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State three parts of the cell theory
All living organisms are composed of one or more cells.
The cell is the basic unit of life in all living things.
All cells arise from pre-existing cells through cell division.
How scientific theories developed?
They notice a trend or pattern in their observations and therefore use inductive reasoning.
Define resolution
Refers to the clarity or detail of an image, often measured in pixels, and also indicates the ability to distinguish between different elements in a visual display
Define magnification
The process of enlarging the appearance of an object makes it easier to see details. It is commonly used in optical instruments like microscopes and telescopes, expressed as a ratio of the size of the image to the actual size of the object.
Compare and contrast light and electron microscopes
Past 400x, light microscopes cannot have a focused image due to light distortion. However, electron microscopes have a shorter wavelength, which makes them possible. They can only produce black-and-white images, and electron microscopes kill cells.
What is fluorescent staining?
Coloured substances that bond with certain chemicals to make organelles in the cell visible.
What is freeze-fracture electron microscopy?
A steel blade fractures through the weakest point (middle of the membrane) to use ice to replicate the structures and textures on the inside of the cell.
What is cryogenic electron microscopy?
A technique used to visualize biological specimens at extremely low temperatures, preserving their native structure. It allows for high-resolution imaging of proteins and complexes in their natural state, without the need for crystallization. This method is crucial for studying the dynamics and interactions of biomolecules in a near-physiological environment.
What are the structures that are common to all cells as well as their functions?
Plasma membrane - controls entry and exit of substance
Cytoplasm - enzymes in it catalyzes reactions called the metabolism of the cell
DNA - genes (made up of DNA) contain instructions for cells
What are the structures typical of prokaryote cells?
Cell wall, Plasma membrane, Cytoplasm, 70s ribosome, nucleoid DNA, pili, flagella
What does “naked” mean when referring to prokaryotic DNA?
Refers to DNA not associated with histones or other proteins, existing in a free, unbound state within the cell.
Compare and contrast prokaryotic and eukaryotic cell structure
Prokaryotic: No nucleus; DNA in nucleoid; smaller size; no membrane-bound organelles; cell wall present in most; reproduce asexually (binary fission).
Eukaryotic: Nucleus present; DNA in chromosomes; larger size; membrane-bound organelles (e.g., mitochondria); cell wall in plants and fungi; reproduce sexually or asexually (mitosis/meiosis).
State the function of the plasma membrane
The plasma membrane serves as a protective barrier that regulates the movement of substances in and out of the cell. It maintains homeostasis by controlling the entry of nutrients and the exit of waste. Additionally, it facilitates communication between cells and their environment through receptors and signaling molecules.
State the function of cytoplasm
Cellular Metabolism: Site for metabolic processes and biochemical reactions.
Support and Structure: Provides shape and support to the cell.
Transport: Facilitates the movement of materials within the cell.
Organelles Suspension: Houses and supports organelles, allowing them to function effectively.
State the function of ribosomes
Function of Ribosomes
Ribosomes are cellular structures that synthesize proteins by translating messenger RNA (mRNA) into polypeptide chains.
In eukaryotes, ribosomes can be found free in the cytoplasm or attached to the endoplasmic reticulum (forming rough ER). They play a crucial role in protein synthesis, translating mRNA into amino acid sequences.
State the function of the nucleus
Genetic Material Storage: Houses DNA, which contains the genetic blueprint for the organism.
Regulation of Gene Expression: Controls the transcription of genes into RNA.
Cell Division: Coordinates cell division and replication processes.
State the function of mitochondria
ATP Production: They generate adenosine triphosphate (ATP) through cellular respiration
Metabolism: They play a role in metabolic processes
Regulation of Apoptosis: Mitochondria are involved in programmed cell death, helping to maintain cellular health.
Calcium Storage: They help regulate intracellular calcium levels
State the function of chloroplast
Produces energy through photosynthesis and oxygen-release processes
It absorbs light energy and converts it into chemical energy.
State the function of both endoplasmic reticulums
Rough: Studded with ribosomes, and therefore necessary for protein synthesis
Smooth: Not studded with ribosomes: for lipid synthesis.
State the function of the golgi apparatus
Where proteins received from the ER are further processed and sorted for transport to their eventual destinations: lysosomes, the plasma membrane, or secretion.
State the function of vesicles
Help transport materials that an organism needs to survive and recycle waste materials. They can also absorb and destroy toxic substances and pathogens to prevent cell damage and infection.
State the function of vacuoles
It helps in the storage of various substances, stores waste products, and prevents the entire cell from contamination. It isolates metabolic waste that might be harmful to the cell. It also helps maintain internal pressure.
