Lecture Exam 1 Flashcards
1
Q
What is a microorganism? What are some examples?
A
- living things too small to be seen without magnification
- ex. bacteria, archaea, protozoa, fungi, helminths, viruses, algae
2
Q
List and describe the main characteristics that define major type of microorganism covered in Chapter 1.
A
3
Q
What makes viruses different from other microorganisms (such as bacteria, etc)? For example, are viruses living and what is the structure of viruses?
A
- viruses are not living organisms
- viruses are acellular and also require a host cell to replicate
4
Q
What are helminths?
A
- multicellular animal parasites that are flat worms and round worms
5
Q
What does it mean to say a microbe is ubiquitous?
A
They can grow anywhere
6
Q
Define genetic engineering.
A
manipulates the genetics of microbes, plants, and animals for the purpose of creating new products and genetically modified organisms
7
Q
Define recombinant DNA technology.
A
makes it possible to transfer genetic material from one organism to another and deliberately alter DNA
8
Q
Define bioremediation
A
use microbes already present or introduced intentionally to restore stability or clean up toxic pollutants
9
Q
The term used to describe a disease-causing microorganism is ____
A
pathogen
10
Q
What is the leading cause of infectious death in the US? What is the leading cause of infectious death in the world?
A
- In the US = influenza and pneumonia
- In the world = lower respiratory infection
11
Q
Define taxonomy
A
the science of classifying living things
12
Q
Define nomenclature
A
the assignment of scientific names to the various taxonomic categories and to individual organisms
13
Q
Define classification
A
the orderly arrangement of organisms into a hierarchy
14
Q
Define identification
A
the process of discovering and recording traits of organisms so they can be placed in an overall taxonomic scheme
15
Q
Who developed the formal system for classifying and naming organisms?
A
Carolus Linnaeus
16
Q
Each organism has two names. The first name is the ____ and the second name is the _____
A
genus and species
17
Q
Carl Woese proposed that organisms may be classified into one of three different domains by analysis of their _____
A
rRNA
18
Q
What are the three domains proposed by Carl Woese?
A
- bacteria
- archaea
- eukarya
19
Q
How are organisms classified and organized into several descending ranks, beginning with the most general and ending with the smallest and most specific?
A
Domain, Kingdom, Phylum (or division), Class, Order, Family, Genus, Species
20
Q
Who was the first to report that living things were composed of little boxes or “cells” from looking at cork?
A
Robert Hooke
21
Q
Who was the first to look at living microorganisms with a microscope?
A
Anton van Leeuwenhoek
22
Q
Compare spontaneous generation and biogenesis. Describe the experiments performed by Redi, Needham, Spallanzi, and Pasteur. For each experiment, describe if the experiment was in support of spontaneous generation or biogenesis.
A
23
Q
What is pasteurization?
A
the application of a gentle heat for a short time that kills most bacteria
24
Q
What are Koch’s postulates used for? What are the steps for Koch’s postulates?
A
- they are a series of logical steps that establish whether or not an organism is pathogenic and which disease it caused
1) some pathogen must be present in every case of disease
2) pathogen must be isolated from the diseased host and grown in pure culture
3) pathogen from pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal
4) pathogen must be isolated from the inoculated animal and must be shown to be the original organism
25
How did Jenner produce the 1st vaccine?
Jenner exposed an individual to material from cowpox lesion and then exposed them to smallpox with no infection
26
What type of enzymes were discovered in the 1970s that is used to cut DNA in specific ways?
restrictive enzymes
27
What technique was invented in the 1980s by Kary Mullis, that was awarded the nobel prize in 1993, that is used to amplify and subsequently analyze DNA?
the polymerase chain reaction (PCR) technique
28
What is the term for anything that has mass and takes up space?
matter
29
Know the parts of the atom. Name the charge of each part. Which parts are in the nucleus of the atom? Which part of the atom is involved in chemical bonding?
- Protons and neutrons are found in the nucleus
- the electron is involved in chemical bonding
30
What are elements? What defines an element?
- any substance that cannot be reduced to any simpler set of constituent substances through chemical means
= each element is defined by the number of protons in the nucleus
31
Fluorine has 9 protons, 9 neutrons, and 9 electrons. What is fluorine's atomic number? What is fluorine's mass number?
the atomic number is 9 and the mass number is 18
32
What are isotopes? What is it about carbon-12, carbon 13, and carbon 14 that makes them all carbon? What is different between carbon 14 and carbon 12?
