Angrini 1-6 & Chedrese 1-1.2 Flashcards
1
Q
What is biology?
A
The study of life
2
Q
Macromolecules
A
Molecules with a large number of atoms (proteins, nucleus acids); A large molecule composed of many repeated subunits termed monomers. Organic macromolecules interact to create a cell.
Complex organic molecules that are the basis of life.
3
Q
Polymers
A
Materials made of long, repeating chains of molecules. Many monomers bonded together to create carbohydrates, proteins, nucleic acids
4
Q
All living organisms…
A
1 use energy and metabolized 2 respond to environment 3 homeostasis 4 growth 5 reproduce 6 evolve
5
Q
Organic molecules
A
Carbon-based molecules
6
Q
Autotroph and heterotroph
A
Autotrophs synthesize their own organic molecules using energy from the sun.
Heterotrophs ingest organic molecules from autotroph’s or other heterotrophs
7
Q
Homeostasis
A
State of steady internal physical and chemical conditions maintained by living systems; imbalance can lead to disease or death
8
Q
Cytology & it’s two rules
A
The study of the cell.
1 all organisms are made up of cells
2 all cells share common structures, but there are differences between cells of different types
9
Q
Who first discovered cells using a microscope? Who proposed cell theory? And who completed cell theory?
A
1665 Robert Hooke examine cork cells under a microscope.
1838 Schleiden and Schwann propose the cell theory: cell is the basic functional and structural unit of all living things and all living organisms carry out essential process of life.
1855 Rudolph Virchow propose that cells come from other cells, completing cell theory
10
Q
What are the three points of cell theory (or how do we define living things)?
A
1 all living organisms are composed of one or more cells.
2 the cell is the basic unit of all living organisms.
3 cells are not created, but arise from Isaac‘s existing cells by division.
11
Q
Who disproved spontaneous generation and how?
A
In 1859 Louis Pasteur discovered vaccinations through the process of pasteurization, disproving spontaneous generation.
12
Q
What evidence is there that proves cell theory is correct?
A
If cells are broken open, the property of life is lost. They are unable to grow, reproduce, or respond to outside stimuli.
13
Q
What is the range size for most cells?
A
1 to 100 µm
Note: cells are easier to replace without disruption of function because they are small
14
Q
What are two main cell metabolic demands and what is the limiting factor in metabolism?
A
1 fuel from complex nutrients
2 elimination of waste
Therefore transport of molecules is the limiting factor in cell metabolism
15
Q
What is simple and facilitated diffusion?
A
Simple diffusion is the main way to move molecules into a cell. It is very rapid over a short distance and slower over a long distance.
Facilitated diffusion uses mechanisms like selective pumps
16
Q
What is the relationship between cells surface area and volume?
A
The increase the volume of a cell has greater substance exchange needs, but the surface area is not large enough to comply with this need. Increase in diameter means an increase in volume therefore cells cannot increase in size beyond certain limits due to speed of diffusion and the surface area to volume ratios.
17
Q
What are microvilli?
A
Extensions of the cell membrane that drastically increase surface area without greatly increasing volume
18
Q
Who invented the microscope?
A
Zacharias Jansen
19
Q
Who was Anton van Leeuwennhoek and why was he the father of microbiology?
A
He established the discipline of microbiology, built a series of single lens microscope‘s, and discovered diverse protists which he called animalcules.
20
Q
What are the two branches and three types of microscopes?
A
Optical
Electron: transmission and scanning
21
Q
What is magnification?
A
The ratio between the size of an image produced by a microscope and its actual size
22
Q
What is resolution?
A
Ability to observe two adjacent objects as distinct from one another; measure of the clarity of the image or ability to differentiate between two dots
dependent upon the wavelength of light used
23
Q
What is contrast?
A
How different one structure looks from another (enhanced by dyes)
24
Q
What is a light or a compound microscope?
A
Trick question it’s the same thing as an optical microscope
25
Why might a scientist use an electron microscope over an optical microscope?
They have different revolving powers, electron microscope‘s are more powerful
26
What are the six types of optical or light microscopes?
Light micrograph, phase contrast microscope, fluorescence microscope, dark field microscope, and Bright Field microscope, and Normarski or confocal laser scanning microscope.
27
Function of light micrograph?
Uses properties of visible light and chromophores (pigments naturally occurring in cells)
28
Phase contrast microscope function and one major advantage?
