UNIT 1 Flashcards
What is life?
It’s an organized unit capable of metabolism, reproduction and evolution.
What is metabolism?
It’s the chemical reactions in the body’s cells that change food into energy.
What is reproduction?
Its a process and which an individual cell/ organism make new cells/ organisms
What is evolution?
It is how living things change over time and how new species develop.
Cell metabolism is….?
its total chemical activity, and consists of thousands of individual chemical reactions.
These reactions in the cell/organisms must be ….?
…. coordinated for a cell/organism to function.
What provides control and coordination in the cell?
Genes
What is ATP?
It provides energy to the cell.
What is anabolism?
It grows and builds.
What is catabolism?
It breaks down.
What produces less heat (anabolism or catabolism)?
Anabolism since building up takes less energy then breaking down.
What is the cycle of the cell (broad)?
Larger molecules go through catabolism which produces small molecules which as well go through anabolism and it restarts.
What is homeostasis?
Its the maintenance of a stable internal condition.
The internal environment of a cell/organism must remain …what?
….within a given range of physical and chemical conditions for that cell/organism to remain healthy.
What is reproduction?
Its a process by which an individual cell/organism makes a new individual cell/organism
What is a major characteristic of life (with variation)?
Reproduction
What leads to evolution?
The combination of reproduction and errors in the duplication of the genetic material.
Variations in the physical environnement helps with what?
Drive the diversification of life
What is an adaptation?
Characteristic that allows a organism to adapt to its environnement.
What is sexual reproduction?
The combining of genetic information from two cells
How does sex increase the rate of evolution?
- produce genetically variable offsprings
- offspring made through sexual reproduction have an advantage over asexual re production
Darwin called the differential survival and reproductive success of individuals what?
natural selection
life arose from what?
non-life
what led to the appearance of life about 4 billion years ago?
Chemical evolution
Random inorganic chemical interactions eventually produced what?
molecules that were able to make copies of themselves
Around 3.8 billion years ago certain molecules became enclosed in “compartments”, or cells. What are they called?
prokaryotic cells(first ones)
Cells can do what?
capture energy, replicate themselves and evolve.
For how long all organisms were unicellular, confined to the oceans, and protected from (ultraviolet) radiation.? UV
For 2 billion years
some prokaryotic cells acquired the ability to photosynthesize. How long ago?
about 2.5 billion years ago
Ozone has the property of…..
preventing excess UV light from the sun from reaching Earth.
What is the first unifying theory of biology?
cell theory
What does the cell theory state?
▪Cells are the fundamental units of life.
▪All organisms are composed of cells.
▪All cells come from preexisting cells.
What is implied in the cell theory?
▪The functions of all cells are similar.
▪The origin of life was the origin of cells.
▪Life is continuous.
How small is a cell?
<200um
Why are cells so small?
because a high surface-area-to-volume ratio is essential.
The surface area of a cell determines what?
the number of substances that can pass the cell boundary per unit time.
The volume determines what?
the amount of chemical activity in the cell per unit time.
As a cell volume increase what else increases?
chemical activity along with the need for resources and waste removal
Large organisms consist of what? ( when the surface area becomes limited)
many small cells
The two types of cells?
prokaryotic and eukaryotic
Prokaryotic cell is a characteristic of what domains?
Bacteria and Archaea.
An organism in the bacteria and archaea domain is exclusively what?
unicellular.
Prokaryotic cell lacks what?
internal compartments
Prokaryotic cell have a nucleus that is not ..? ( called nucleoid region)
membrane- bound
Eukaryotic cell is characteristic to four kingdoms of domains what?
Protists, Plants, Fungi, Animals.
Organism in the eukarya domains may be …?(cells)
unicellular -or- multicellular
Eukaryotic cell have many…? (In their cells)
many membrane- bound compartments (including a double- membrane-bound nucleus containing DNA).
All prokaryotic cells have …? ( the different things within their cell)
▪plasma membrane
▪nucleoid region with one circular strand of DNA
▪cytoplasm containing dissolved enzymes, water,
and small molecules
▪70S (small) ribosomes for making proteins
Most prokaryotes have …?
▪cell wall (outside the plasma membrane) made
of peptidoglycan
Some prokaryotes have…?