- isotopes are variations in mass number in which they have the same number of protons and electrons but different number of neutrons.
- they're all carbon in that they all have 6 protons
- C14 is unstable in that it has 8 neutrons instead of the 6 C12 has
33
How many electrons are in the first electron shell? How many electrons are in second electron shell? How many in the third? When is an atom stable?
First = 2
Second = 8
Third = 8
An atom is stable when it has a filled outer shell
34
What are ions? How do you know if an atom is an ion (what is different in the atom)?
ions are atoms or molecules with an electrical charge resulting from gain or loss of electrons
- there will be a net electrical charge depending on whether or not the atom gained or lost electrons
35
List and describe the three types of chemical bonds
covalent bonds: atoms share one or more bonds
ionic bonds: atoms lose and accept electrons from each other
hydrogen bonds: a covalently linked hydrogen atom can react with an electronegative atom (like oxygen)
36
What is a compound and what is a molecule?
compound: substance consisting of two or more different elements combined in a fixed ratio
molecule: a group of atoms bonded together, it is representative of the smallest chemical compound that can exist through chemical reactions
37
Is a NH3 molecule polar or nonpolar? How do you know? How about a CH4 molecule?
NH3 is polar as there is an uneven distribution of electrons being shared
CH4 is nonpolar as there is an equal distribution of electrons being shared
38
Why does sodium and chloride form a bond?
Sodium and chloride form an ionic bond as their electronegative differ to the extreme in which Cl can completely take the one electron resting in the outer shell of the Na to fill its outermost shell
39
What atoms do organic molecules always contain? What atom do inorganic molecules usually lack?
Organic compounds always contain carbon and hydrogen
Inorganic compounds typically lack carbon
40
Why is water considered to be polar? In hydrogen bonding, what will the hydrogen of one water molecule bond with?
Water has electrons that are not distributed equally, making it polar.
It will bond to the oxygen of another water molecule
41
What property of water allows water to be transported up a plant from the roots to the leaves?
cohesion
42
Water has a great capacity to absorb and retain heat. Because of this, we say that water has a high _____
specific heat
43
What property of water allows life to live in water even when the water freezes in colder climate?
the crystalline structure of ice allows the surface of water to freeze at the surface but remains liquid underneath
44
What is a solution, a solute, and a solvent?
a solution is a completely homogenous mixture made of two or more substances.
a solute is a substance that is dissolved
a solvent is substance in which something is dissolved
45
When you add a salt to water and the salt dissolves, what is the salt called?
salt would be the solute
46
What makes a compound hydrophobic or hydrophilic?
- a compound is hydrophilic in that it has an affinity to water, and it can make hydrogen bonds with water
- hydrophobic is when it is excluded (repelled) by water, or it can't make hydrogen bonds with water
- hydrophilic: ionic compounds, polar molecules
- hydrophobic: nonionic, nonpolar
47
What is an acid and what is a base? What is an example of each?
- an acid is a substance that releases H+ in solution and increases H+ concentration (ex. HCl)
- bases release OH- and decrease H+ concentration (ex. NaOH)
48
If an acid is added to water, will the pH of the solution increase or decrease? Why?
It will decrease the pH as H+ concentration increases
49
If a base is added to water, will the pH of the solution increase or decrease? Also, what happens to the hydroxide ion concentration as a result of a base being added?
It will increase the pH as H+ concentration decreases.
- the hydroxide ion concentration increases
50
What is a buffer? How does it work (i.e what happens when H+ is depleted or in excess)?
A buffer helps substance resist change in pH.
- it donates H+ when depleted and accepts H+ when in excess
51
Why is carbon central to life (i.e what is it about its structure that makes it important?)
it has an outer shell of only four of the eight electrons necessary for maximum stability in most elements.
