Chapter Four: Origin and General Features of Cells Flashcards
The Cell Theory (3)
- Cells are the fundamental unit of life
- All organisms are composed of Cells
- All cells come from preexisting cells
As cells increase in volume the surface area also increases, but at a ___________ rate.
lesser
The cell’s ____________ determines its metabolic activity.
volume
The cell’s ________ ________ determines the rate of transport into and out of the cell.
surface area
As a cell grows, its ____________ ____________ increases, but at a rate faster than the increase in surface area.
Metabolic Activity
Magnification makes something ___________
larger
resolution makes something _____________
clearer
Microscopes increase both the ____________ and _____________ of objects
magnification and resolution
The ability to see two objects as two instead of one object
Resolution
What kind of microscope uses light passing through the sample to observe objects?
Light Microscope
200 nm (2 x 10^-4 mm) is the resolving power for what microscope?
Light Microscope
What kind of microscope uses an electron beam passing through the sample to view objects?
Transmission Electron Microscope
What kind of microscope’s resolving power is 0.2 nm (2 x 10^-7 mm)
Transmission Electron Microscope
Cells must be killed and stained with heavy metals to block the electron beam in what microscope?
Transmission Electron Microscope
What microscope coats the surface of the sample with heavy metal stains, then uses an electron beam to scan the surface and obtain more of a 3D view of the surface?
Scanning Electron Microscope
What microscope’s resolution is about 10nm?
Scanning Electron Microscope
Life requires an interaction between what three things?
- DNA
- RNA
- Protein
What are the four proposed stages of the origin of life?
- production of nucleotides and amino acids
- polymerization of these monomers into polymers
- enclosing the polymers in membranes
- membrane-bound photocells acquire cellular properties
What did Oparin and Haldane propose in the 1920s?
Nucleotides and Amino Acids were produced spontaneously under early earth conditions
Oparin and Haldane suggested that monomers were produced and accumulated in what is called a “____________ __________”
Primordial Soup
In the 1950s, geologists suggested the early Earth’s atmosphere was a reducing one consisting of what three molecules?
- Water Vapor
- Hydrogen
- Ammonia
It is important there was no free ___________, since that would destroy any organic molecules produced.
Oxygen
What did Stanley Miller produce in 1953?
An enclosed system which circulated reducing gases in which a spark produced an energy source and produced simple organic molecules
Those who have suggested that Miller is wrong says that the atmosphere is composed mostly of what 5 molecules?
- Carbon Monoxide
- Carbon Dioxide
- Nitrogen
- Sulfur Dioxide
- Water
The mixture of the five atmospheric molecules gives less diversity and __________ yields of amino acids.
lower
UV light would destroy _____________ and _____________, preventing their accumulation in an early atmosphere.
Methane and Ammonia
Other scientists suggest that _____________ could have brought sufficient amounts of organic molecules to Earth.
Meteorites
Other scientists suggest molecules would form at the edge of ________ ______ _______ where super-heated gasses are vented.
Deep Sea Vents
Chemically the ________ Phosphodiester linkage is preferred over the _________ linkage.
5 prime - 2 prime
5 prime - 3 prime
Has Ribose been proven possible under any of the conditions expected in early Earth system?
No
Where does Steve Benner propose RNA is formed and how it comes to Earth?
It was formed on Mars and came to Earth on meteorites
Monomers attach together to form…
Polymers
Hydrolysis would compete with __________________ reactions (polymerization)
Condensation
Water promotes ________________ removal
depurination/base
It is unlikely that ______________ would occur in aqueous environments, but rather on solid surfaces
Polymerization
Many ________ bind Nucleotides and Amino Acids.
clays
__________ can position Nucleotides to connect the phosphate of one with the Ribose of another.
Cations
Cations favor the use of _________ over T and C
A and G
Cations favor _________ over A and G
Inosine
Clays promote ____________ in presence of water
decomposition
A normal peptide bond requires a ___________ to insure correct bond formation
Ribosome
Side chain of _______ ________ can bond to the side chain, amino or carboxyl of another
amino acids
Majority of bonds formed abiotically are NOT _________ _________.