▪outer membrane (outside the cell wall)
▪capsule (outside cell wall or outer membrane)
▪photosynthetic pigments (i.e., cyanobacteria)
What cell has some rotating flagella that cause movement of the cell?
prokaryotes
What cell has pili (hairlike structure projecting from the surface)?
prokaryotes
What can help bacteria adhere to one another to other cells or to environmental surfaces?
pili
Like prokaryotic cells, eukaryotic cells have…?
a plasma membrane, cytoplasm, and ribosomes
Tho eukaryotic cells are …? (Size)And contain…?(in their cell)
▪eukaryotic cells are larger (up to 10x),
and
▪contain many membrane-enclosed
compartments called organelles.
What is the largest organelle in a eukaryotic cell?
nucleus usually
the nucleus surrounded by…?
the nuclear envelope (double membrane bound: 1 outer, 1 inner)
Within the nucleus, the nucleolus is where what is made?
ribosomes
Ribosome are sites to what synthesis?
protein synthesis
Eukaryotic ribosome are…? (Large or small)
large
ribosome are molecules made of what? (2 things)
RNA & proteins.
ribosome are found doing and/or attached to what?
free-floating -or- attached to RER.
What controls the movement of the molecules between the nucleus and cytoplasm?
Nuclear pores
What is in the nucleus and associated with protein forms chromatin?
DNA
What is diffuse within the nucleus but condenses to form visible chromosomes?
Chromatin
What system includes the plasma membrane, nuclear envelope, endoplasmic reticulum, Golgi apparatus and lysosomes?
endomembrane system
What shuttle substances between the various components?
Tiny, membrane-bound vesicles
What is the endoplasmic reticulum? (ER)
Network of membranes in the cytoplasm; large surface area.
What is the rough endoplasmic reticulum?(RER)
The part of endoplasmic reticulum that has 80S (large) ribosomes that synthesize proteins. It also modifies them, folds them, and transports them to other regions.
What is the smooth endoplasmic reticulum? (SER)
The part of endoplasmic reticulum that lacks ribosomes and is associated mostly with synthesis of lipids, and some detoxification.
What is the Golgi apparatus? And his “job”?
its composed of flattened sacs (cisternae) and small vesicles.
▪Receives proteins from the RER—can further modify them.
▪Packages and sorts proteins.
▪In plant cells, polysaccharides for the making of cell walls are synthesized here.
The cis region of the Golgi do what?
receives vesicles from the ER.
The trans region of the Golgi do what?
releases vesicles that are moved to the plasma membrane or other organelles.
What is lysosomes? (what do they contain?)
They contain digestive enzymes that hydrolyze macromolecules into monomers.
The primary lysosomes are made in …?
in the Golgi apparatus.
When is a phagosome formed?
when food molecules enter the cell by phagocytosis
How is secondary lysosomes formed?
Phagosomes fuse with primary lysosomes
What enzyme hydrolyze the food molecules?
Hydrolytic enzymes
Waste in the cell are ejected by….?
exocytosis
What are mitochondria organelle? where is it found as well?
They are double-membrane-bound organelles found in animals, plants, fungi, and some protists.
What do mitochondria contain?
one circular strand of DNA, 70S (i.e., small) ribosomes, and some enzymes.
What is the mitochondria job?
energy contained in food molecules is transformed into energy-rich ATP molecules during a metabolism called cellular respiration.
What is chloroplast?( where does it occur? and what is in this cell?)
it occur in plants and in photosynthetic protists (i.e., algae).
- These are double-membrane-bound organelles.
- They contain one circular strand of DNA, 70S (i.e., small) ribosomes, and some enzymes.
Chlorophyll and other pigments use light to make…?
energy to make ATP molecules and sugars during a metabolism
What is this metabolism called?
photosynthesis.
What are the cells surviving with smaller prokaryotic cells within them?
early eukaryotic cells
Atoms, molecules, cells, tissues, organs, organisms, population, communities and biosphere what can this be visualized as?
hierarchy of units in biology
All organism on earth today descended from what?
an original unicellular organism
What tree biologists assembled using data from a variety of source?
Tree of Life
What are the 3 major domains in the tree of life?
▪Bacteria and Archaea (prokaryotes)
▪Eukarya (eukaryotes).
Each species are identified by scientific names a binominal what is the first and second name called? (Scientific names)
▪ The first name (the genus name) refers to a group of species that share a recent common ancestor.
▪The second name (the specific epithet) identifies a single species within the genus.
What is the scientific name for modern humans?
Homo sapiens
What is the taxonomic classification? (The list )
Kingdom Phylum Class Order Family Genus Species
What are the main parts to the scientific method?
- Making observations
- Asking questions
- Forming hypotheses (i.e., tentative answers to the questions)
- Making predictions based on these hypotheses (ex., if…, then…)
- Testing the predictions by conducting experiments (i.e., materials and methods)
When can something be called a theory?
