Chapter 7, Inside the Cell Flashcards
What does the cell theory state?
All organisms consists of cell,
All cells derived from pre-existing cells,
What are the two families of cells and which type of organisms belong to these two familes.
Prokaryotic Cells, Domains of Bacteria and Archea
Eukaryotic Cells, Kingdoms of Animalia, Plantae, Fungi and Protists
What determines the rate of materal exchange of a cell?
The rate of material exchange in and out of a cell is a function of its surface area. Higher surfance area = more nutrients can be obtained (higher rate), but higher volume = more nutrients needed.
What are the 4 basic features that all cells posses?
Cells posses: Plasma membrane (What seperates whats is the in and out of the cell), Cytosol (fluid inside the cell), DNA (genetic information), Ribosome (protein manufacturer)
What determines the minimum and maximum size of a cell?
Minimun size is baed on the size needed to fit the necessary parts for reproduction and surival. The Maximum size is set by the amount of nutrients required and the amount of waste produced.
What is the ratio for the rate of material exchange of a cell?
Surface Area / Volume
As the surface area / volume increase, the ratio decreases. As a result small cells have a greater SA/V ratio than large cells of the same shape.
What are Eukaryotic cells characterized by having what?
They contain DNA in a nucleus that is bounded by a membranous nuclear envelope, Cytoplasm in the region between the plasma membrane and nucleus.
They also have a large number of distinct membrane-bound organelles.
What do Prokaryotic Cells contain?
They contain a single,circular chromosome located in the nucleoid
Most prokaryotes have cell walls, what are they made out of?
In most bacteria, the cell wall is made of peptidoglycan
What is the importance of membrane-bound organelles in eukaryotes?
- Increases the internal surface area for…
- Internalized compartments separate incompatible reactions.
- Internalized compartments increase the efficiency of chemical reactions
- Molecules can be actively transported around the cell
- Storage of molecules
What is in the nucleoid?
Composed of DNA and proteins,
Contains genes which code for polypeptides,
Tightly coiled to fit inside the cell (super coiled)
What do some bacteria have that others do not have?
Some bacteria may have membrane-bound organelles, which are in the cytoplasm that is bounded by the plasma memrbane.
What might prokaryotic cell have?
They alsom may contain small,circular DNA molecules called plasmids
What is the difference between cytoplasm, cytosol and nucleoplasm
Cytoplasm is the inside of any part inside of the cell between the plasma membrane and the nuclear envelope.
Cytosol is the fluid (liquid) part of the cytoplasm, which is gthe inside of the cell between the plasma membrane and the nuclear envelope.
Nucleoplasm is the fluid (liquid) part found inside of the nucleous that is bounded by the nuclear envelope.
What is one advantage of bigger cells for unicellular eukaryotes?
When we have a bigger cell in comparison to a smaller cell, the bigger cell can eat the smaller cell.
What are the three structures that are found in plant cells but not in animal cells?
Rigid cell wall. Chloroplasts. Central vacuole
List at least four organelles that are found in eukaryotes but not in prokaryotes?
Nucleus, Endoplasmic reticulum, Mitocondria, Golgi apparatus, peroxisome, plasma membrane, ribosome, some componets for cytoskeleton.
List two structures that are found in animal cells but not in plant cells?
Centrosomes and Lysosomes
What does the nuclear envelope have on the outside?
They have nuclear pore complexes that allow molecules into and out of the nucleus
What is the Nucleus?
The nucleus is large, highly organized and contains the DNA (a.k.a “information central’)
Surrounded by a double-membrane nuclear envelope (two phospholipids bilayer)
Has a distinct region called the nucleolus, where: Ribosomal RNA is synthesized. (R RNA) and Ribosome subunits are assembled.
If the nucleus needed proteins, how would it get it?
The proteins needed in the nucleus are made in the cytoplasm and imported into the nucleus. These proteins could be proteins for copying DNA or synthesizingRNA, or Proteins for ribosomes.
What is made inside of the nucleus?
Ribosomes and RUNA are synthesized in the nucleus and exported to the cytoplasm. Ribosomal RNA binds proteins to form ribosomes
Messenger RNA (mRNA) carries information to synthesize proteins.
