Cells Flashcards
What is Cell Theory?
- All organisms are composed of cells.
- Cells are the smallest living things.
- Cells only arise from pre-existing cells.
- Cells are the basic unit of life.
What is the characteristic of cell size?
Cell size is limited as most cells are relatively small due to reliance of the diffusion of substances in and out of cells
What is rate of diffusion affected by?
- The amount of surface area available
- Temperature
- Concentration gradient
- Distance
What is surface area-to-volume ratio?
- Organisms made of many small cells have an advantage over organism composed of fewer, larger cells.
- As cell size increase, volume increase much more rapidly than its surface area.
- Some cells overcome limitation by being long and narrow
Why do we use microscopes?
Not many cells are visible to the naked eye. as most cells are less than 50 micrometers.
The resolution function on microscopes allow the minimum distance between two points can be apart but still be distinguished as two separate points.
What are the types of microscopes?
Light microscopes and electron microscopes?
Which microscope do you use for atoms?
electron microscope
Which microscope do you use for amino acids & proteins?
electron microscope
Which microscope do you use for red blood cells?
electron or light microscope
Which microscope do you use for mitochondria?
electron or light microscope
Which microscope do you use for chloroplast?
electron or light miscoscope
Who proposed Cell Theory?
Schleiden and Schwann
What is the visual scale for microscopes and naked eye?
<100 nanometer = electron microscope
1nm-100nm = light microscope
>100 micrometer = Human eye
What characteristics do all cells have?
- Nucleoid or nucleus where DNA is located
- Cytoplasm that has semifluid matrix of organelles and cytosol
- Ribosomes that synthesize proteins
- Plasma membrane made up of phospholipid bilayer
What are the simplest organisms?
The two domains of prokaryotes:
Archaea and Bacteria
What do simplest organisms have and don’t have?
1.They lack a membrane bound nucleus.
2.DNA present in nucleotide.
3.Cell Wall is outside of plasma membrane.
4.Have ribosomes.
There are no organelles common to all prokaryotes.
True
What are bacterial micro-compartments?
Cellular compartments bounded by a semipermeable protein shell. (40 - 400nm)
What are the functions of BMCs?
Isolate specific metabolic processes and storage.
What is peptidoglycan?
A form of polysaccharide.
What is most bacterial cell walls composed of?
Peptidoglycan
What are fungi cell walls composed of?
Chitin
What are plant walls composed of?
Cellulose
What is the function of a cell wall?
- Protect the cell
- Maintain shape
- Prevent excessive uptake or loss of water
What do arcane cell walls lack?
Peptidoglycan, however make it up in diversity of components like protein and saturated hydrocarbons + glycerol.
What is flagella?
Present in prokaryotic cells that are used for locomotion that rotates to propel cell forward.
What are eukaryotic cells?
Eukaryotic cells possess a membrane-bound nucleus and are more complex than prokaryotic. They also posses a cytoskeleton.
What is eukaryotic noted by?
Compartmentalization = has many compartments because of membrane bound organelles and endromembrane system.
What is the endomembrane system?
A series of membranes throughout cytoplasm that divides cells into compartments where different cellular functions occur.
What is the main difference between eukaryotes and prokaryotes?
One of the fundamental distinctions between eukaryotes and prokaryotes is that eukaryotes have an endomembrane system.
What is a endoplasmic reticulum and its types?
An organelle that helps with protein synthesis. (produce protein for rest of cell to function)
Rough endoplasmic reticulum (RER) and Smooth endoplasmic reticulum (SER)
What is the function of Smooth endoplasmic reticulum (SER)?
It has a few bound ribosomes that synthesize proteins, store calcium and detoxify.
Where are calcium ions mostly stored?
In the smooth endoplasmic reticulum to keep rest of cell amount lower.
Cells that secrete more more antibodies have more of which type of ER?
Rough Endoplasmic Reticulum
What is the Golgi apparatus?
Flattened stacks of interconnected membranes that form the Golgi bodies.
What is the function of the Golgi apparatus?
Main function is packing and distribution of molecules synthesized at one location and then transported to be used at another location within the cell or even outside.
What is the cis face of a Golgi apparatus?
The cis face receives molecules from ER.
What is the trans face of a Golgi apparatus?
The trans face releases prepared or processed molecules in the form of vesicles to the outside, other parts of cell.
What are vesicles?
Vesicles transport molecules to destination.
(Transport, Fusing, Forming, Secretory Vesicles)
What are lysosomes?