If the results of continued testing support the hypothesis
What are controlled experiments?
They are the most popular experiments executed by scientists.
What do the scientists manipulate?
a single variable that is predicted to cause differences between groups.
The variable is manipulated in an… ? And the results are compared with data from an …?
“experimental” group
un-manipulated “control” group.
What is the independent variable?
the variable being manipulated.(What do I change?)
What is the dependent variable?
the response that is measured. (What do I observe?)
What is the controlled variable?
one or more variables that are held constant in both the experimental and control groups.
When are the statistical test applied?
to the data to determine the probability of getting a particular result.
statistical test eliminate what?
the possibility that results are due to random variation.
The presence of what matter was critical in making conditions suitable for life?
water
All matter is composed of ….?
atoms
Each atom consists of ….?
a proton and one electron at least
Each element consists of ..?
only one type of atoms
All atoms have the same number of protons but can differ in neutrons what are those called?
isotopes
The place a atom travel..?
an orbital
A chemical bond is ..?
its an attractive force that links two atoms together.
A covalent bond is …?
formed by sharing of a pair of electrons between two atoms.
Convolent bonds are the …?
strongest bonds.
What is called the attractive force that an atom exerts on electrons?
electronegativity
The unequal sharing of electrons cause a partial negative and partial positive resulting in a ….?
polar covalent bond
Polar molecules are …?
Molecules that have polar covalent bonds
Hydrogen bonds involve hydrogen and …? (4 atoms)
oxygen, nitrogen, fluorine or chlorine.
Hydrogen bond are the attraction between…?
The - portion of one molecule to the + portion of another molecule
Hydrogen bonds do not share what?
electrons
Polar molecules tend to be…?
hydrophilic.
Substance that are ionic or polar often…?
dissolve in water due to hydrogen bonds.
Non polar are called..?
hydrophobic
Non polar molecules tend to…?
group with other nonpolar molecules.
Non polar molécules are also attracted to each other what are the weak attractions formed called?
van der Waals forces
What is the weakest bond?
van der Waals forces
Due to what does the water have unusual properties?
its shape, polarity, and ability to form hydrogen bonds
Water has a … when frozen?
crystalline structure
Water has a ….. which makes water molecules resist from coming appart from one another?
cohesive strength
The cohesive strength allows what?
the transport of water from the roots to the tops of trees
Because of the cohesive strength present in the water has a ….?
high surface tension
Living organism are …% water?
70
Substance that dissolve in water release an hydrogen ions is called?
acids
Substance that dissolve in water release an hydroxide ions is called?
bases
What group functions as an acid?
carboxyl group
What group functions as a weak base ?
amino group
What acts as both a weak acid and a weak base?
water
What is ph ?
its the measure of hydrogen ion concentration.( between 0-2 its 100X more basic than..)
What are 2 properties that influence the behaviour of molecules?
▪ recognizable functional groups
▪ the existence of isomers of molecules.
Functional group gives what?
specific properties to molecules.
What are the properties of the hydroxyl group?
They are polar molecules with OH at the end. They enable linkage to other molecule by dehydration.
What are the properties of the aldehyde group?
They have H-C=O bond at their end. They are important in building molecules and in energy releasing reactions.
What are the properties of the keto group?
They have a C=O bond in the middle. Its important in carbohydrates and in energy reactions.
What are the properties of the carboxyl group?
They make molecules more acidic. They have an OH-C=O bond at their end.
What are the properties of the amino group?
They make molecules more basic. They have an H-N-H at their end.
What are the properties of the phosphate group?
It makes a highly energetic covalent bond. Its negatively charged.
O
II
There is a O-P-O
I
O
at their end.What are the properties of the sulfhydryl group?
There is a S-H bond at their end. They make a disulfide bond.
What are isomers?
its molecules that have the same chemical formula, but a different structural formula
What are structural isomers?
differ in terms of how atoms are joined together.
What are optical isomers?
are essentially structural isomers that are also mirror images of each other.
What are living things composed of?
the same elements as the inanimate universe.
What are the 2 theories to the origin of life?
▪ Molecules of life came from extraterrestrial sources
▪ Molecules of life resulted from chemical evolution on Earth
What are the 4 major types of macromolecules?
▪ Proteins
▪ Carbohydrates
▪ Lipids
▪Nucleic acids
Are they present in all organisms in roughly the same proportions?
yes
What is the advantage of biochemical unity?
is that organisms acquire needed biochemicals by eating other organisms.