State the function of lysosomes
Three main functions: A lysosome has three main functions: the breakdown/digestion of macromolecules, cell membrane repairs, and responses against foreign substances such as bacteria, viruses and other antigens.
State the function of the cytoskeleton of microtubules and microfilaments.
The function of microfilaments is to provide structure for the cell and to aid in movement. The function of microtubules is also to provide support for the cell, to assist in cell division, and to provide a route for intracellular transport.
List and define the common processes carried out by all life
M - metabolism - the sum of the reactions that occur in a living organism
R - reproduction - production of offspring, sexually or asexually
S - sensitivity - perception of stimuli and carrying out responses
H - homeostatis - maintenance of a constant internal environment
E - excretion - removal of waste products
N - nutrition - supplying required nutrients
G - growth - an increase of size/cells
Describe characteristics of parameciums that enable them to perform the function of life.
The cilia help in locomotion and sending food particles to the oral groove. Paramecium has two nuclei, macronucleus, and micronucleus that take part in the reproduction process.
Which cells between animal, fungi and plant contain plastids?
plant
Which cells between animal, fungi and plant contain a cell wall?
Fungi and Plant
Which cells between animal, fungi and plant contain vacuoles?
All
Which cells between animal, fungi and plant contain centrioles?
Animal
Which cells between animal, fungi and plant contain flagella?
All
Describe what makes red blood cells atypical
During their maturation, red blood cells discard their nucleus and mitochondria.
Discrepancy: a eukaryotic cell without a nucleus or mitochondria!
Describe what makes aseptate fungal hyphae atypical
Aseptate hyphae are not made of clearly defined individual cells, rather continuous structures with multiple nuclei.
Describe what makes skeletal muscle fibers atypical
Very large eukaryotic cell with more than one nucleus
Describe what makes phloem sieve tube elements atypical
Sieve tube elements lose their nucleus and other organelles during their development. A eukaryotic cell without organelles!
What are organelles?
Organelles are discrete structures in cells that are adapted to perform a specific function
What organelles are double membrane bound?
Nucleus, mitochondria and chloroplast
What cellular structures are not organlles and why?
Cell wall: outside the cell membrane
Cytoplasm: not specialised for a specific function
Cytoskeleton: not discrete
Why is it an advantage for the nucleus and the cytoplasm to be separate in eukaryotic cells?
Allows the mRNA to be modified in between processes (post-transcriptional modification) which allows it to have the same amount of genes, but more proteins
What are the advantages of compartimalization in the cytoplasm of cells?
Small volume allows enzymes and their substrates to be concentrated, speeding up enzyme activity
pH can be kept at the ideal level for the organelle’s function
Incompatible biochemical processes can be kept separate
What is fertilization?
Multi-step process in which a sperm and egg fuse to form a single cell called a zygote
What is cell specialization?
Allows cells to perform a function with increased efficiency
What is differentiation?
The development of specialized structures and functions in cells
What do morphogens do?
Signal molecules that direct cell fate decisions in a concentration-dependent matter
When does differentiation occur?
It occurs when different cell types express different genes
What is gene expression?
The process by which the information encoded in a gene is turned into a function
What is retinoic acid?
A morphogen that plays important roles in cell growth and differentiation
What are the properties of stem cells?
They can divide repeatedly throughout their life (ex. skin cells)
Cells created through division can be stem cells or differentiate into a specific cell type
Where do adult stem cells live?
Stem cell niches
Where are stem cell niches found?
They are found in brain, bone marrow, skeletal muscle, skin, teeth, hearth, intestines and liver
What are stem cell niches?
They are locations that receive physical and chemical signals
What is a stem cell?
A stem cell is an undifferentiated cell that can:
Divide indefinitely to create more cells
Differentiate to become a specialized cell type in a multicellular organism
Define a totipotent stem cell
can become any body cell (ex. zygote)
Define a pluripotent stem cell
can become any body cell besides the placenta (ex. inner cell mass of a blastocyst)
Define a multipotent stem cell
partially differentiated but can still become multiple types (ex. adult stem cells)
What is cell specialization and its advantage?
Cell differentiates to develop into specific shapes and sizes
It maximizes the ability of the cell to perform its specialized function
What does surface area do?
It controls the amount of exchange across the cell membrane (the more surface area, the more exchange)
What does volume do?
It dictates the amount of materials that are needed or produced in the cytoplasm
TRUE OR FALSE: As a cell becomes too large the surface area to volume ratio becomes too big
FALSE
What are some examples of how cells increase surface area?
Long cellular extension (ex. nerve cell)
Thing, flat cell shapes (ex. red blood cells)
Extension of cell membrane (ex. microvilli)
Note 
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