- carbon atoms are able to form stable, covalent atoms with a wide variety of atoms
52
What are functional groups and why are they important?
a group of atoms that confer a special property on a carbon-based molecule
- this affects a biological molecule's function in a characteristic way
53
What are the four classes of macromolecules? List the necessary atoms that must be present within each of them.
carbohydrates: carbon, hydrogen, and oxygen
lipids: carbon, hydrogen, and oxygen (sometimes nitrogen, phosphorous, and sulfur)
proteins: carbon, hydrogen, oxygen, nitrogen (sometimes sulfur)
nucleic acids: carbon, hydrogen, oxygen, nitrogen, phosphorous
54
What type of reaction takes place when monomers are linked together to form polymers? What type of reaction takes place when polymers are broken down? What happens in each reaction?
- when monomers are linked together to form polymers, this is an example of a dehydration reaction, when monomer attaches to growing chain- resulting in loss of 1 water molecule
- the disassembly of polymers is hydrolysis, when one monomer breaks off the end of the polymer- this requires 1 water molecule
55
What is the monomer and polymer of carbohydrate?
monomer: monosaccharide
polymer: polysaccharide
56
What is the monomer and polymer of protein?
monomer: amino acid
polymer: polypeptide/protein
57
What is the monomer and polymer of nucleic acid?
monomer: nucleotide
polymer: nucleic acid
58
What are the four complex carbohydrates that are important in life? What is the function for each?
starch: nutrient storage form of carbohydrates in plants
glycogen: nutrient storage form of carbohydrates in animals
cellulose: rigid, structural carbohydrate found in cell walls of many organisms
chitin: tough carbohydrate that form external skeleton of arthropods
59
What is the structure of a fat? Is a fatty acid polar or non-polar? Why?
they contain 1 glycerol molecule and 3 fatty acid molecules
fatty acids are nonpolar due to their hydrocarbon chains, they are hydrophobic
60
What is the difference between saturated and unsaturated fats? Which is more likely to be solid at room temperature? Why?
-saturated fats have all single carbon-carbon bonds and molecule is saturated with hydrogen
- unsaturated fats have at least one carbon-carbon double bond meaning it is not fully saturated with hydrogen
saturated fats are more likely to be solid at room temp because the molecules easily stack together
61
What class of macromolecules do steroids belong to? What class of macromolecules do phospholipids belong to?
they both belong to lipids
62
Describe how phospholipids orient themselves to form cell membranes (i.e what part of the phospholipid interacts with the inside of the cell, etc)
since they are amphipathic, the polar/hydrophilic bond is facing outward, interacting with water, while the nonpolar/hydrophobic tail is facing inward
63
What is different between one amino acid and another? In other words, which part of the amino acid is variable?
they differ in their R group as each R group has a specific shape and chemical property
64
Describe the four levels of structure of proteins
primary: determined by amino acid sequence
secondary: coiling and pleating of chain held by hydrogen bonds
tertiary: irregular folding due to bonding between the R-groups of AA's in the polypeptide chain
quaternary: interaction between two or more polypeptide chains
65
Why is a fever so bad for our body?
When body temperatures rise, proteins in our body denature above 104 degrees F
66
Which monomer composed of a sugar, phosphate group, and a nitrogenous base?
nucleotides
67
Compare and contrast DNA and RNA (i.e what is the same and what is different)
refer to chart in study guide
68
What structures are found in ALL cells?
1) cell (plasma) membrane
2) chromosomes
3) ribosomes
4) cytoplasm
69
What are the differences between prokaryotic and eukaryotic cells?
prokaryotic:
- one (or few) circular chromosomes, not in a membrane
- no histones
- no membrane-bound organelles
- peptidoglycan cell wall if bacteria
- pseudomurein cell wall if archaea
eukaryotic:
- paired, lined chromosomes
- histones
- membrane-bound organelles
- polysaccharide cell walls
- mitotic spindle
70
What is the approximate size of a bacterium?
1 micron
71
Are most bacteria monomorphic or pleomorphic? What do those two terms mean?
most are monomorphic
monomorphic: they have one shape
pleomorphic: they have more than one shape
72
Describe each of the following shapes of bacteria (morphology): bacillus, coccus, vibrio, spirillum, and spirochete
bacillus (bacilli plural): have a rod shape in appearance
coccus (cocci): spherical or oval in shape
vibrio: have a curved rod shape that looks like a comma
spirillum (spirilla): have a rigid-spiral form
spirochete: have a flexible spiral shape that looks like a corkscrew
73
What is the difference between bacillus and Bacillus (italics)
Bacillus (italics) is the scientific name whereas bacillus is the shape
74
Describe each of the following bacterial arrangements: diplo-. strepto-. and staphylo-
diplo: is in reference to a paired arrangement
staphylo: looks like clusters
strepto: has a chained appearance
75
What is the glycocalyx in prokaryotic cells and what is it made of?