Optical microscope enhances contrast between intracellular structures have a slight different thickness using a refractive index.
Note: A major advantage of this microscope is that living cells can be examined in their natural state
29
Fluorescence microscope function?
| & What is GFP?
High contrast conventional light microscope with additional features (chemical dyes, protein fluorescence)
GFP (green fluorescent protein) are used to see cytoskeleton in the skin cell. Was isolated by Osamu Shimomura from jellyfish & Douglas Prasher developed it to be inserted into genes of other cells and expressed.
30
What are dark-field and bright-field microscopes?
Bright field microscopy gives a magnified image of the dark or coloured image of specimen with a colourless background
Dark field microscopy light illuminates the specimen at an angle and light scattered by the specimen reaches the viewing lens. This gives a bright image of the cell against a dark background
31
Normaski/ confocal laser scanning microscopes
Special lenses enhance difference in density giving a cell a 3-D appearance . Can focal laser scanning uses lasers and florescence to create this 3-D image
32
What are the two types of electron microscopes?
SEM (scanning electron microscope) and TEM (transmission electron microscope)
33
What is the function of TEM?
A beam of electrons is focussed on the thin section of a specimen in a vacuum. Electrons that pass through for the image and structures that scatter electrons appear dark. Transmission electron microscopy is used primarily to examine structures within cells. Various staining and fixing the kids are used to highlight structures of interest.
34
What is the function of SEM?
A beam of electrons is scanned across a whole cell or organism and the electrons excited on the specimen surface or converted to 3-D appearing images. Objects are coded with an electron dense material often letter gold allowing the surface to be visible.
35
What is a synchrotron and how does it work?
A large machine that accelerates electrons to almost the speed of light. As electrons are deflected through magnetic fields they create extremely bright light. This display structural and chemical properties of materials at the molecular level.
36
What are the five steps of the scientific method?
```
1 Observations
2 make hypothesis
3 Carry out experiments
4 collect and analyze data
5 support or reject the hypotheses
```
37
What are carbohydrates and their functions?
Carbohydrates are composed of carbon, hydrogen, and oxygen atoms linked together to form simple sugars or monosaccharides.
Their source of energy, cellulose provide shape to plant cells, components in antibiotics and coenzymes, and part of nucleic acids/DNA/RNA
38
What are complex carbohydrates?
Two simple sugars combined are disaccharides. Three is a trisaccharide. Larger than that is a polysaccharide (starch and glycogen).
39
What is dehydration synthesis and hydrolysis?
Dehydration synthesis is when the components of a water molecule are removed as sub units join into a larger molecule.
Hydrolysis is when the components of a water molecule are added as molecules are split into smaller subunits
40
What are proteins and their functions? What are amino acids?
Proteins contain carbon, hydrogen, oxygen, and nitrogen.
Amino acids are organic compounds that combine to form proteins; bound together by peptide bonds.
Proteins assist cells with support, metabolism, chemical reactions as enzymes, transport, defence as antibodies, motion, and structure in the cell membrane.
41
What are lipids and their functions?
Lipids contain carbon, hydrogen, and oxygen. They are hydrophobic so insoluble in water. Lipids are ampiphatic meaning hydrophilic polar ends and hydrophobic non polar ends.
Fatty acids, triglycerides, phospholipids, steroids
42
What are nucleic acid’s and their functions?
They are a polymer of nucleotides. There are two kinds DNA and RNA.
Nucleotides are made up of:
1. Nitrogenous bases in...
DNA (Adenine, thymine, guanine and cytosine)
RNA (uracil, adenine, guanine, and cytosine)
2. Five carbon sugar
Ribose in RNA & deoxyribose in DNA
3. A phosphate group
43
What is the major difference between prokaryotes and eukaryotes?
Eukaryotes have a true nucleus while prokaryotes have a nucleoid
44
Carl Linnaeus discovered taxonomy, what is it?
The science of defining a name in groups of biological organisms on the basis of shared characteristics.
Species, genus, family, order, class, phylum, kingdom, domain, and life
45
What are the three groups of life?
Bacteria, Archea, and Eukarya
Note: prokaryotes include bacteria and archea
46
Bacteria and archaea are the smallest cells. What are three common characteristics?
Simple cell structure
no membrane-bound sub cellular compartments
no organelles
47
What are the outer components of prokaryotic cells and their functions?
