Biology Test #2
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- What is the simplest collection of matter that can live?
- Cells
-
-pass visible light through a specimen
-magnify cellular structures with lenses - Light Microscopes
- What is the measurement used in microscopy?
- micrometer
- -focus a beam of electrons through a specimen or onto its surcace
- electron microscopes
- provides for detailed study of the surface of a specimen
- scanning electron microscope
- provides for detailed study of the internal ultrastructure of cells
- transmission electron microscope
- takes cells apart & separates the major organelles from one another
- cell fractionation
- used to fractionate cells into their component parts
- the centrifuge
- when do cell parts separate?
- less dense cell parts will separate from more dense cell parts
- have internal membranes that compartmentalize their functions
- eukaryotic cells
- several basic features that all cells have in common
-
-pasma membrane
-cytosol (a semifluid substance)
-organelles
-chromosomes & ribosomoes - site of protein synthesis
- ribosomes
-
-do not contain a true nucleus
-no nuclear envelope
-dna located in nucleoid
-have a cell wall - prokaryotic cells
-
-membranous nuclear envelope
-generally quite a bit bigger
-have organelles surrounded by membranes - eukaryotic cells
- have a higher surface to volume ratio which facilitates the exchange of materials into and out of the cell.
- smaller cells
-
-functions as a selective barrier
-allows sufficient passage of nutrients & waste - plasma membrane
-
-phospholipid bilayer
-cholesterol
-proteins - major components of the plasma membrane
-
-cell walls
-chloroplast
-central vacuole - things that plants have
- eukaryotic cell's genetic instructions are housed in the
- nucleus
- genetic instructions for which type of cell are housed in the nucleus?
- eukaryotic cells
- the nucleus contains most of the genes in which type of cell?
- eukaryotic
- what contains most of the genes in the eukaryotic cell?
- nucleus
- a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA
- genes
- encloses the nucleus, separating its contents fromt the cytoplasm
- nuclear envelope
- particles made of ribosomal RNA and protein
- Ribosomes
- build proteins in 2 cytoplasmic locates
- ribosomes
- 2 cytoplasmic locates in which ribosomes build proteins
-
-free ribosomes
-bound ribosomes - found floating freely in the cytosol
- free ribosomes
- found attached to the rough endoplasmic reticulum
- bound ribosomes
-
-free ribosomes
-bound ribosomes - proteins synthesize on
- remain in the cell
- free ribosomes
- destined to exit the cell
- bound ribosomes
- various structures in the endomembrane system are related through
-
-direct physical continuity
-transfer of membrane segments known as vesicles - a sac made of membrane insidee of a cell
- vesicle
- the endomembrane system includes
- the endoplasmic reticulum
- accounts for more than 1/2 the total membrane in many eukaryotic cells
- endoplasmic reticulum
- continuous with the nuclear envelope
- the endoplasmic reticulum membrane (er)
- 2 distinct regions of er
-
-rough er
-smooth er -
-contains ribosomes
-produces proteins & membranes (which are distributed by transport vesicles) - rough er
- lacks ribosomes
- smooth er
-
-synthesizes lipids
-metabolizes carbohydrates
-detoxifies poison - functions of smooth er
- broken down in the cells of the liver
- glycogen
- shipping & receiving center
- golgi apparatus
- consists of flattened memranous sacs called cisternae
- golgi apparatus
- side facing the nucleus
- "cis" side
- side facing the plasma membrane
- "trans" side
- receives many of the transport vesicles provided in the rough er
- golgi apparatus
-
-modification of the products of the rough er
-manufacture of certain macromolecules - functions of the golgi apparatus
-
-moves from er to golgi
-coalesces with "cis" side of golgi
-always go to the cis side
-moves from the cis to the trans side
-membranes coalesce each time
-forms & exits golgi
-fuses wtih plasma membrane
- - vesicle proteins within the endomembrane system
- 3 methods of moving substances in or out of the cell
- exocytosis & endocytosis
- materials move out of the cell
- exocytosis
- a membranous sac of hydrolytic enzymes that can digest all kinds of macromolecules
- lysosome
-
-carry out intracellular digestion
-autophage
-apoptosis - 3 processes of lysosome
- involves phagocytosis & lysosomes fuse with food vacuole.