a gelatinous external layer made of polysaccharide or polypeptide
76
What are the two types of glycocalyx and how do they differ?
slime layer: loosely organized and attached
capsule: highly organized, tightly attached
77
Explain what a capsule is. what it's made of, and the advantages it confers to bacteria, Name at least one capsule producing organism (genus and species) and the disease it causes.
it is highly organized type of glycocalyx made up of mucoid polysaccharide or polypeptide
- it prevents dehydration/nutrient loss, adds adherence factor, protects from phagocytosis, and adds virulence factor
Bacillus anthracis: causes anthrax
78
When growing in an animal, Bacillus anthracis produces a capsule that is resistant to phagocytosis. The capsule is composed of the amino acid D-glutamic acid. Why is this capsule resistant to digestion by the host's phagocytes?
since made of D-glutamic acid, its D isoform is a less common amino acid that can't be digested by the immune system
79
What are biofilms?
They are microbial communities that form slime or hydrogels
80
What advantage do the pillar-like structures give bacteria in a biofilm?
they allow bacteria to receive more oxygen and nutrient
81
What are common sites that the biofilms are found?
teeth. mucus membrane, heart valves, catheters, implants, and organ transplant
82
What advantages do a biofilm give to a bacterium?
they allow bacteria to share nutrients, they are sheltered from harmful factors in the environment (desiccation, antibiotics, and body's immune system) and help with conjugation (transfer of DNA)
83
What are the three parts to the prokaryotic flagellum and what does each part do?
Filament: contains globular protein flagellin arranged is several chains that intertwine and form a helix around a hollow cone
Hook: moves to help move flagella
Basal body: anchors the flagellum to the cell wall and plasma membrane
84
How does the basal body of flagellum vary for Gram (+) bacteria compared to Gram (-) bacteria?
gram (+): have a thick layer of peptidoglycan on the outside
gram (-): bacteria have a thin layer of peptidoglycan and an outer membrane
85
What are the different arrangements of bacteria flagellum?
monotrichous: one at one end
lophotrichous: more than one at one end
amphitrichous: tuft at both ends
peritrichous: over entire cell
86
What is chemotaxis and what is phototaxis?
chemotaxis: is the movement toward a chemical stimuli
phototaxis: is the movement toward a light stimuli
87
What is the difference between positive chemotaxis and negative chemotaxis?
positive chemotaxis: movement towards stimuli
negative chemotaxis: movement away from stimuli
88
What are H antigens and why are they useful?
they are flagella proteins that are useful to determine strains of bacteria
89
What are axial filaments used for? How do they work? What type of organisms have axial filaments?
axial filaments: anchored at one end of a cell and cause cell to rotate similar to a corkscrew
- they are found in spirochetes
90
What are the fine, proteinaceous hair-like bristles on the surface of a bacterial cell, that are used for adhesion to surfaces and other cells called?
fimbriae
91
What are pili and what cell types have them? What are they used for?
they are rigid tubular structures made of pilin protein
- they are found in gram negative cells
used to:
1) transfer genetic material (conjugation)
2) act like fimbriae and assist in attachment
3) act like flagella and make a bacterium motile
92
What types of genes can be transferred during conjugation?
New genes for antibiotic resistance, capsule/fimbriae/pili production
93
Describe the two types of DNA sequences that can be found in the nucleoid region in prokaryotic cells.
Bacterial chromosomes: one circular, double-stranded chromosome
Plasmids: extra chromosomal genetic elements; carry non-crucial genes (antibiotic resistance, production of toxins)
94
Describe the structure and function of ribosomes.
They are composed of rRNA and proteins to synthesize proteins. There is one large subunit and one small subunit.
95
How are prokaryotic ribosomes different than eukaryotic ribosomes?
eukaryotic cells: the small subunit is 40S and large is 60S, combined is 80S
prokaryotic cells: small sub unit is 30S, large is 50S, and combined is 70S
96
What are inclusions?