The plasma membrane is surrounded by a rigid external cell wall that is coated with a polysaccharide for a protective slime layer
48
What are the functions of pili and flagella in prokaryotic cells?
Pilli are hair like extensions on the outer capsule of prokaryotic cells and flagella resemble tails. Their function is movement and adherence to services.
49
How do bacteria reproduce?
Binary fission
50
What are Cyanobacteria?
Bacteria with the photosynthetic capabilities, the only prokaryotes capable of producing oxygen. Also the only prokaryotes with internal membranes: thylakoid membrane around chloroplasts
51
How do eukaryotes differ from prokaryotes?
```
They have a true nucleus and cytoplasm organelles enclosed within a plasma membrane.
Organelles are specialized.
Tend to 100 times bigger.
Contain much more DNA.
More variety of domains.
```
52
What is the plasmadesmata?
Pores between plant cell walls that allow molecules and communication signals to pass between individual plant cells
53
What is subcellular fractionation?
Centrifugation used to isolate the different parts of the cell from each other
54
Who discovered the nucleus and when?
1820s Robert Brown
55
What is the nuclear envelope?
Separates the nucleus from the cytoplasm, consists of two membranes. The innermembrane and the outer membrane; each made of phospholipid bilayers.
56
What are nuclear lamina?
A network of protein filaments that reinforce the nuclear envelope in animal cells
57
What is nucleoplasma?
The liquid or semi liquid substance within the nucleus
58
What is the nucleoli?
A nuclear structure that contains genetic codes ribosomic RNA, also the site of ribosomal subunits synthesis
59
What are the relaxed and compacted regions of chromosomes called?
Euchromatin is the relaxed region, heterochromatin is the compacted region
60
What is a semi autonomous organelle?
This is an organelle that cannot exist independently but is able to synthesize some of its own proteins.They also have double membranes and divide by binary fission.
61
What does the mitochondria do and where did the specific actions occur in the mitochondria?
Convert oxygen and nutrients into ATP and where cellular respiration occurs. ATP generating reactions occur in the cristae and matrix which is the inner membrane
62
What is Endosymbiosis and why is it important?
Endosymbiosis is the process of when a cell absorbs a prokaryotic cell through the process of evolution the absorb cell becomes an organelle.
This is the origin of the mitochondria
63
What is the Endomembrane system?
Is a group of membranes and organelles in eucaryotic cells that work together to modify, package, and transport lipids and proteins. Includes enclosed organelles and divides the cell into discrete compartments.
64
What are all the components of the Endomembrane system?
Outer membrane of the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, secretory vesicles, vacuoles and plasma membrane
65
What is the origin of Endo membrane’s?
Emerged during Endo symbiosis by endocytosis cell Inc. membranes
66
What are the single membrane or double membrane structures?
Single membrane structures: Golgi apparatus, endoplasmic reticulum vacuole, lysosome
Double membrane structures: mitochondria, chloroplasts, and nucleus
67
What is the function and components of ribosomes?
A large structure composed of ribosomal RNA; the site of translation of mRNA into polypeptide chains which is the synthesis of proteins. Consists of two major subunits the small reads the mRNA and large joins the amino acids carried by a transfer RNA to form a polypeptide chain.
68
What is petidyl transferase?
This is an enzyme in ribosomes that forms peptide bonds between adjacent amino acids carried by tRNAs
69
After proteins are made on free ribosomes in the cytosol where do they go and what do they do?
They can remain in the cytosol, pass through the nuclear pores into the nucleus or become part of the mitochondria, chloroplast, the cytoskeleton, or other cytoplasmic structures.
70
What happens to proteins that enter the nucleus?
Proteins that enter the nucleus become parts of the chromatin, by the nuclear envelope (lamins) or remain insulation in the nucleoplasm
71
What is the structure and functions of the endoplasmic reticulum?
The ER is an extensive interconnected network of membranes channels and cisternae (membranes that surround spaces called lumen), surrounded by a phospholipid membrane. The ER acts as highways or roads, framework for transportation of cellular materials.
72
What is the difference between the rough endoplasmic reticulum and smooth endoplasmic reticulum?
The rough ER has many ribosomes attached on its outer surface, the smooth ER does not.
These ribosomes are also on the outer membrane of the nuclear envelope, proteins synthesized by these ribosomes enter the space between the two nuclear envelope membranes and move to the ER.
Smooth ER is connected directly to the nuclear envelope.