What can also enter the nucleus?
Nucleotides for building DNA and RNA also can enter.
What are ribosomes and what are they made out of?
Ribosomes are the protein factorties. They are particed made of ribosomal RNA and proteins.
How are ribosomes formed?
They are formed by two subunits. A large and a small subunit
Where does protein synthesis happen?
They occur in two locations: In the cytosol (free ribosomes)
On the outside of the endoplasmic reticulum or nuclear envelope (bound ribsomes)
What is the system of interconnected organelles called?
The system of interconnected membranous organelles is called the endomembrane system. The organelles inside the cells communicate with each other
What does the endomembrane system do?
The organelles manufacture,distribute and break down cell products.
What structure/organells are part of the endomemrbane system?
Nuclear envelope, Endoplasmic reticulum, Golgi apparatus, Lysomes, (transport vesicles), Vacuoles, Plasma membrane.
What is the endoplasmic reticulum
It is the Biosynthetic Factory, located on the outer membrane of the nuclear envelope and is physically continuous with the endoplasmic reticulum.
What are the parts ot an endoplasmic reticulum.
The endoplasmic reticulum is a networrk of interconnected tubules and fallted sacs. The interior space is called the Lumen
What is the purpose of the smooth endoplasmic reticulum
Mainly inolved in the synthesis of lipids (i.e., phospholipids and steroids)
Detoxification (enzymes are embedded in smooth ER to convert toxic organic, lipid-soluble chemicals to safer water-soluble products so that they can be easily excreted from the body.)
Stores calcium ions in muscle cells. (ions found in sarcoplasmic reticulum, tpye of smooth ER)
Portions of the smooth ER bud off to produce vesicles that are free to move in the cytosol.
What is the purpose of the rough endoplasmic reticulum
Has bounded ribosomes, which are involved in the production of proteins
What is the Golgi Apparatus
Is the receiving and shipping centre. Not physiscally attached to ER, but transported from the ER via vesicles.
What are the functions of the Golgi apparatus
To further modify proteins and lipids produced in the ER (attaches tag)
To sort proteins and lipids as they move to their final destinations
To syntehsize the cell’s carbohydrates
What is the golgi appartus consist of?
They consists of a series of flattened membrane sacs called cisternae that surrounded by small vesicles.
These vesicles transprot proteins from the ER to the Golgi appartus and between the Golgi appartus and the plasma membrane or other organelles.
What does the enzymes within the Golgi apparatus chemically modify?
The enzymes modify proteins and lipids and they pass through
What are Lysosomes
Are specialied vesicles derived from the Golgi apparatus that break down damaged or unneeded macromolecules (can degrade proteins, nucleic acids, lipids and complex carbohydrates), Digestion centre.
Macromolecules needing to be degraded are packaged by the golgi apparatus into vesciles that fuse with lysosomes.
What are the steps in proteins synthesis and sorting in the endomembrane system
Proteins produced in the endoplasmic reticulum by the ribosomes in the endoplasmic reticulum
First the protein is produced by the ribosomes, which is attached inside the endoplasmic reticulum
Then put in a transport vesicle. Which arrives into the cis side of the golgi apparatus (receiving side), it will be modifed in the Golgi Apparatus,
Then exported from the trans side into another transport vesicle to be transported to its final destination. Which can be secreted out of the cell for example.
What is the detailed function of bound ribosomes?
Polypeptides are manufactured in the RER if an ER signal sequence is present in the first 20 amino acids residues
When the ER signal is recognized, a signal recognition particle (SRP) binds to ribosome, causing translation to pause. The SRP then binds to a receptor on the RER
Translation counties and the growing polypeptide is fed into the ER lumen (interior space).
List three possible destinations for the proteins made by bound ribosomes
To other organelles of the endomembrane system
To prelysomal compartment
Directly to the plasma membrane or outside of the cell for secretion from plasma membrane.
What is the process of exo cytosis?
A vesicle that has budded off from the endomembrane system can fuse with the plasma membrane and deliver its contents into the extracellular space.
What is the process of endocytosis?
