Card Set Information
What do all cells come from?
What are the 3 domains of life?
Bacteria, Archea, Eukarya
What are the 2 types of Prokaryotes?
What are the 3 properties of all cells?
Compartmentalization and metabolism, Growth, Evolution
What does evolution result in?
What are 3 properties of some cells?
Motility, Differentiation, Communication
How do most cells communicate?
Many cells communicate or interact by means of chemicals that are released or taken up.
What is metabolism?
Generation of precursors of macromolecules
Which is bigger, eukaryotic cells or bacteria?
Eukaryotic cells are much bigger than bacteria?
Why is there an upper limit on the size of cells?
As size increases, the surface: volume ratio decreases and if the surface is not big enough, it will not be able to exchange with the outside- not enough nutrients
Why is there a lower limit on the size of cells?
Because its needs to grow and replicate
What is the main difference between prokaryotes and eukaryotes?
Prokaryotes have a nucleus and nucleolus
Where is DNA kept in eukaryotes?
DNA is in the cytoplasm and packaged in the nucleoid
What is the nucleoid?
A grouping of DNA, not surrounded by a membrane
Where are ribosomes located?
Can be in the cytoplasm, or attached to the endoplasmic reticulum
What direction does active transport go in?
Active transport goes against the gradient
What is an integral membrane protein?
A membrane protein that spans the entire membrane
What is the purpose of the cytoplasmic membrane?
Stops things from coming in and out, it is the reason that the inside of the cell an remain different from the outside
What are porins?
Transport by diffusion, and differentiate only by the size of the substrate
What are the 3 purposes of the cytoplasmic membrane?
Permeability barrier, Protein anchor, Energy conservation
Does the phospholipid bilayer require energy to make?
No, the phospholipids naturally arrange themselves into a bilayer
What type of linkage do bacteria and eukarya use to link fatty acids to the glycerol backbone in the phospholipid bilayer?
What type of linkage do archea used to link isoprene to the glycerol backbone in the phospholipid bilayer?
What is the main difference between Bacteria/eukarya and archea with reference to the phospholipid bilayer?
Bacteria/Eukarya= Ester linkage and fatty acids, Archea= Ether linkage and isoprene
Do any bacteria have monolayers?
What substance is linked to the glycerol backbone in archea?
Isoprene via an ether linkage
Which species can form a lipid monolayer?
Why can archea form a lipid monolayer?
Isoprene tails can attach to each other, whereas fatty acids cannot
Do archea always have lipid monolayers?
No, they could also have lipid bilayers
How is the lipid bilayer stabilized in eukaryotes?
Stabilized by sterol
How is the lipid bilayer stabilized in prokaryotes?
What sterol is found in animals?
Do prokaryotes have a nucleus?
No, the genetic information is stored in the nucleoid, which has no membrane
What is a ribosome composed of?
Composed of ribosomal RNA and proteins
What do ribosomes do?
Translate mRNA into amino acid chains to form proteins
Why are prokaryote and eukaryote ribosomes so different in size?
Because they are formed of different proteins and different RNA
Which ribosomes are bigger, prokaryote ribosomes, or eukaryote?
Eukaryote ribosomes are much bigger because they are made of more proteins
How do we measure the size of ribosomes?
What is a Svedburg unit?
Describes the rate of sedimentation of a particle in an ultracentrifuge.
What is the number of svedburg units proportional to?
Size, shape and density?
Do Svedburg units follow a linear relationship?
How does ultracentrifugation work?
Precipitate small molecules, molecules migrate in solution based on density, size and shape
How much force does an ultracentrifuge use?
Up to 100 000 gravities
What gives cells structure?
Microtubules, microfilaments, and actin
What is a golgi complex responsible for?
Distribution of proteins
What are transcription factors?
Proteins that dictate which genes will be expressed
How many lipid bilayers does the nucleus of eukaryotes have?
2 bilayers (double membrane)
Is RNA translated in the nucleus?
No, transcription occurs inside the nucleus, but the RNA must be transported outside in order for translation to occur
What are the 2 types of chromatin in eukaryotes?
What is Euchromatin?