Membrane bound digestive vesicles that are released from Golgi apparatus that contain enzymes that catalyst breakdown of macromolecules.
What is the function of lysosomes?
- It fuses with targets (vesicles, membrane, plasma membrane) to imitate breakdown of macromolecules.
- Recycles old organelles
- Digest cells and foreign matter that cell has engulfed by phagocytosis (break down
What are vacuoles?
Membrane bound structures, typically found in plants. Its function varies depending on cell type.
What are microbodies?
A variety of enzymes bearing membrane enclosed vesicles peroxisomes.
What are peroxisomes?
Contains enzymes involved in oxidation of fatty acids that produce hydrogen peroxide as a by product that converts _ to a less toxic form.
What are ribosomes?
Cell’s protein synthesis machinery (where protein synthesis occurs) Ribosomes are found in all cell types in all three domains
What are the types of ribosomes?
- Ribosomal RNA (rRNA)
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
What does protein synthesis require?
- Ribosomal RNA (rRNA)
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
Where are ribosomes?
Ribosomes may be free in cytoplasm (cytosol) or associated with internal membranes (ER), or mitochondria matrix.
What is a nucleus?
A nucleus is the repository of genetic information.
Most eukaryotic cells posses a single nucleus.
What is a nucleolus?
Region where ribosomal RNA synthesis takes place. It also performs as a nuclear envelope.
What does the nucleolus have?
- Two phospholipid bilayers
- Nuclear pores that control movement in and out.
What is chromatin?
Chromosomes + protein
What are the differences and similarities of animal and plant cells?
- Both have largely the same structure.
- Have plasma membrane.
- Contain most of the same organelles.
Plant cells have extra components usually not present in other eukaryotic cells.
- Cell wall outside of plasma membrane.
- Chloroplasts and specialized vacuoles internally.
What is the mitochondria?
Mitochondria has its own DNA and is found in all types of eukaryotic cells.
What is cristae?
Inner membrane shaped into folds
What are chloroplasts?
Organelles present in cells of plants and some other eukaryotes that are surrounded by two membranes.
Contain chlorophyll for photosynthesis
What are thylakoids?
Membranous sacs within the inner membrane
What are stacks of thylakoids
Grana
Chloroplasts plasts have their own DNA: T or F?
True
What is the endosymbiosis theory?
Theory proposes some present day eukaryotic organelles evolved by a symbiosis between two free-living cells. A prokaryote cell engulfed by another cell and became apart of it.
Mitochondria and chloroplasts have similarities to prokaryotic cells.
What are the three types of fibers in cells?
Cytoskeleton molecules: Microfilaments (actin filaments), Microtubules, Intermediate Filaments
What are actin filaments?
Two protein chains loosely twined together, this fiber creates movements such as: contraction, crawling, pinching.
What are microtubules?
- Largest of cytoskeletal elements
- Facilitate movement of cells and materials within cell
- Dimers of a- and B-tubulin subunits
What are intermediate filaments?
- Between size of microfilaments and microtubules
- Very stable, not usually broken down
What are centrosomes?
Centrosomes are the microtubule organizing center. Can nucleate the assembly of microtubules. Region surrounding centrioles in almost all animal cells.
Plant and fungi cells lack centiroles; T or F?
True
Animal cells and most protists have centrioles; T or F?
True
Describe cell movement.
- Movement of actin filaments, microtubules, or both help cells to move.
- Some cells crawl using actin microfilaments.
Describe eukaryotic cell walls.
Eukaryotic cell walls are present in plants, fungi and some protists which are distinct from prokaryotic cell walls chemically and structurally.
What is extracellular matrix (ECM)?
ECM is used to secrete an elaborate mixture of glycoproteins into space around them, used in replacement as animal cells lack cell wall.
Forms a protective layer over cell surface
Explain cell to cell interactions.
- Surface proteins give cells identity.
- Cells make contact with each other.
- Read each other and react
What are cell connections?
Adhesive Junctions, Septate (Tight Junctions), Communicating Junctions
What are Adhesive Junctions?
Mechanically attaches cytoskeletons of neighboring cells or cells to the ECM
Septate (Tight Junctions)
Connect the plasma membranes of adjacent cells in a sheet – no leakage
Communicating Junctions
Chemical or electrical signal passes directly from one cell to a adjacent one (gap junction, plasmodesmata).
What are plasmodesmata?
Specialized openings in plant cell walls. Cytoplasm of adjoining cells are connected
Function is similar to gap junctions in animal cell