What are macromolecules?
giant polymers.
How are polymers are formed?
by covalent linkages of smaller units called monomers.
How are macromolecules made?
from smaller monomers by means of a condensation (or dehydration) reaction in which an OH from one monomer is linked to an H from another monomer.
What is called the reverse reaction in which the polymers are broken back into monomers?
hydrolysis reaction.
What are proteins?
they are polymers of amino acids. They are molecules with diverse structures and functions.
• Each different type of protein has a characteristic amino acid composition and order.
• Proteins range in size from a few amino acids to thousands of them.
• Folding is crucial to the function of a protein and is influenced largely by the sequence of amino acids.
An amino acids has 4 groups attached to the central carbon atom, what are they?
- Amino group
- carboxyl group
- side chain
- hydrogen atom
There is 20 R group what are they?
▪5 have charged hydrophilic side chains.
▪5 have uncharged hydrophilic (polar) side
chains.
▪7 have hydrophobic (nonpolar) side chains.
▪ Cysteine has a terminal disulfide (—SH—).
▪ Glycine has a hydrogen atom as the R group.
▪ Proline has a modified amino group that forms a covalent bond with the R group, forming a ring.
How are proteins synthesized?
by condensation reactions between the amino group of one amino acid and the carboxyl group of another.
What bond is formed by the grouping of amino group and the carboxyl group?
This forms a peptide linkage.
What is another name for the proteins?
polypeptides
They are 4 levels to a protein structure what are they called?
primary, secondary, tertiary, and quaternary
What is the primary structure of a protein?
The precise sequence (i.e., order) of amino acids
The peptide backbone consists of….?
of repeating units of atoms
What is the secondary structure of a protein?
it consists of regular, repeated patterns in different regions in the polypeptide chain.
The shape of the protein is influenced by what?
hydrogen bonds
What are the 2 common secondary structure?
▪ the a-helix, and;
▪ the b-pleated sheet.
What is the a-helix?
• Is a right-handed coil.
What is the b-pleated sheets?
Form from peptide regions of a single strand that lie
parallel to each other.
What is the tertiary structure?
Bending and folding results in a macromolecule with specific three-dimensional shape.
What is the primary determinant of the tertiary structure? (bonds & forces that can be seen)
▪Disulfide bonds ▪Aggregation of hydrophobic side chains ▪van der Waals forces ▪ Ionic bonds ▪Hydrogen bonds
What is the quaternary structure?
from the ways in which multiple (2 or more) polypeptide subunits bind together and interact.
• This level of structure adds to the three-dimensional shape of the finished protein.
What is crucial to the functioning of protein?
Shape
What can change the shape of a protein?
temperature, pH, salt concentrations, and oxidation or reduction conditions
What is it called when a protein loses its 3-D shape ?
denaturation
What are chaperonins?
its a specialized proteins that help keep other proteins from interacting inappropriately with one another.
What do chaperonins help to do?
• Some chaperonins help folding; some prevent folding until the appropriate time.
What are carbohydrates?(how they are made?)
carbon molecules with hydrogen groups and hydroxyl groups
What is the job of carbohydrates?
- They act as energy storage and transport molecules.
* They also serve as “carbon skeletons” for other molecules.
What are the 4 major categories of carbohydrates?
▪ Monosaccharides are the monomers of carbohydrates; simple sugars.
▪ Disaccharides, which consist of two monosaccharides linked by one covalent bond.
▪ Oligosaccharides, which consist of between 3 and 20 monosaccharides
▪ Polysaccharides, which are composed of hundreds to hundreds of thousands of monosaccharides—starch, glycogen, cellulose
What is the general formula of carbohydrate monomer?
Cn(H2O)n
What is the ratio of the atoms in the general formula of carbohydrate monomer?
ratio of 1 carbon to 2 hydrogens to 1 oxygen.
How is called the condensation reaction?
polymerization
What are the different monosaccharides?
▪ Triose (3-carbon sugars) include glyceraldehyde.
▪ Tetrose (4-carbon sugars) include erythrose.
▪Pentoses (5-carbon sugars) include ribose, deoxyribose.
▪ Hexoses (6-carbon sugars) include the structural isomers glucose, fructose, mannose, and galactose.
What is the preferred energy source of all cells?
glucose
Glucose exists in a…? (shape)
straight chain or ring form.
Monosaccharides bond together in the condensation reaction called…? (name of the bond)
glycosidic linkages
What are disaccharides? (their linkages)
they have just one glycosidic linkage: sucrose, lactose, maltose, cellobiose.