Glycogenolysis (converts glucose 6 phosphate to glucose) occurs in the SER. It is also responsible for the synthesis of lipids and regulation of osmosis.
73
How are lipids transferred?
Lipids can defuse to the nuclear envelope from the ER membrane or they can be transported by vesicles to the Golgi, lysosomes, vacuoles, or plasma membrane.
74
What is detoxification in the smooth endoplasmic reticulum?
Detoxification Chemical reactions are performed in the SER membrane by enzymes
75
What are the 3 main functions of the smooth endoplasmic reticulum?
1 site of lipid and steroid biosynthesis
2 metabolism of foreign chemicals
3 site of glycogen hydrolysis in mammals
76
What is the Golgi complex?
1 instructions for building proteins leave the nucleus and enter the cytoplasm
2 proteins are assembled from amino acids by ribosomes attached to the ER or free in the cytosol
3 The endoplasmic reticulum sends proteins to the Golgi apparatus and other places in the cell if needed
4 The Golgi apparatus creates secretory vesicles which send out the contents of the vesicles
5 The Golgi apparatus also produces lysosome vesicles which are enzymes that break down old or damaged organelles
6 waste products are excreted by endocytosis vesicles
77
What is the Golgi apparatus?
A stack of flattened membrane is sacs (cisternae) and vesicles to transport proteins between Stacks. Stacks contain different enzymes. Generally 4 to 8 cisternae. Cis are the nearest to the endoplasmic reticulum, medial are central layers, and trans are furthest from the endoplasmic reticulum.
78
What is the function of the Golgi apparatus?
Sort, modify, and process proteins and lipids for secretion into vesicles for delivery to targeted destinations
79
What do proteolytic enzymes do?
Cut proteins into smaller polypeptides
80
What are the four different directions of proteins after entering the Golgi apparatus from the ER?
Stay in the Golgi
Transported by vesicles to a lysosome in animal cells or to a vacuole in plant cells
To the plasma membrane
Or to the exterior of the cell by exocytosis
81
What are lysosomes and what do they do?
Lysosomes are small membrane-bound vesicles containing hydrolytic enzymes that digest complex molecules, cells recycle the subunits of these molecules
The enzymes inside lysosomes are synthesized in the rough endoplasmic reticulum.
82
Where do lysosomes come from?
Lysosomes are bud into the cytoplasm by the Golgi apparatus
| Lysosomes are found in animals and not plants
83
What are phagocytes and what is autophagy?
Phagocytes are vesicles that engulf and digest food molecules or materials.
autophagy is the process of vesicles cleaning out damaged organelles
84
What are plastids and the different kinds?
Plastids are semi autonomous (contain own DNA) organelles found in the cells of plants and algae.
Chloroplasts are yellow green plastics and the site of photosynthesis.
Chromoplast are coloured plastids that synthesize and contain other pigments
And leucoplast are colourless plastids that store starch or fat or protein
(For example amyloplasts, elaioplasts and proteinoplasts)
85
What are the components of chloroplasts?
Chloroplasts are surrounded by an outer boundary membrane and an inner boundary membrane which completely enclose an inner compartment the stroma.
Within the stroma is a third membrane system consisting of flattened, closed sacs called thylakoids. Thylakoids are stacked and form Grana
86
What are central vacuoles and their functions?
Large vesicles that perform specialized functions unique to plants.
Store salts, organic acids, sugars, storage proteins, pigments, and in some cells waste products.
In mature plants takes up 90% or more of the sales volume. The tonoplast is the membrane that surrounds the central vacuole and Contain transport proteins that move substrates into and out of the central vacuole
Pigments concentrated in the vacuoles produce colours of many flowers
87
What is the cell wall made of?
Cellulose fibres
The primary so wall is relatively soft and flexible, the secondary cell wall consist of additional layers of cellulose fibres and branched carbohydrates
88
What is the middle lamella and what is it made of?
The middle lamella is a layer of polysaccharides that holds the walls of adjacent cells together. The polysaccharide is called pectin
89
What is the plasmodesmata and its purpose?
Perforate the primary and secondary cell walls. Plasma membrane lined channels that connect the cytosols of adjacent cells together. This allows ions in small molecules to move directly from one cell to another through the cytosol
90
What is cytosol?
The cytosol, also known as intracellular fluid or cytoplasmic matrix, is the liquid found inside cells. Not to be confused with cytoplasm, which includes the organelles floating inside
91
What is the cytoskeleton and its function?