Intracellular storage bodies that serve as temporary reserve deposits
97
Explain what an endospore is, what it's made of, and what it's functions.
structures that are used to survive adverse environments
- they package DNA into endospore structures made of keratin protein in harsh conditions like dehydration, lack of nutrients, radiation, temperature, chemicals, etc
98
Name the medically important bacteria that form endospores and list the disease they cause. Which genus tend to live in anaerobic environments?
Clostridium: anaerobic
Bacillus: aerobic
Clostridium tetani - causes tetanus
Bacillus anthracis - causes anthrax
99
What is the function of the bacterial cell wall? What is it made primarily of in most bacteria?
- prevents osmotic lysis and protects the cell membrane.
- It is primarily made of peptidoglycan
100
Describe the structure of peptidoglycan
it is a polymer of disaccharide
- consists of rows of carbohydrates linked by polypeptides
101
What does the gram negative outer membrane protect the bacteria from?
phagocytes, complement antibiotics, digestive enzyme, detergents, etc
102
What are the components for the lipopolysaccharides (LPS) in the outer cell membrane of Gram negative bacteria? What is each used for?
O polysaccharide: functions as antigen
Core polysaccharides: is there structurally to provide stability
Lipid A: endotoxin embedded in the top layer
103
Why is it important for a physician to know if an infection is caused by a gram negative or a gram positive bacterium.
It is a practical aid in diagnosing infection and guiding drug treatment.
- due to their cell wall, gram + bacteria are generally more susceptible to certain antibiotics that target the cell wall, while gram - bacteria are more resistant due to their outer membranes
104
List the 4 steps of the gram stain and explain how each step works during the staining process. What will gram + and gram - cells look like at the end of each step? Explain why gram + cells stain differently from gram - cells
1) Primary stain with crystal violet, coloring both gram + and gram - purple
2) Mordant with iodine that creates a CV iodine complex with the cell wall of the gram + bacteria, allowing dye to be trapped in cell. Has no effect on gram negative cell
3) Decolorize with alcohol, the CV will remain in the gram + bacteria due to the complex, but the outer membrane of the gram - cell will become weak and lose the dye
4) Counterstain with safranin, since it's a lighter pink dye, the gram + will remain its dark purple while the gram -, originally colorless, will dye pink
105
Explain why Mycobacterium is medically-important, how its cell wall is unique, and any advantages this bacterium has towards survival in the external environment and inside the human body. Name one genus and species of Mycobacterium and the disease it causes.
Mycobacterium is an atypical acid-fast cell wall.
- its made up of 60% mycolic acid and is resistant to chemicals (antibiotics, disinfectants) and resists dehydration, phagocytic digestion and chemicals
Mycobacterium tuberculosis: causes tuberculosis
106
Describe the cell wall (or lack of) for Mycoplasma pneumoniae. What does it use in the cell membrane to protect against lysis?
Since they lack a cell wall, they are pleomorphic, or can take on many shapes
- it uses sterols
107
What are two types of chemicals that damage the cell wall? Do those chemicals affect gram negative or gram positive bacteria more?
lysozyme: digest disaccharide in peptidoglycan
penicillin: inhibits peptide bridges in peptidoglycan
affects gram + more
108
Describe the structure of the phospholipid bilayer. What causes it to orient in the way that it does?
Phospholipid bilayer consists of a double layer of phospholipids that have a hydrophilic head, and hydrophobic tail. The head faces outward and the tail faces inward.
- allows hydrophobic molecules to pass through freely allowing for permeability of the bilayer
109
What are the functions of the cell membrane in bacteria?
site for energy reactions (ATP), nutrient processing, transport into and out of cell
110
True or false. The cell membrane functions to provide cell support and structure. Explain your answer.
True. It does in the sense of the fluid mosaic model where membrane is flexible enough to allow cell to adapt in shape and move in various environments
111
True or false. One of the functions of the cell membrane is to produce ATP for energy. Explain.
True. The cell membrane is the site of ATP production in bacteria due to a lack of mitochondria
112
What does the fluid mosaic model state? Is the membrane a fluid structure or a rigid one?
The membrane is a fluid structure that is as viscous as olive oil, allowing proteins to move freely
113
Name the 4 components of the plasma membrane in Eukaryotic cells and list the function of each.