- intracellular digestion
- paramecium: unicellular organism that:
- carries out intracellular digestion
- the cellular uptake of macromolecules & particulate substances by localized regions of the plasma membrane that surround the substance
- endocytosis
- a type of endocytosis involving large particulate substances
- phagocytosis
- macromolecules or substances form vacuoles once inside the cell
- endocytosis
- cytoplasmic extension used for feeding in some cells
- psuedopodia
- food vacuoles are formed by
- phagocytosis
- lysosomes break down damaged organelles within a cell recycles organic molecules
- autophage
- the changes that occur within a cell as it undergoes progammed cell death
- apoptosis
- genetically programmed to break open at a specific time
- lysosomes
- are formed by phagocytosis
- food vacuoles
- pump excess water out of protist cells
- contractile vacuolles
- found in plant cells & hold reserves of importnt organic compounds and water
- central vacuoles
- a complex & dynamic player in the cell's compartmental organization
- the endomembrane system
-
-food
-contracile
-central - types of vacuoles
- change energy from 1 form to anotehr
- mitochondria & chloroplasts
- -sites of cellular respiration
- mitochondria
- glucose molecule is broken down to release energy
- mitochonria
- found in almost all plant & animal cells
- mitochondria
- smootther outer & inner folded into cristae
- mitochondria has 2 membranes
- capture of light energy
- choloroplasts
-
-contail chlorophyll
-site of photsynthesis - chloroplsts
- process in which light energy is converted to the chemical energy in lucose
- photosynthesis
- found in leaves & other green organs of plants & in algae
- chloroplasts
-
-thylakoids
-stroma - parts of chloroplast structure
- membranous sacs
- thylakoids
- internal fluid
- stroma
- a network of fibers extneding throughout the cytoplasm
- the cytoskeleton
- support motility & regulation
- roles of the cytoskeleton
- gives mechanical support to the cell
- cytoskeleton
- involved in cell motility which utilizes motion proteins
- microtubules
- hollow tubes
- microtubules
- shape the cell
- microtubules
- guide movement of organelles
- microtubules
- help separate the chromosome copies in dividin cells
- microtubules
- contain specialized arrangements of microtubules
- cilia & flagella
- locomotor appendages of some cells
- cilia & flagella
- beating pattern
- flagella
- back & forth motion
- ciliary motion
- flagella & ciliary motion
- microtubules
- share a common ultrastructure "9+2" arrangement of microtubules
- cilia & flagella
- 9 pairs make a circle & 2 singles are in the middle
- 9+2 arrangement of microtubules
- built from molecules of the protein actin
- microfilaments
- involved in amoeboid movement & involves the contraction of actin & myosin filaments
- microfilaments
- another form of locomotion by microfilaments
- cytoplasmic streaming
- exhibits selective permeability & allows some substances to cross it more easily than others
- plasma membrane
- states that a membrane is a fluid structure with a "mosaic" of various proteins embedded in it
- fluid mosaic model of membrane structure
- can move iwthin the bilayer
- phospholipids
- flip flop 1 time per month
- lateral movement
- can drift within the bilayer
- proteins
-
-unsaturated hydrocarbon tails (with kinks)
-saturated hydrocarbon tails (more fluid) - phospholipids may have
- unsaturated hydrocarbon tails
- with kinks
- saturated hydrocarbon tails
- more fluid
- affects the fluidity of the plasma membrane
- the type of hydrocarbon tails in phospholipids
- weged between phospholipid molecules in the plasma memrane of animals
- cholesterol
- molecule with 4 interlockig rings (make the membrane less fluid)
- cholesterol
- a collage of diferent proteins embedded in the fluid matrix of the lipid bilayer
- membrane proteins
- penetrate the hydrophobic core of the lipid bilayer
- integral proteins
- appendages loosely bound to the surface of the membrane
- peripheral proteins
- provide a method of moving a particular solute from one side of the plasma membrane to another
- transport proteins
-
-channel
-carrier - types of transport proteins
- may provide a hydrophillic channel across the mebrane that is selective for a particular solute
- channel proteins
- move a solute across when the protein changes shape
- carrier proteins
- a cell's ability to distinguish one type of neighboring cell from another
- cell-cell recognition
-
-sorting of cells into tissues and organs in an animal embryo
-rejection of foreign cells by the immunesystem - importance of cell-cell recognition
- interaction with the surface molecules of other cells
- cell-cell recognition
- interact with the surface molecule of other cells, facilitating cell-cell recognition
- glycoproteins & glycolipids
- a cell must exchange materials with its surroundings
- a process controlled by the plasma membrane.