Interconnected system of protein fibres and tubes that extends throughout the cytoplasm, present in all eukaryotic cells.
The cytoskeleton maintains a sales characteristic shape and internal organization, and functions in movement
The cytoskeleton of animal cells contains microtubules Intermediate filaments and microfilaments
92
What are microtubules and what are their functions?
Microtubules are built of proteins called Tubulin. Microtubules help control cell shape, chromosome sorting, organelle positioning, and cell mobility.
93
Motor proteins use ATP as fuel to carry vesicles, organelles, and use spindles to move chromosomes along microtubules. What are the names of these two motor proteins?
Kinesins and dyneins
94
What motor proteins can be found on microfilaments?
Myosins
95
What direction do kinesins and dyneins transport cargo along microtubule filaments?
Nearly all Kinesins move cargo toward the positive end of the microtubules, whereas Dyneins transport cargo towards the negative end
96
What are flagella and Cilia?
Flagella and Celia are elongated, motile structures that extend from the cell surface. Cilia or shorter than flagella and occur in greater numbers
Movements of flagellum push a cell through a watery medium, and Cilia move fluids over the cell surface
97
Flagella and Celia are constructed from microtubules. What is the structure of a flagella?
A circle of nine double microtubules surrounds a central pair of single microtubules, forming a 9+2 complex
98
What is the centrosome and what is it made of?
At the midpoint of the cell centre are 2 short, barrel shaped structures also formed from microtubules called centrioles.
Two centrioles make up a structure called the centrosome.
They are surrounded by proteins called pericentriolar material or PCM
The centrosome is the main microtubule organizing centre (MTOC) and regulates cell cycle progression
99
What is microtubule radiation?
This is when spindle microtubules that radiate outward from the central zone separate and move chromosomes during cell division
100
What are intermediate filaments and what do they do?
Intermediate in size between microtubules and microfilaments. Intermediate filaments help cell shape, provide mechanical strength, and anchor cell membranes
101
What are the narrowest filaments of the cytoskeleton? What are they made of? And what is their function?
Microfilaments are made of actin fibres. They function in cell shape, muscle contraction (with myosin), movement and formation of an amoeba pseudopodia, intracellular transport of nutrients/ proteins/ organelles by cytoplasmic streaming. Lastly divide the cytoplasm during telekinesis
102
What is the structure of the cell membrane?
The cell membrane is defined as an asymmetric lipid bilayer of phospholipids with embedded proteins and cholesterol
103
Are cell membranes rigid?
No! The molecules are not locked into place. Consists of proteins that moves around with a mixture of lipids that has the consistency of oil.
The lipid molecules in the membrane are a highly dynamic structure
104
What is the “fluid mosaic model” aspect of a cell membrane?
The fluid Mosaic model refers to the fact that most membranes contain an assortment of proteins involved in transport and attachment, signal transduction, and diverse other processes such as electron transport that remain mobile in the membrane
105
Phospholipids are the dominant lipids in the cell membrane. What is the lipid composition of the cell membrane?
The head group consists of glycerol link to one of several types of alcohols or amino acids by a phosphate group. The table group consists of two long chains of hydrocarbons (fatty acids)
106
Which end of the phospholipid by layer is hydrophobic and which end is Lipophilic?
The head group of the membrane phospholipids is highly hydrophilic, meaning that it has a higher affinity for the water based environments of the extracellular fluid and the intracellular fluid’s.
The hydrocarbon fatty acids that form the tale of the phospholipids are highly lipophilic (or hydrophobic) meaning they reject water
107
Explain the literal structure of a bilayer.
The fatty acid tails form the internal part, meaning they faced each other. The hydrophilic heads face the exterior and interior environments that are exposed to water and environments.
Simplified: tails inside membrane facing each other and heads making inner and outer surfaces if membrane
108
What does amphipathic mean?
Hint: membranes
Contains both a hydrophilic regions with polar head groups in a hydrophobic region with long fatty acid chains (in the case of membranes)
109
What is the difference between micelles, liposomes, and the lipid bilayer?
Micelles are a phospholipid molecules that arrange themselves into a spiracle form when are in an aqueous solution.
Liposomes our spherical shape vesicles composed of more than one phospholipid by layer that closely resembles the structure of cell membranes. In the liposome an inner membrane compartment is formed, facing the internal water environment.
The lipid bilayer is a thin polar membrane made of two layers of lipid molecules that enclosed a water
110
Why is maintaining proper fluidity critical to membrane function?