Phospholipid bilayer: structure of hydrophilic heads and hydrophobic tails
Cholesterol: act a patching substance that help cell maintain an optimal level of fluidity
Proteins: various functions (transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and extracellular matrix
Glycocalyx: serve as protein binding sites and as cell lubrication and adhesion molecules
114
What part of a phospholipid is hydrophobic? What part is hydrophilic?
hydrophobic: tail
hydrophilic: head
115
Compare and contrast the cell membrane in prokaryotic cells and in eukaryotic cells
Similar: they both have phospholipid bilayers and integral and peripheral proteins
Different: most eukaryotic cells use sterols embedded in membrane to maintain fluidity. They also use carbohydrates for attachment and cell-cell recognition
116
What type of molecules can pass through the phospholipid bilayer? What types of molecules cannot pass?
hydrophobic molecules pass through
hydrophilic molecules cannot pass through
117
In diffusion, do molecules move up or down their concentration gradient? What does it mean when something moves down its concentration gradient?
They move down their concentration gradient, meaning they go from region of higher concentration to a lower concentration
118
What is the difference between a solution that is hypertonic, hypotonic, or isotonic? Know which direction water will move if a cell is placed into each solution.
Hypertonic: higher solute concentration - water moves out of cell
Hypotonic: lower solute concentration - water moves into cell
Isotonic: equal solute concentration on both sides of membrane - no movement of water
119
If you see a cell in which water is moving into the cell, is the solute concentration outside the cell higher or lower than the solute concentration inside the cell? Was the solution hypotonic, isotonic, or hypertonic?
solute concentration is lower outside the cell and is hypotonic
120
What is required for a substance to move passively across a cell membrane?
they need to move down concentration gradient
121
Describe the types of passive transport and indicate which types of molecules or ions move by each way
1) No energy required
- simple diffusion: limited to small and hydrophobic molecules
2) Facilitated diffusion (transport protein required)
- channel protein: for ions and polar molecules to pass
- carrier protein
122
Does active diffusion, passive diffusion, or both, require the energy from ATP?
passive diffusion requires no ATP. Active does
123
If you wanted to move something against its concentration gradient, which type of transport would you need to move it against the gradient?
ion pumps or co-transporters
124
Describe the two types of active transport
1) ion pumps: like protein pumps or sodium potassium pumps
2) co-transporters: require two transmembrane proteins
- one to pump a molecule up its gradient and onto let molecule flow down gradient
125
What is the difference between endocytosis and exocytosis?
exocytosis: how cell secretes material
endocytosis: how cell takes in material
126
What are the three types of endocytosis? How are they different?
phagocytosis: particles engulfed by extensions of membrane
pinocytosis: liquid with dissolved solutes is taken in
- pockets form that take in liquid (no extensions)
receptor mediated: cell takes in large amounts of specific substance
- receptors on cell surface in coated pits
- coated pits form coated vesicles that are taken into cell
127
What organelles are found in animal cells, but not in plant cells? What organelles are found in plant cells, but not in animal cells?
In animal cells but not in plant cells: lysosomes, centrioles, flagella (in some plant sperm)
In plant cells: chloroplasts, central vacuole, cell wall, plasmodesmoid
128
What is the name for membrane enclosed structures in the cell that can compartmentalize a cell's activity?
organelles
129
What is transcription and where does it take place in a eukaryotic cell? What is translation and where does it take place in eukaryotic cells?
Transcription: DNA-dependent RNA synthesis, RNA is exported for nucleus
- takes place in nucleus
Translation: RNA-dependent protein synthesis
- takes place in cytoplasm
130
What is the function of the nucleolus?
Site of ribosomal RNA synthesis and ribosome activity
131
What organisms and/or organelles can 70S ribosomes be found?
prokaryotic cells, chloroplasts, and mitochondria
132
Information is transferred from the nucleus to ribosomes via ____ (what molecule)
mRNA
133
Describe the structure of the eukaryotic ribosome
They are 80S ribosomes in weight that can be found in cytosol
- they are composed of rRNA made in nucleus combined with proteins made in cytosol
- made up of two subunits
134
If you see a cell that synthesizes a lot of protein, what structure will that cell have a lot of that allows it to synthesize proteins?
more ribosomes
134
What structure in the cell is responsible for synthesizing the membrane?
rough endoplasmic reticulum
135
Describe how proteins are made from DNA.