Peptide Bonds
________________ _________ or Phosphate group of one can attach to any of the four hydroxyl groups of Ribose
Nitrogenous Base
If polymers were formed, they would have to be enclosed in _____________ and develop the ability to reproduce
membranes
Organic molecules would need to be __________ from the external environment.
separated
They would eventually need _________ __________ to create new polymers and harness energy
enzymatic functions
If phospholipids are dissolved in water, they form __________
Liposomes
If Liposomes form near ______ it can be incorporated into the Liposome.
RNA
RNA that isn’t incorporated into the Liposome requires ___________ ______________.
protein transporters
_____% of all proteins function in membranes
30
Are membranes made from scratch?
No
All membranes come from ___________ _____________.
preexisting membranes
Favored models of the production of cells propose an “__________ world”
RNA
According to favored models, RNA can do what 3 things?
- function as genetic material
- function as enzymes
- reproduce
the minimum complexity needed to maintain the processes in the simplest cells is defined as…..
Irreducible Complexity
Cells need a minimum of _______ genes
493
DNA replication in simplest prokaryotes requires _____ enzymes and _______ polypeptides
14 and 25
DNA cannot replicate without ________
proteins
proteins cannot be produced without _______ and __________
DNA and RNA
What are the two domains of prokaryotic cells?
Eubacteria and Archaebacteria
Name the three characteristics of Prokaryotic Cells:
- lack membrane-bound organelles
- are relatively simple in structure
- are generally smaller than eukaryotic cells
Name the structure and function of the PLASMA MEMBRANE
single membrane
regulate transport
Name the structure and function of a NUCLEOID
Aqueous
Heredity
Name the structure and function of the CYTOPLASM
Aqueous
Biochemical Reactions
Name the structure and function of RIBOSOMES
Solid - RNA and Proteins
Protein Synthesis
Name the structure and function of the CELL WALL
Peptidoglycan Membrane
Protection/Support
Name the structure and function of a CAPSULE
Polysaccharides
Protection/Hydration
Name the structure and function of the FLAGELLA
Solid - Proteins
Movement
Name the four domains of Eukaryotic Cells
Kingdoms Protista
Plantae
Fungi
Animalia
What are the three characteristics of Eukaryotic Cells?
- possess membrane-bound organelles
- are complex in structure with many organelles
- are larger in size
The Cytoplasm is an aqueous mixture of a wide variety of __________
proteins
The three fibers within the cytoskeleton are constructed from _______ __________
protein monomers
Large, long hollow tubes of Tubulin contributing to the Cytoskeleton
Microtubules
_________ and ___________ _________ control microtubule growth from one point to another
Centrioles and Basal Bodies
Microtubules form cellular “_________” along which vesicles and chromosomes move using molecular “__________” (Kinesin)
roads
motors
Motor proteins are attached to either _______ (cargo) or other cytoskeleton elements
vesicles
Motor proteins have areas that can bind and split _____, and others that move.
ATP
Motor proteins either move vesicles containing various molecules, or other parts of cytoskeleton to create _________ _________ or _____________.
shape changes
movements
Microtubules form ________ and _________ for cellular locomotion
Cilia and Flagella
Microtubules form the _______ ________ for moving chromosomes during cell division
mitotic spindle
What is the structure of Intermediate Filaments
Thin rods of Keratin
________ ____________ are stable elements of the cytoskeleton that are not constantly growing and shrinking
Intermediate Filaments
What is the function of Intermediate Filaments?
Maintain cellular shape and provide mechanical strength to cells
Intermediate Filaments line the inside of the _______ _______ to anchor __________ _______
Nuclear Membrane
Nuclear Pores
What is the structure of microfilaments?
Thin rods of Actin proteins
Microfilaments can exist as ______ ___________, in bundles or in networks
single filaments
What are the five functions of Microfilaments?
- Cellular movements
- Cytoplasmic division
- Support Plasma Membrane
- Anchor Proteins
- Provide Strength and Shape to Cell
Name the structure and function of the NUCLEUS
Double Membrane
Stores DNA
Nuclear Pores _______ __________ between the Nucleus and the Cytoplasm
regulate transport
The Nuclear pores are surrounded by a complex of ___ large protein granules
8
Proteins targeted for the Nucleus have a short peptide ________ __________ __________
Nuclear Localization Signal
Nucleolus: consists of the gene(s) which codes for _____________ ______
Ribosomal RNA
rRNAs are needed for ______________ construction
Ribosome
The outer of the two Nuclear Membranes is in places continuous with the _________ ___________
Endoplasmic Reticulum
What six things are within the Endomembrane System?
