Type of cells Flashcards
Amino acids polymerise into
Proteins
Purines and pyrimidines polymerise into
polynucleotides
What are the properties of the plasma membrane?
- surrounds all the cells
- maintain homeostasis
- selectively permeable
- lipid bilayer
- communication with the external environment
- Aids in binding and adhering
What does the cell theory state?
- cells are the fundamental units of life (Schwann)
- all organisms are composed of cells (Schleiden)
- all cells come from pre-existing cells (Virchow)
Who was the first to describe cells and what type of cells were they?
Robert Hooke (cellula)
Plant cells (cork)
Who was the first to observe a living cell under the microscope and what was it?
Anton Van Leeunhoek
algae Spirogyra
what is the size of the smallest object a person can see with their naked eyes?
- 0.2 mm (200 micrometer)
- to distinguish the object, the person has to be as close to the object as the size of the object (o.2 mm) “resolution”
what are the differences between light microscope and electron microscope in term of magnification and resolution?
- Light microscope:
magnification: 1000x
resolution: 0.2 micrometer - Electron microscope:
magnification: 1,000,000x
resolution: 0.2 nanometer
Why is the cell size limited by the surface area to the volume ration?
When the volume of the cell increases the ratio of the surface to the volume decreases which means that the increase in the surface area is not proportional to the increase in volume - lesser ability to exchange with the outside environment.
How can cells overcome the surface area to the volume ratio limitation?
- Flattened cells (RBCs)
- Long and thin cells (neurons)
- Cells that has many tiny projections (epithelial)
What are the types of cells?
- Bacteria
- Archaea
- Eukarya
How are the eukaryotic cells different from the prokaryotic cells?
Prokaryotic:
* No nucleus
* No membrane-bounded compartments (organelles)
Eukaryotic:
* membrane-enclosed nucleus
* membrane-enclosed compartments (organelles)
what are the properties of the prokaryotic cell walls?
- maintain the shape of the cell
- located outside the plasma membrane
what is the prokaryotic cell wall made of?
- Peptidoglycan (Sugars + amino acids) -> bacteria
- Lipopolysaccharides (lipid + polysaccharides) -> Gram-ve bacteria “covers the peptidoglycan wall”
What is a mycoplasma?
- a bacterium that lacks a cell wall
- unaffected by some antibiotics that target the cell wall like penicillin
- Some of them are pathogenic to humans like “M. pneumoniae”
- they have the minimum amount of DNA required to sustain life.
What is a capsule in prokaryotic cells?
- a layer of slime enclosing the cell wall.
- mostly made of polysaccharides.
- protect the bacteria from white blood cells.
- help the bacteria attaching to other cells.
- Stop the bacteria from drying out.
What is the type of bacteria that can carry out photosynthesis?
cyanobacteria
What is the part of bacteria that helps some of them to swim and what is it made of?
Flagella (flagellum- singular) - looks like corkscrew.
Made of protein called flagellin.
What is a Pili?
- threadlike structure.
- helps the bacteria to stick to other bacteria or cells.
What are the shapes of bacteria?
- Spherical shape (cocci)
- Rod shaped (bacillus)
- Spiral shaped (Spirillia)
what is the equivalent of mitosis in bacteria?
Binary fission
why don’t bacteria undergo mitosis?
They don’t have true cytoskeleton.
What are inclusions in Prokaryotic cells?
- Found within the cytoplasm.
- Reserves of lipids, starch or glycogen.
what are endospores and where can they be found?
- Structures that are highly resistant to environmental stresses.
- they usually develop in vegetative cells like the bacillus and clostridium groups of bacteria.
How much larger are eukaryotic cells compared to prokaryotic cells?
10x
What are the organelles that can be found in an animal cell?
Nucleolus
Nucleus
Rough endoplasmic reticulum
Soft endoplasmic reticulum
Ribosomes
Golgi apparatus
Mitochondria
Cytoskeleton
Centrioles
Peroxisome (lysosome)
What are the organelles that can be found in the plant cell?
Animal cell’s organelles - centrioles +
Cell wall
Chloroplast
Vacuole
Where can the DNA (most of it) be found in cells?
Nucleus
what is the function of the nucleolus?
the assembly of ribosomes from RNA and specific proteins
what is the nuclear pore made of?
made of about 100 different proteins and surrounded by a complex of 8 large proteins.
what can pass through the nuclear pore in term of size?
- Small sized substances pass freely.
- medium sized substances can pass but takes longer.
- Large sized substances need a nuclear localised signal (a short sequence of amino acids) to pass.
what is the endoplasmic reticulum?
a network of interconnected membranes which branch out through the cytoplasm.
what is the difference between RER and SER?
RER is studded with ribosome
what is the function of RER?
- Segregation, transportation and modification of
newly sythesised proteins.
what are the functions of SER?
- chemical modification of small molecules taken into the cell (drugs).
- hydrolysis of glycogen.
- synthesis of lipids and steroids.
what is the difference between prokaryotic and eukaryotic ribosomes?
Prokaryotic:
* float freely in cytoplasm.
* smaller
Eukaryotic:
* can be found in cytoplasm, attach to RER and inside the mitochondria and chloroplasts.
* Larger
what is Golgi apparatus made of?
flattened membranous sacs called cisternae
what are the functions of Golgi apparatus?
- Makes further modification to proteins received from RER.
- Concentrates, packages and sorts proteins.
- Synthesizes polysaccharides for plant cell walls.
What are the different regions of the Golgi apparatus?
- Cis region (faces the RER)
- Trans region (faces the plasma membrane)
What are lysosomes and what are their functions?
- vesicles containing digestive enzymes that come from the Golgi apparatus.
- Breakdown of food and foreign materials (phagocytosis)
- digest failing cellular components (autophagy)
what is the function of the mitochondria?
- converts potential chemical energy in carbohydrates and fatty acids to ATP.
How many mitochondrial proteins that were identified in the human heart cells?
650
what is the only organelle that has its own genome?
Mitochondria
what is the benefit of the cristae?
increase the surface area for the chemical reactions.
why is cyanide poisonous to humans?
because it blocks the transfer of electrons to the last acceptor- oxygen.
where can the plastids be found?
plant cells
what is the name of the organelle that can carry out photosynthesis?
chloroplast
what are the functions of the vacuoles?
- Storage- toxins
- Structure- maintain the structure of the cell
- Reproduction- synthesis of protein for development
- Digestion- contain enzymes
why is the membrane design called the fluid mosaic model?
because of the distribution of the floating proteins on it.