Process is revered of exocytosis. In endocytosis, material from the outside of the cell is brought into a vesicle that can then fuse with other organelles
What are the two types of endocytosis
Receptor-mediated endocytosis and Phagocytosis
What is Receptor-mediated endocytosis
Particles bind to receptors on the plasma membrane
Plasma membrane pinches off to form vesicle
What is Phagocytosis
Plasma membrane engulfs a smaller cell or food particle. Forms a phagosome
What is Autophagy
Autophagy is when lysosomes digest large structures and organelles in the cytoplasm. Portion of the cytoplasm, including damaged organelles, are enclosed to form an autophagosome.
Fuses with a lysosome for digestion.
Describe the threee pathways of recyling via the lysosomes.
- Lysosome can further breakdown molecules, from an endocytic vesicle, creating an endosome and ccan be used in another way.
- A food that is engulfed through phygocytosis, forms a phagosome , which merges into the lysosome for digestion.
- Autophagy is when an organelle is damaged, is enclosed forming an autophagosome that is delivered and digested by the lysosome.
The lysosome has three ways to break down unused or new nutrients and materials to then release back int othe cytosol for its next use.
What is the peroxisome
Single membrane organelle, which originats as vesicles from ER,
Not part of the endomembrane system.,
Contains a crystalline core, which contains enzymes responsible for conducting reducing-oxidation (redox) reactions.
What are the some of the reactions in peroxisomes
Participates in the oxidation of ethanol from alcoholic beverages.
Some enzymes are involved in chemical breakdown (metabolism) of long fatty acids.
Many reactions conducted in peroxisome generated reactive oxygen species (ROS), such as hydrogen peroxide (H2O2)
What can Reactive Oxygen Species (ROS) do? How can you prevent the effects of the ROS
They can quickly react with any biological molecule, damaging and compromising their function.
To avoid these damages, a series of antioxidant enzymes (e.g. superoxide dismutase and catalse) evolved to protect the cell from harmful ROS molecules.
What other ways can ROS be created and what happens to the cell when there is an excess of ROS
ROS can be generated by exposure to radiation, tobacco and other drugs. If the presence of ROS is higher than the capacity of the cell to contain its reactivity, the cell eneters a state of oxidative stress that can lead to sevre damage.
What enzymes are in peroxisomes that protect cells from ROS.
Catalase, superoxide dismutase, and peroxidase.
What do plants, fungi and certain other group lack? What is the replacement?
They lack lysosomes, instead they contain a more prominent organelle called a vacuole
Where were Vacuoles’ derived from?
Vacuoles’ components derive from ER and Golgi and perform different function, including transport and storage of molecules
What are Contractile vacuoles?
Found in many freshwater protists, pump excess water out of the cells.
What are central vacuoles?
Found in many mature plant cells, they hold organic compounds and water.
What are some examlpes of compounds stored in vacuoles of plants (including the plant structure)
In seeds, cells may contain large vacuoles with proteins
In flower petals or fruits, cells may contain vacuoles that are filled with colourful pigments
Vacuoles may be packed with noxious compounds that protect leaves and stems from being eaten by predators. (Nicotine, THC, CBD, other psychotropic compounds found in large quantities in plants to provide protection against predation)
What is the endosymbiosis theory and list at least three peieces of evidence that support this theory.
Endosymbiosis theory states that mitrocondria and chloroplast cells come from large cells, ancestral Eukaryote, that engulfs them. Instead of absorbing them, they formed a symboitic relationship, where the mitocondria and chlorplast provides energy while the larger ancestral eukaryote provided protection. The mitrocondria (proto bacgteria) and chloroplast (cyanobacteria) were previous aeorbic hetrerotrophic prokaryotes.
What is the cytoskeleton?
Is a network of fibres, that extending throughout the cytoplasm that provide structural support and enables the movement of substances within the cell
What makes up the fibres of cytoskeleton?
Proteins subunits
What are the 3 cytoskeletal elements part of (polymer,monomer, etc)
They are all polymers of protein subunits.
What does the cytoskelton do?
They make up the cellular skelton, fucntiong like a dynamic scaffolding contained within a cell’s cytoplasm
What part of the cytoskeleton does all Eukaryotic cells have?