What are ogliosaccharide?
contain more than two monosaccharides. Usually 3-20.
What are polysaccharides? And some examples of them?
giant polymers of monosaccharides connected by glycosidic linkages.
▪ Starch: storage of glucose in plants
▪Glycogen: storage of glucose in animals
▪ Cellulose (i.e., fiber): very stable, good for structural components in plants.
What is not digestible to animals and humans?
fiber is not digestible(β-links)
How can carbohydrates be modified?
by the addition of functional groups:
▪ Phosphate added to one or more hydroxyl (—OH) sites creates a sugar phosphate, such as fructose 1,6-bisphosphate.
▪ Amino groups can be substituted for —OH groups, making amino sugars, such as glucosamine and galactosamine.
Are lipids soluble in water?
no
The insolubility of lipids are from what?
from the many nonpolar
covalent bonds of hydrogen and carbon in lipids
What is the only group of macromolecules that does not consist of polymers?
Lipids
What are lipids made of?
smaller “fatty” molecules such as fatty acids and glycerol
What do fat and oil do?
store energy.
Fats and oil are composed of?
composed of three fatty acid molecules and one glycerol molecule.(triglycerides,)
What is glycerol?
its a three-carbon molecule with three hydroxyl (—OH) groups, one for each carbon.
What are fatty acids?
They are long chains of hydrocarbons with a carboxyl group (—COOH) at one end.
What is the bond made between glycerol and fatty acids molecules?
ester linkages
What are saturated fatty acids?
they have only single carbon-to-carbon bonds (i.e., no double bonds) and are said to be saturated with hydrogens.
How do saturated fatty acids look at room temperature?
rigid and straight, and solid
What are unsaturated fatty acids?
they have at least one double-bonded carbon in one of the chains —the chain is not completely saturated with hydrogen atoms.
What does it mean for something to be monounsaturated?
one double bond
What does it mean for something to be polyunsaturated?
more than one double bond
The double bonds in unsaturated fatty acids cause what?
kinks” that prevent easy packing.
Since double bonds prevent easy packing how are unsaturated fatty acids at room temperature?
liquid
What are phospholipids? (What do they have?)
they have two hydrophobic fatty acid tails and one hydrophilic phosphate group attached to the glycerol.
How does phospholipids orient themselves in water?
the phosphate group faces water and the tail faces away.
phospholipids have a hydrophobic and hydrophilic ends what can it be called ?
amphipathic
In a aqueous environment these lipids form what?
bilayers,
What are Carotenoids & Chlorophylls ?
These are light-absorbing pigments found mostly in plants.
The b-carotene is a plant pigment used to what?
to trap light in photosynthesis.
In animals, The b-carotene can be what?
broken into two molecules of vitamin A.
What are steroids?
they are signaling molecules/hormones. they are organic compounds with a series of fused rings.
What steroid is a common part of animal cell membranes?
steroid cholesterol
Cholesterol is an initial substrate for what?
synthesis of the hormones testosterone and estrogen.
What are vitamins?
small organic molecules essential to health, not synthesized by the body, so must be acquired from diet.
Some lipids can be what?
vitamins
What are the lipid-soluble vitamins? (Name them)
A, D, E, and K.
What vitamins are water-soluble?
All others (B’s and C)
What are waxes? (cellular wise)
they are highly nonpolar molecules consisting of saturated long fatty acids bonded to long fatty alcohols via an ester linkage.
What differs a fatty alcohol from a fatty acid?
the last carbon, which has an —OH group instead of a —COOH group.
Waxy coating repels and prevent what?
water/water loss from structures
What are the most known nucleic acids?
DNA— (deoxyribonucleic acid) and RNA—(ribonucleic acid)
What are called the monomers of nucleic acids?
nucleotides.
Nucleotides consist of what? (Their components)
a pentose sugar, a phosphate
group, and a nitrogen-containing base.
What are the sugars are in the RNA and DNA?
ribose and deoxyribose
The backbone of RNA and DNA consists of …?
the sugars and phosphate groups,
In the backbone of RNA and DNA by what bond the sugar an phosphate group linked?
phosphodiester linkages
What are the DNA bases and their pairing?
adenine (A), cytosine (C), guanine (G), and thymine (T)///A—T, C—G
What is DNA primary structure?
The sequence of bases is DNA
Purines pair with pyramidines by H- bond what are the purines and pyramidines in the DNA sequence?