Organisms must adjust the fatty acid composition as a mechanism of adaptation to environmental changes. Influenced by lipid composition and temperature
111
What makes a phospholipid tail saturated or unsaturated and how does this affect bilayer fluidity?
Saturated tails have no double bonds and have straight, and non-kinked tails.
Unsaturated tails have double bonds and crooked, kinked tails
Saturated fatty acid tails are arranged in a way that maximizes interactions between the tales. These interactions decrease bilayer fluidity.
Unsaturated fatty acids have more distance between the tails and there’s fewer intermolecular interactions and more membrane fluidity
112
How does temperature affect fatty acid composition?
At lower temperatures phospholipids in the bilayer do not have sufficient kinetic energy and they clustered together more closely. This increases intermolecular interactions, decreases membrane fluidity, and the phospholipid pack and form highly viscous semi solid gel
At high temperatures phospholipids have enough kinetic energy to overcome the intermolecular forces holding the membrane together which increases membrane fluidity.
113
What are desaturases ?
The enzyme that produces unsaturated fatty acids
| bilayer
114
How does cholesterol influence membrane fluidity?
Cholesterol has a highly hydrophobic tail that is located between the fatty acid tails, the hydrophilic end phase the hydrophilic head of the phospholipid.
Cholesterol works as a buffer to regulate the fluidity of the membrane by controlling the movement of the various cell membrane components based on its concentrations.
115
Why does cholesterol production increase in response to cold temperature?
At high temperatures cholesterol inhibits the movement of phospholipid fatty acid chains, reduces permeability to small molecules, and reduces membrane fluidity.
At low temperatures cholesterol stimulates the movement of phospholipids, increases permeability and membrane fluidity, and cholesterol access and antifreeze maintaining the fluidity of the membrane at low temperature
116
What are integral membrane proteins and peripheral membrane proteins?
Integral membrane proteins interact with the membrane hydrophobic core and are a permanent part of a cell membrane and can either penetrate the membrane or associate with another protein on the other side.
Peripheral membrane proteins interact with the membrane hydrophilic surface and the transiently associated with the cell membrane
117
What are the three key functions of membrane proteins?
Transport proteins, signal transduction proteins, and cell adhesion molecules
118
There are _________ protein transmembrane receptors (serpentine receptors) and ion channels in the membrane
Seven
119
What are ion channels?
Ion channels are performing membrane proteins that allow ions to pass through the channel poor. The functions is gating the flow of ions across the membrane
120
What are peripheral membrane proteins?
Peripheral membrane proteins are molecules temporarily associated to the membrane. Most are located on the cytoplasmic side of the membrane.
These proteins attached integral membrane proteins by non-covalent linkage. They do not interact with the hydrophobic core of the membrane. They are to regulate cell signaling and sometimes form part of the cytoskeleton
121
Do molecules such as oxygen and carbon dioxide diffuse rapidly or slowly across the cell membrane?
Rapidly
122
Do molecules such as ions charged molecules and macro molecules move across the cell membrane easily?
No. The membrane is impermeable to polar and charged molecules
Membranes are permeable to nonpolar or hydrophobic molecules like lipids as well as to small molecules like oxygen and carbon dioxide; but are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides
123
What is diffusion and osmosis?
Diffusion is the net movement of molecules from a region of high concentration to a region of lower concentration. The movement of molecules along a concentration gradient.
Osmosis is the diffusion or movement of solvents through a semi permeable membrane, in which solute cannot pass this barrier.
124
Why are diffusion and osmosis important?
By diffusion water and other molecules move across the phospholipid by layer by channels in transporters. By osmosis water moves in and out of the cell.
125
What’s the difference between passive and active transport?
Passive transport relies on the kinetic energy of molecules in solution, therefore it is highly dependent on the temperature of the system. Such as simple diffusion and facilitated diffusion.
Active transport requires energy in the form of ATP
126
What is a major factor of the rate of diffusion?
Concentration gradient: the larger the gradient, the faster the rate of diffusion
127
What is facilitated diffusion?
Also known as facilitated transport or passive mediated transport. Is the process of spontaneous passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins. Does not require ATP energy
128
Is facilitated diffusion saturable and what does this mean?
Yes. When the concentration gradient falls to zero, facilitated diffusion stops and is saturated.
129
Which passive Transport can reach a plateau?
