golgi apparatus?
It is the addition of short chains of sugar molecules to proteins for proper function and routing.
p.16
Eukaryotic Cell Structure
What are the two types of endoplasmic reticulum?
Rough endoplasmic reticulum (rER) and smooth endoplasmic reticulum (sER).
p.16
Eukaryotic Cell Structure
Are the membranes of the rough and smooth ER connected?
Yes, the membranes are connected and their internal spaces are continuous.
p.13
Organelles and Their Functions
What is the primary function of mitochondria?
They are the site of cellular respiration, producing ATP.
p.6
Cell Fractionation Techniques
What can biochemical tests on a cell fraction reveal?
They can show the presence of enzymes for cellular respiration.
p.26
Ribosomes and Protein Synthesis
What type of ribosomes are found in the cytoplasm of bacteria?
70S ribosomes, consisting of a small subunit (30S) and a large subunit (50S).
p.9
Eukaryotic Cell Structure
What is cytosol?
The fluid portion of the cytoplasm that contains ions and organic compounds.
What type of microscope is required to see organelles in detail?
An electron microscope (EM).
p.19
Organelles and Their Functions
What do lysosomes contain?
Hydrolytic enzymes (e.g., lipases, proteases, nucleases) surrounded by a single membrane.
p.19
Organelles and Their Functions
What is the pH level of the contents inside lysosomes?
The contents are acidic, and the enzymes have a low optimum pH.
p.19
Organelles and Their Functions
What is the primary function of lysosomes in animal cells?
They serve as a digestive component and organelle-recycling facility.
p.22
Organelles and Their Functions
What do centrioles function as in the cell?
Microtubule organizing centers (MTOC) for spindle fiber assembly.
p.23
Prokaryotic Cell Characteristics
What are the two types of spiral prokaryotes?
Spirilla and spirochetes.
p.2
Prokaryotic Cell Characteristics
Why can prokaryotic cells efficiently transport materials?
Their small size allows for quick diffusion of ions and organic molecules.
p.7
Eukaryotic Cell Structure
Where is most of the DNA located in a eukaryotic cell?
In the nucleus, enclosed by a nuclear envelope.
p.15
Evolution of Eukaryotic Cells
What may have happened after the formation of the mitochondrion?
The eukaryotic cell may have engulfed a photosynthetic prokaryote, leading to chloroplasts.
p.21
Ribosomes and Protein Synthesis
What are polyribosomes?
Clusters of ribosomes that allow simultaneous synthesis of many polypeptide chains from a single mRNA.
p.17
Ribosomes and Protein Synthesis
What role do ribosomes play in the rER?
They synthesize proteins attached to the rER.
p.18
Organelles and Their Functions
What happens to modified proteins in the Golgi apparatus?
They are sorted and packaged into secretory vesicles that bud off from the trans face.
p.16
Eukaryotic Cell Structure
What distinguishes rough endoplasmic reticulum (rER) from smooth endoplasmic reticulum (sER)?
rER has ribosomes attached, giving it a studded appearance, while sER does not.
p.16
Eukaryotic Cell Structure
How is the rER connected to the nuclear envelope?
It is continuous with the outer membrane of the nuclear envelope.
p.19
Organelles and Their Functions
How do Golgi vesicles contribute to the formation of the new cell wall in plant cells?
They move between the two daughter nuclei, forming the new cell membrane and contributing to the new cell wall.
What are the three principles of cell theory?
1) All living organisms are composed of one or more cells. 2) The cell is the smallest and most basic unit of life. 3) Cells grow from pre-existing cells.
p.23
Prokaryotic Cell Characteristics
What is the typical size range of bacteria?
0.1-10 μm in length, with an average diameter of 1 μm.
p.23
Prokaryotic Cell Characteristics
What are cocci?
Spherical prokaryotes that can be found singly, in pairs, in chains, or in clusters.
What did Robert Hooke contribute to cell biology?
He discovered cells in 1665 using one of the first microscopes.
p.24
Prokaryotic Cell Characteristics
What allows the passage of water, ions, and small molecules in the bacterial cell wall?
Tiny pores in the cell wall.
p.20
Lysosomes and Their Functions
What happens to the products of digestion in lysosomes?
They may be absorbed into the cytoplasm or released from the cell.
p.12
Organelles and Their Functions
What is the primary function of the nucleolus?
Site of transcription of rRNA and assembly of ribosomal subunits.
p.12
Eukaryotic Cell Structure
Is the nucleolus a membrane-bound organelle?
No, it is not enclosed by a membrane.
p.20
Ribosomes and Protein Synthesis
What are ribosomes composed of?
Proteins and ribosomal RNA (rRNA).
p.17
Organelles and Their Functions
What is the primary function of the rough endoplasmic reticulum (rER)?
Protein synthesis and transport.
p.20
Ribosomes and Protein Synthesis
Where can ribosomes be found in a cell?
Attached to the rough endoplasmic reticulum (rER) or free in the cytosol.
p.18
Organelles and Their Functions
What are the main functions of the Golgi apparatus?
To chemically modify, sort, and package proteins or lipids made in the rER and sER.
p.21
Organelles and Their Functions
What are microtubules made of?
Microtubules are long hollow tubes made up of tubulin proteins.
p.18
Organelles and Their Functions
What can happen to vesicles from the Golgi apparatus?
They can fuse with each other to form lysosomes.
p.13
Organelles and Their Functions
What is the function of the inner membrane's cristae?
They project into the matrix and increase surface area for biochemical reactions.
p.13
Organelles and Their Functions
What does the semi-fluid matrix of the mitochondrion contain?