Purines: A and G
pyrimidines: C and T
Do the strands of DNA run on the same direction or opposite?
opposite (anti- parallel).
What is the DNA secondary structure?
The two strands of a DNA molecule form a double helix.
What are the bases for RNA and their pairing?
adenine (A), cytosine (C), guanine (G), and uracil (U)/// A—U, C—G
Is RNA single- stranded or double-stranded?
single- stranded
Some RNA complementary base pairing occurs where?
within the structure of some types of RNA.
What is the replicator first hypothesis?
▪ Nucleotides formed polymers; some had the right
shape to be catalytic and reproduce themselves.
▪ DNA does not have this property;
What are ribozymes?
they are folded RNA molecules that can catalyze reactions on their own nucleotides as well as other molecules.
What is DNA?
is an information molecule. The information is stored in the order of the four different bases.
The order of the four different bases is transferred to ….. which is then used to direct ……. in ….?
RNA molecules///the order of the amino acids//proteins.
Is it true that Closely related living species have DNA base sequences that are more similar than distantly related species?
its true
What is humans closest living relative and to how much %?
chimpanzees//98%
Mitochondria & chloroplasts contains what? (In common)
contain their own DNA and their own 70S ribosomes, and can, therefore, make some of their own proteins
What does the endosymbiosis theory state?
Mitochondria & chloroplasts originated when large prokaryotes engulfed but did not digest, smaller ones (what are now known as mitochondria & chloroplasts).
The mutual benefit of Mitochondria & chloroplasts permitted what?
this symbiotic relationship to evolve into eukaryotic organelles of today.
What are peroxisomes?
they are single-membrane-bound organelles involved in oxidation of fatty acids, as well as detoxification of peroxides.
Plant cells & alga cell have vacuole. What is the vacuole?
single-membrane-bound compartment of water, dissolved substances, and digestive enzymes.
What does the cytoskeleton provides?
provides shape, strength, and movement.
There are three types of protein fibre what are they?
Microfilaments,Intermediate filaments and Microtubules
How are microfilament formed and what does it do?
they are formed of the protein actin. Microfilaments strengthen cellular structures & provide movement in animal cytokinesis, in cytoplasmic streaming, and in pseudopod extension.
How are Intermediate filaments formed and what does it do?
they are formed of keratin proteins.
▪add strength to cell attachments in multicellular organisms.
How are Microtubules formed and what does it do?
they Microtubules are formed of the protein tubulin.
▪can lengthen & shorten to help move organelles within the cell; push & pull
chromosomes during cell division.
What are made of microtubules in a 9+2 pattern?
Cilia & eukaryotic flagella
Cilia and eukaryotic flagella are anchored to what?
a basal body
What makes the basal body?
microtubules in a “9 triplets” pattern
What is the cilia?
short, usually many present, move with a stiff power stroke.
What is the flagella?
longer, usually one or two present, movement is snake-like.
Where can we find cilia?
- cilia lining the trachea
- cilia of fallopian tubes
- in movements of protists
Where can we find the flagella?
- flagellum of sperm cells
- in movements of protists
What are centrioles?
made up of “9 triplets” of microtubules (structurally identical to basal bodies)
What are centrioles involved in?
they are involved in the formation of the mitotic spindle—to which chromosomes attach during cell division
What is the extracellular matrix?
its anything external to the plasma membrane.
What does the material in the matrix provide?
protection, support, and attachment for cells
in multicellular organisms.
In plants and algae the extracellular matrix consists of?
cell wall made of cellulose (i.e., fiber).
What is the name of the cell wall of fungi?
chitin
Cell walls provide what?
structure, and a means for withstanding high osmotic pressure in aqueous environments.
In animals (humans included) the extracellular matrix consists of?
mainly of the protein collagen, and some different glycoproteins.
Is there a cell wall in animal cells?
no
What does biological membranes consists of?
lipids, proteins, and carbohydrates.
What describes a phospholipid bilayer in which membrane proteins move laterally within the membrane?
fluid mosaic model
What do peripheral protein attach to ?
the surface of the phospholipid bilayer by ionic bonds
What protein are inserted into the phospholipid bilayer?
Integral membrane proteins
What is called an intergral protein that crosse the bilayer completely ?
transmembrane protein.
Why can 2 surfaces of a membrane have different properties?
different phospholipid compositions,
exposed domains of integral membrane proteins, and peripheral membrane proteins.
Carbohydrates attached to proteins or phospholipids project from the external surface of the plasma membrane functions as what?
recognition signals between cells.