1) Nucleus: site of DNA storage and transcription
2) Ribosomes: protein synthesis, where mRNA is read and proteins are assembled
3) Rough endoplasmic reticulum: ribosomes attached to ER synthesize proteins that are destined for secretion or for incorporation into membranes
4) Golgi apparatus: modifies, sorts, and packages proteins for transport to their final destination
136
What is the function of the smooth endoplasmic reticulum? What cell type in the human body have a high proportion of smooth ER?
- synthesis of lipids
- metabolism of carbohydrates
- detoxification of drugs and proteins
- calcium sequestration
- liver cells
137
What structure would you expect to be abundant in the liver cells of an alcoholic? Why?
Smooth ER, due to the liver's modification of toxic substances
138
What is the function of the lysosome?
responsible for digestion (fuses with vacuoles to digest food)
also recycles damaged organelles
fuses with phagosomes to destroy foreign invaders
139
Tay Sachs disease results from the malfunction of which organelle?
missing an enzyme in lysosomes that break down lipids
140
What is the function of the central vacuole in plants?
- stores organic materials, such as proteins in seeds
- contributes to plant growth by absorbing water and causing cells to expand
- in flower petals contain pigment to attract pollinating insects
- may contain poison to protect against plant-eating animals
141
List the functions for the following organelles: mitochondria and chloroplast
Mitochondria: site of cellular respiration
- extracting energy from organic molecules
- produces ATP
Chloroplast: site of photosynthesis
- synthesizing of organic molecules using solar energy
- produces glucose that can be used to produce ATP
142
Describe the structure of mitochondria and chloroplasts
Mitochondria:
- surrounded by two lipid bilayer membrane (smooth other membrane and extensively folded inner membrane, cristae)
- creates two compartments (intermembrane space and matrix)
Chloroplasts:
- 3 spaces
- intermembrane space (space between inner and out membrane)
- stroma (inner membrane space)
- thylakoid (inner thylakoid membranes)
143
What two organelles are believed to be remnants of unicellular bacteria?
mitochondria and chloroplasts
144
What is the name of the theory that states that mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells
endosymbiont theory
145
What do mitochondria and chloroplasts have in common with bacteria that supports the endosymbiotic theory?
- circular DNA (like bacteria) - similar sequences too
- 70S ribosomes (like bacteria)
- Self-replicating (like bacteria)
- same size as bacteria (1 micron vs 2 micron)
- 16S rRNA (like bacteria)
146
What are the three types of cytoskeletal elements and what are the functions for each one?
Microfilaments
- cell shape (structural support)
- Muscle contraction
- cleavage furrow for cell division
- amoeboid movement: cell movement and capture prey by forming rapidly
Intermediate filaments
- maintenance of cell shape and stabilizing of the position of the nucleus and organelles within the cell
Microtubules
- cell shape
- movement of vesicles, chromosome, and organelles
- cell mobility
147
What proteins are microfilaments made of? What protein are microtubules made of?
microfilaments: actin
microtubules: tubulin
148
What cytoskeleton element makes up cilia and flagella?
both consist of microtubules made of tubulin protein
149
What is the difference between flagella and cilia in eukaryotic cells?
flagella
- longer and fewer in number
- used for cell movement or moving the cell through fluid
cilia
- shorter and more numerous
- used for moving fluids or material across cell surface
150
What are the differences between eukaryotic and prokaryotic flagella?
- eukaryotic flagella covered by an extension of the cell membrane and is 10x thicker than in prokaryotes
- flagella movement is undulating (wave-like) for eukaryotes, but rotates circular in bacteria
- eukaryotic flagella is made of tubulin and prokaryotic is made of flagellin
151
What is the function of glycocalyx in eukaryotic cells? What is it made of?
- contribute to protection, adherence, and signal reception
- made of polysaccharides
152
Describe the structure of the fungal cell wall
- rigid and provide structural support and shape
- different in chemical composition from bacterial and archaeal cell walls
- thick inner layer of polysaccharide fibers composed of chitin or cellulose
- thin outer layer of mixed glycans
153
What is the purpose of sterols in the membrane of eukaryotic cells?
- relative rigidity give stability to the membrane
- important in cells that do not have a cell wall