They have at least two cytoskeletal elements: microtubules and microfilaments.
What do animal cells also have in the cytoskeleton
They have intermediate filaments
What is the structure,subunits and functions of Actin filaments (microfilaments)
Actin filaments are two coiled structure with Actin subunits.
They maintain cell shape by resisting tension(Pull)
Move cells via muslce contraction or cell crawling
Divide animals cell into two (mitosis)
What is the structure,subunits and functions of intermediate filaments
The fibres wound into thicker cables, with Keratine, lamin and other subunits. Main functions are to maintain cell structure by resisting tension (pull)
anchor nucleus and some other organelles
What is the structure,subunits and functions of Microtubules
A hollow tube that is a polymer. Its made from alpha and beta tubulin dimers. Functions are to maintain cell shape by resisting compressing (push), move cells via flagella or cilla,
Move chromosomes during cell division, assist formation of cell plate during plant cell division, provides tracks for intracellular transport.
What is a dimer?
Two similar moluecules forming a bond.
Where do microtubules originate from?
From the microtubules organism centers (MTOC).
What end of microtubes grows outwards?
The plus ends grows outwards, radiationg though the cell, which helps maintain a cell’s shape and allows it to withstand compression.
What is the microtubule organizing centre called in animals?
It is called a centrosome, and contains two bundles of microtubules called centrioles that are 90 degrees from each other (perpendicular)
How big are microfiliments?
They are 7nm in length
How are microfilaments grouped up?
They are grouped together into long bundles or dense networks
What kind of network do they form and what is it called?
The 3D network is called the cortext just inside the plasma membrane to help support the cell’s shape. Bundles of microfilaments make up the core of microvilli of intestinal cells.
How do microtubules and microfilaments constantly change?
They can become longer by the addition (polymerization) of subunits to the ends, and shrink by the loss of subunits (depolymerization)
Which side is the faster growing end, which side is the slower growing end of the polymers the cytoskeleton?
The plus end is the faster growing end,
The minus end is the slower growing end,
What are the 3 general types of cellular movement?
Cell movement itself
Change in cell shape
Movement of molecules/organelles within the cell
How is cell crawling done, and what cells are capable of moving via cell crawling
Actin polmerization drives amoeboid movement,
Microfilaments are asembled and extended at one end of the cell and exisitng microfiliaments are pulled together at the other end.
Neurons, Immune endothelial and epithelial cells.
What cytoskeleton component is in cellular motility?
Microfillaments
What is the main motor protein responsible for cellular motility?
The main motor protein is myosin
How do muscles contract?
Microfilaments that function in cellular motility interact with Myosin
What is cytoplasmic streaming in plants?
Cytoplasmic streaming is when the cytoplasma moves, the molecules and organelles move around the cell to better distirbute the nutrinet around the entire cell
Movement from myosine nad microfilaments creating a circular movement around the central vacuole of a plant cell, allowing the molecules to spread out evenly in the cell.
What are the 3 main motor proteins and which cytoskeleton componet do they use as tracks?
Myosin, Kinesin and Dynein
Myosin = Microfilaments
Kinesin and Dynein = Microtubules,
Kinesin is (+) end and Dynein (-)
Which motor protein helps move transport vesicles?
Mytosin can use microfilaments as tracks to move cellular cargo, like transport vesicles around the cell
Which end does the myosin move towards, of a microfilament?
Move towards the plus end
How is the energy created for the movement of the motor proteins?
The energy comes from hydrolysis of ATP
What controls the beating of cilla and flagella?
Microtubules
One example of a cell that has cilla
Epithelia cells
One example of a cell or organims that possess flagella
Male Gametes (Sperm)
What is the organization of both cilla and flagella?
Each cilla or flagella consits of a completx “9 + 2” arrangement of microtubules called axoneme, which is convered by the plasma membrane
Where is the axoneme attached?
Attachced to the cell at the basal body, which is identical in strucuture with a centriole, the basal body aids in growth of the axoneme
How do cillum (cillia) or flagellum (flagella) move?
The Dynenin “walks” up the microtubules towards the minus ends, when the dynenin arms on only one side of the axoneme move, the cillum/flagellum bends which results in a swimming motion.