Facilitated diffusion can be saturated and therefore reach a plateau. Simple diffusion never reaches a plateauBecause it takes place over the entire membrane, not specific proteins/proteins channels
130
What is osmosis?
Osmosis is the passive passage of solvent (liquid) through a selectively permeable membrane into a compartment having a greater solute (dissolved solid) concentration in the direction that tends to equalize the saw you concentration on both sides.
131
What is the meaning of hypotonic and hypertonic?
If the solution surrounding a cell contains dissolved substances at lower concentrations then in the cell, the solution is said to be hypotonic to the cell. If the solution contains higher concentration of dissolved substances, the solution is hypertonic.
132
What is turgor pressure in plant cells?
When the cell is in a hypotonic solution water enters by osmosis and causes swelling, the cell wall of plant cells prevents bursting and creates turgor pressure.
133
Do both animal and plant cells shrink in hypertonic solutions?
Yes ma’am
134
What is it called when the concentration of solutes inside and outside of the cell is equal?
Isotonic
135
What is tonicity?
The ability of extracellular solution to make water move into or out of the cell by osmosis
136
Maintaining isotonicity comes with a ______ cost
Energetic
Note: transport of sodium out of the cell is essential, regulate water rushing inward
137
What is an aquaporin?
Aqua Pourin is an integral membrane proteins that form spores in the membrane.The Aquaporin channel is very narrow and allows for the single file movement is about 1 billion water molecules every second;Does not allow the diffusion of ions including protons
138
How to Aquaporins protect the flow of protons?
The presence of positive charges in the centre of the channel repel the transport of protons
139
Ion channel proteins are transporters that can switch between open, clothes, and intermediate states. How is this possible?
Iron gate may be open or closed by changes in voltage across the membrane for instants or by binding signal molecules
140
How do you carrier proteins transport cargo molecules across the membrane?
Each carrier protein binds a single specific solute and transports it across the lipid bilayer
141
Why does active membrane transport require ATP energy?
Because it moves substances against their concentration gradients
142
What is the difference between primary active transport and secondary active transport?
Primary active transport moves positively charged ions by a sodium potassium pump. Sometimes hydrogen pumps or calcium pumps but these pumps work in a similar fashion.
Secondary active transport moves organic molecules against their concentration gradient and indirectly uses energy from ATP derived from the electrochemical gradient generated by the sodium potassium pump
143
In a single cycle of the sodium potassium ATP pump _______ sodium ions are extruded from the cell and ______ potassium ions are imported into the cell
Three, two
144
What is membrane potential?
When the difference in ion concentration, developed by the potassium sodium pump, creates a difference of charges between the exterior and the interior part of the membrane
145
What is an electrical gradient and how is it related to secondary source of energy?
Electrical gradient Are created by theDifference in charges on sides of the cell membrane. They provide energy to transport glucose, amino acids, and other nutrients by secondary active transport against concentration gradients
146
What are the two forms of secondary active transport?
Symport: The transported solute moves in the same direction as the gradient of the driving ion; a driven ion, such as sodium, and a molecule moves through the membrane channel in the same direction
Antiport: the transported solute move in the direction opposite from the gradient of the driving ion; in one direction the ion provides the energy for the active transport of another molecule or ion that moves in the opposite direction
147
What are the three main functions of the sodium potassium pump?
1 To maintain isotonicity and cell volume by constantly pumping sodium out of the cell
2 to create a difference of charges between the exterior and the interior, termed membrane potential
3 to create an electrochemical gradient that provides the energy that is used by the secondary active transport move other molecules against a concentration gradient
148
What are exocytosis and endocytosis?
Exocytosis is an energy dependent secretory process in which large molecules in bulk are transported out of the cell
Endocytosis is the counterpart of exocytosis. And energy dependent mechanism of bulk incorporation of large hydrophilic molecules that cant pass the membrane
149
What are the three types of endocytosis?
hint pinocytosis, receptor mediated endocytosis, and phagocytosis
Pinocytosis is the invagination of the cell membrane to form a pocket, which then pinches off into the cell to form a vesicle sealed with a large volume of extracellular fluid and molecules within
Receptor mediated endocytosis it’s a process by which cells absorb metabolites, hormones, proteins and sometimes viruses by the inward budding of the plasma membrane
Phagocytosis is the process by which cells bind and internalize large particles. These processes involved the uptake of larger membrane areas into internal compartments termed phagosome