- lipid soluble and can pass through the membrane rapidly
- hyrdrophobic molecules
- do not cross the membrane rapidly
- polar molecules
- allow passage of hydrophic substance across the membrane
- transport proteins
- molecules move due to
- thermal energy
- diffusion of a substance across a mebrane with no energy investment
- passive transport
- the tendency for molecules of any substance to spread out evenly into the available space
- diffusion
- there's net diffusion (one side gaining) until
- equilibrium (both sides equal) then there's transfer but no side has more than the other at any given time
- net diffusion
- one side gains
- the movement of substances from an area of higher concentration of that substance to an area of lower concentration
- diffusion
- substances diffuse
- down their concentration gradient
- the difference in concentration of a substance from 1 area to another
- concentration gradient
- membane is permeable to
- water not solutes
- water moves from an area of higher concentration of water to an area of lower concentration of water
- osmosis
- water molecules move from an are of
- lower solute concentration to an area of higher solute concentration (this is backwards in diffusion)
-
the ability of a solution to cause a cell to gain or lose water
-has a reat impact on cells without walls - tonicity
- ideally the molarity
- of the solution outside the cell & inside the cell is the same
- if a solution is isotonic
- the concentration of solutes outside the cell is the same as it is inside the cell
- in comparing 2 solutions referrin to the one with a greater solute concentration
- hypertonic
- if the solution outside the cell is hypertonic then
- the cell will lose water
- in comparing 2 solutios- referring to the one with a lower solute concentration
- hypotonic
- if the solution outside the cell is hypotonic to the cell
- the cell will gain water
- an animal cell (hypotonic solution)
- lysed (water goes in)
- water comes in & out
- isotonic (normal)
- water comes out
- shriveled (hypertonic)
- organisms without rigid cell walls living in hypertonic or hypotonic environments
- must have special adaptations for osmoregulation (has to e able to regulate water flow)
- how organisms regulate solute concentrations & balance the gain & loss of water
- osmoregulation
- name the osmoregulatory device in paramecium
- contractile vacuole
- help maintain water balance
- cell walls
- if a plant cell is turgid
- it is in a hypotonic envionment it is very firm a healthy state in most plants
- if a plant cell is flaccid (limp)
- it is in an isotonic environment
- if a plant cell is in a hypertonic solution
- the cell will lose water to its surroundings & shrink
- water will diffuse
- out of the cytosol & large central auole
- as the plant cell contents shrviels
- its plasma membrane pulls away from the wall
- when the plasma membrane pulls away from the wall
- plasmolysis
- if something wilts
- plasmolysis has occurred
- water comes in when
- turgid (normal
- water coes in & out when
- flaccid
- water comes out when
- plasmolyzed
- can predict the direction in which water will flow
- water potential
- water potential is governed by
- solute concentration & applied pressure
- has to do with cell wall
- applied pressure
- gives scientists a numberical value
- water potential
- pure water has the water potential & molarity
- zero
- adding solutes
- lowers the water potential
- if the water potential of pure water is zero adding solutes
- makes the water potential negative
- water moves
- from an area of high water potential to an area of lower water potential
- diffusion/osmois & facilitated diffusion
- 2 types of passive transport
- facilitated diffusion
- no energy & with a concentration gradient
- facilitated
- to help-move faster
- speed the movement of molecules across the plasma membrane
- transport proteins
- specific for the solute & specific binding sites
- transport proteins
- provide corridors that allow a specific molecule or ion to cross the membrane
- channel proteins
- undergo a subtle change in shape that translocates the solute binding site across the mebrane
- carrier proteins
- uses energy to move solutes against their gradients
- active transport
- if you go up a tree
- it takes action (kinetic energy)
- if you're on limb & step off
- it's passive (doesn't take any energy)
- enables a cell to maintain internal concentrations of small molecules that differ from concentrations in its environment
- active transport
- if it requires energy it's in the form of
- atp
- an area of lower concentration to an area of higher concentration
- carrier proteins
- a certain concentration of sodium & potassium ions
- all cells must maintain
- a higher concentration outside the plasma membrane
- sodium
- a higher concentration inside the plasma membrane than outside
- potassium
- for every 3 pumped out of the cell there has to be 2 pumped into the cell
- for every 3 cytoplasmic sodium pumped out of the cell there has to be 2 extracellular potassium ions pumped into the cell
- one type of active transport system
- sodium potassium pump
- higher to lower
- passive transport
- if something goes across the bilayer from higher to lower
- diffusion
- transport & carrier proteins
- facilitate diffusion
- lower to higher concentration
- active transport
- more of 1 type of chemical on one side than on another
- chemical gradient
- the voltage difference across a membrane
- membrane potential
- the inside of the cell
- is negative compared to the outside
- two forces drive
- the diffusion of ions across a membrane
- caused by the concentration electrical gradient of ions across a membrane
- electrochemical gradient
- examples of elctrochemical gradient mechanisms
-
-sodium-potassium pump
-prton pump - pumps protons or hydrogen ions
- proton pump
- 2 examples of electrochemical gradient mechanisms
- both are examples of active transport
- bulk transport across the plasma membrane occurs by
- exocytosis & endocytosis
- exo
- out
- endo
- in
- transport vesicles migrate to teh plasma membrane, fuse with it, & release their contents.
- exocytosis
- the cell takes in macromolecules by formng new vesicles from the plasma membrane
- endocytosis
- phagocytosis, pinocytosis, receptor
- 3 types of endocytosis
- large macromolecules are taken in
- phagocytosis
- cell drinking (particles of fluid are taken in)
- pinocytosis
- cell mediated
- receptor
- receptors on outside
- receptor endocytosis
- 80% genetics
- metabolism
- the totality of an organisms chemical reactions
- metabolism
- the transformation of one type of matter to another type of matter
- law of thermodynamics
- the transformation of oe type of energy to another type of energy
- laws of thermodynamics
- has many steps that are each catalyzed by a specific enzyme
- metabolic pathway