Circular DNA and 70S ribosomes.
p.23
Prokaryotic Cell Characteristics
What are the main characteristics of prokaryotes?
They are simple, unicellular microorganisms that lack nuclei or membrane-bound organelles.
p.11
Eukaryotic Cell Structure
What is the outer membrane of the nucleus continuous with?
The endoplasmic reticulum.
What is the Cell Theory?
The Cell Theory states that cells are the smallest unit of life, all cells come from pre-existing cells, and living organisms are composed of cells.
p.8
Eukaryotic Cell Structure
What is the genetic material structure in eukaryotes?
Linear DNA organized into chromosomes.
p.24
Prokaryotic Cell Characteristics
How does the bacterial cell wall prevent cell lysis?
It prevents bacteria from bursting when they absorb water.
p.12
Organelles and Their Functions
What does the nucleolus contain that is essential for ribosome production?
Genes coding for ribosomal ribonucleic acid (rRNA).
p.15
Evolution of Eukaryotic Cells
What did the engulfed prokaryotic cell eventually become?
A mitochondrion within the host eukaryotic cell.
Why is the cell surface membrane considered part of the endomembrane system?
Because it interacts with other organelles of the endomembrane system.
p.7
Prokaryotic Cell Characteristics
What are plasmids?
Smaller circular DNA molecules found throughout the cytoplasm of prokaryotic cells.
p.18
Organelles and Their Functions
What is the structure of the Golgi apparatus (GA)?
It consists of a stack of flattened membrane-bound sacs known as cisternae, which are not physically connected.
p.14
Organelles and Their Functions
What is the function of the thylakoid membrane in chloroplasts?
It forms a network of thylakoids, which are involved in photosynthesis.
p.18
Organelles and Their Functions
What occurs at the cis face of the Golgi apparatus?
Transport vesicles from the rough endoplasmic reticulum (rER) fuse, bringing proteins to the GA.
What is the role of transport vesicles in the rER?
They package proteins and move them to other parts of the cell, like the Golgi apparatus.
p.5
Cell Fractionation Techniques
What is density gradient centrifugation?
Involves setting up a sucrose gradient where organelles migrate to form a band at the position where their density equals that of the sucrose solution.
p.19
Organelles and Their Functions
How do digestive processes in plant cells differ from those in animal cells?
In plant cells, digestive processes involve the vacuole, while in animal cells, they involve lysosomes.
p.11
Eukaryotic Cell Structure
What happens to chromatin during nuclear division?
It condenses into chromosomes.
p.25
Prokaryotic Cell Characteristics
What type of DNA do all bacteria have?
A single, double-stranded, circular DNA called bacterial chromosome.
p.25
Prokaryotic Cell Characteristics
Where is the bacterial chromosome located?
In a region of the cytoplasm known as the nucleoid, which is not membrane-bound.
p.12
Ribosomes and Protein Synthesis
What role does DNA within the nucleus play in protein synthesis?
It serves as templates for protein synthesis.
p.20
Ribosomes and Protein Synthesis
What are the sedimentation coefficients of eukaryotic ribosomes?
80S, consisting of a small subunit (40S) and a large subunit (60S).
p.18
Organelles and Their Functions
What is the shape and function of the trans face of the Golgi apparatus?
The trans face is concave and is where budding of secretory vesicles occurs.
p.17
Organelles and Their Functions
What is the function of the smooth endoplasmic reticulum (sER)?
Lipid synthesis, detoxification of drugs, and storage of calcium ions.
p.13
Eukaryotic Cell Structure
What type of membrane structure does a mitochondrion have?
It is bound by a double membrane.
p.13
Organelles and Their Functions
What is the significance of the 70S ribosomes in mitochondria?
They allow for protein synthesis within the mitochondrion.
p.25
Prokaryotic Cell Characteristics
What type of genes do plasmids contain?
Genes that are not essential for survival but beneficial in stressful conditions, such as antibiotic resistance.
p.14
Eukaryotic Cell Structure
What surrounds each chloroplast?
A double membrane called the chloroplast envelope.
p.21
Organelles and Their Functions
Where are centrioles located in animal cells?
Next to the nucleus in a region called the centrosome.
p.17
Organelles and Their Functions
Why is the rER abundant in liver cells?
Because it synthesizes and modifies proteins that will be secreted from the cell.
p.13
Eukaryotic Cell Structure
What is the typical shape of a mitochondrion?
Cylindrical or rod-shaped.
p.13
Evolution of Eukaryotic Cells
What theory explains the presence of circular DNA and 70S ribosomes in mitochondria?
The endosymbiotic theory.
p.18
Organelles and Their Functions
How are proteins modified as they move through the Golgi apparatus?
Proteins are transported from one cisterna to the next via vesicles and modified through a series of reactions.
p.13
Eukaryotic Cell Structure
What are the dimensions of a mitochondrion?
Width ranges from 0.5-1.5μm and length ranges from 3-10μm.
p.21
Organelles and Their Functions
What is the arrangement of microtubules in centrioles?
Centrioles have 9 triplets of microtubules arranged in a ring, with each triplet attached by fibrils.
p.13
Organelles and Their Functions
How many mitochondria can a metabolically-active cell have?
More than 1000 mitochondria.
p.14
Organelles and Their Functions
What substances are found in the stroma of chloroplasts?
Starch grains and oil droplets.
p.16
Eukaryotic Cell Structure
What is the structure of the endoplasmic reticulum (ER)?
A series of interconnected membranous sacs and tubules called cisternae.