Loosely packed, actively transcribed
What is heterochromatin?
Densely packed, low level of transcription
What is the purpose of histoproteins?
Why is heterochromatin not actively transcribed?
It is very densely packed and the polymerase cannot get to it
What types of cells have a cell wall?
Cells of plants, algae, fungi- Cell walls are absent in animal cells and most protozoa
What is the purpose of a cell wall?
Forms a tough, rigid barrier that helps protect the cell and gives it shape
What is the cell wall of eukaryotes usually composed of?
What substance is the cell wall of plants, most algae and some fungi usually composed of?
What substance is the cell wall of fungi composed of?
What is the membrane of the endoplasmic reticulum composed of?
What is the different between the rough ER and the smooth ER?
Rough ER is studded with ribosomes
What is the purpose of the rough ER?
What is the purpose of the smooth ER?
Synthesis of lipids
How is the nucleus attached to the endoplasmic reticulum?
Nucleus shares one membrane with ER
What is the Golgi apparatus?
It is a set of membrane compartments involved in further processing proteins and distribution
How does the Golgi apparatus transport proteins?
Proteins are packaged in vesicles, tagged with their destination and are transported to where they are required
What are lysosomes?
Internal vesicles that contain hydrolytic enzymes required for degradation of materials brought in by phagocytosis and endocytosis
Do all protozoa have mitochondria?
No, only some do
What is the main purpose of mitochondria?
Where most of the ATP is produced
What does the outer membrane of the mitochondria look like?
Contains many porins so the membrane is very permeable to small molecules
What does the inner membrane of the mitochondria look like?
75% proteins, 25% lipids. Contains transport proteins, enzymes, cytochromes, ATPases
What happens in the mitochondrial matrix?
What kind of ribosomes does the mitochondria contain?
What is oxidation?
Removal of electrons
What is reduction?
Addition of electrons
Why must redox reactions occur in pairs?
Because electrons cannot exist in solution
Where are chloroplasts found?
What are thylakoids?
Closed system of interconnecting sacks and tubules
What is a stroma?
Circular DNA, 70s ribosomes, emzymes of the calvin cycle
Do chloroplasts carry their own DNA?
What do thylakoids contain?
Enzymes and pigments that harvest light energy and the membrane-bound ATPases that use the converted energy to produce ATP
What do thylakoids produce from light?
ATP and carbohydrates
How are thylakoids and mitochondria similar?
Both have 70s ribosomes, double membranes, and own circular DNA
What does the cytoskeleton of eukaryotes do?
Gives cell shape, organizes cytoplasm and allows motility
What are the three components of a cytoskeleton?
Microtubules, actin filament, intermediate filament
What are microtubules composed of?
Alpha-tubulin and beta-tubulin
What is actin filament composed of?
What is Intermediate filament composed of?
Keratin, desmin, vimentin
Do prokaryotes also have cytoskeletons?
What is the most important component of the cytoskeleton?
How are microtubules formed?
Alpha and beta tubulins for dimers, which are then organized into a hollow helix-like formation
Where do microtubules grow from?
Grown from the centrosome
Where in the cell are intermediate filaments found?
What do microtubules serve as?
Microtubules serve as highways for the transport of organelles and vesicles around the cytoplasm.
What ‘walks’ along the microtubules?
Kinesin and dynein are two proteins that attach to vesicles or organelles and ‘walk’ on microtubules, transporting their cargo to where they are required
What are microtubules the components of?
Centrioles and centrosomes
What is a 9+0 construction?
A centriole is made of 9 sets of one complete, and 2 partial microtubules
Where are centrioles located within the cell?
Close to the nucleus
What are centrioles called when they are close to the cytoplasmic membrane?
How do microtubules relate to meiosis?
They form the spindles that pull the chromosomes apart
What type of construction do flagella have?
What types of cells contain flagella?
Mostly protozoa- some animal cells
What do flagella and cilia do?
Help cells move
What is the main difference between cilia and flagella in prokaryotes vs eukaryotes?
In eukaryotes, cilia and flagella are covered y cytoplasmic membrane, but are not in prokaryotes
What allows the growth of cilia and flagella?