- Nuclear Envelope
- Ensoplasmic Reticulum
- Golgi Apparatus
- Lysosomes
- Plasma Membrane
- Vesicles
What is the structure of the Endoplasmic Reticulum?
Single membrane surrounding a central lumen
consists of tubes and flattened sacs
What percent of the cell’s total volume does the ER compose?
10%
It’s membranes, because of the many folds, is many times __________ than the Plasma Membrane
greater
The Rough ER is studded with…
Ribosomes
Ribosomes synthesize _______ which are transported into the lumen of the _________, segregating them from the Cytoplasm
proteins
ER
The proteins in the ER can be ___________ _____________ to alter their functions
chemically modified
Proteins are also “tagged” with a short peptide signal to mark them for _________ to various organelles by vesicles
delivery
Some of these proteins have an oligosaccharides chain attached and form ______________
Glycoproteins
Rough ER _____________ glycoproteins, membrane-bound proteins, and proteins destined for various organelles
Synthesizes
In the Rough ER, ribosomes synthesize proteins which are transported into the lumen of the ER, segregating them from the ______________
Cytoplasm
What organelle lacks ribosomes and is more tubular than flattened sacs; continuous with sections of the Rough ER?
Smooth ER
In the Smooth ER, detoxification of various poisons taken into the body by modifying them to be more ___________ and easier to excrete from the cell
Polar
The Smooth ER contains ______________ needed for Glycogen and Calcium metabolism
Enzymes
The Smooth ER synthesizes ____________ for membranes and other lipids including steroid hormones
Phospholipids
What organelle is made of flattened sacs and has a single membrane surrounding central lumen?
Golgi Apparatus
The Golgi Apparatus adds or modifies ____________ portions of Glycoproteins
Carbohydrate
Proteolysis occurs in what organelle?
Golgi Apparatus
proteases cut proteins into smaller, functional proteins
EX: proinsulin –> insulin
Proteolysis
What organelle concentrates, packages and sorts proteins before being transported to cellular destinations?
Golgi Apparatus
transport proteins from the ER to the cis to medial to the trans regions of the Golgi Apparatus
Vesicles
Large vesicles containing digestive enzymes (Glycoproteins), surrounded by a single membrane
Lysosome
What organelle digests via Hydrolytic Reactions?
Lysosome
Formed by vesicles containing Hydrolytic Enzymes forming form the Golgi
Primary Lysosomes
Formed by the fusion of a primary lysosome and a food vacuole (phagosome)
Secondary Lysosome
Large and small solid subunits composed of 1-3 rRNAs and 20-30 Proteins
Ribosomes
Involved in protein synthesis and is free in the Cytoplasm, attached to the ER, or inside Mitochondria and Chloroplasts
Ribosomes
Similar to large vesicles, they store food or waste materials and maintain turgor pressure
Vacuoles
Freshwater protists use them to excrete excess water. Water diffuses in, then this vacuole contacts, forcing water out of a pore
Contractile Vacuoles
Vesicle-like and contains enzymes for specific functions
Microbodies
These organelles contain catalase that is used to degrade Hydrogen Peroxide (a byproduct in many reactions). They also synthesize as vesicles from the ER.
Peroxisomes
This is a byproduct of many reactions, but in high levels can be toxic. It is degraded by Peroxisomes.
Hydrogen Peroxide
These organelles are like peroxisomes, and contain enzymes for specific reactions, found primarily in plant seeds, and convert stored lipids into carbohydrates for growth
Glyoxysomes
Surrounds the cell and divides it from the external environment
Plasma Membrane
What organelle facilitates membrane transport, facilitates cell signaling, facilitates cell adhesion, and is part of the endomembrane system?
Plasma Membrane
What fills the role of facilitating membrane transport?
Protein transporters
What fills the role of facilitating cell signaling?
Hormones
What fills the role of facilitating cell adhesion?
Different types of proteins
This organelle produces and stores various carotenoid pigments producing red, yellow and orange colors in flowers and fruit
Chromoplasts
What type of organelles are both Mitochondria and Chloroplasts?
Semiautonomous Organelles
What organelle’s responsibility is cellular respiration?
Mitochondria
What organelle’s responsibility is photosynthesis?
Chloroplasts
What two organelles can divide independently of the cell due to containing their own DNA and Ribosomes?
Mitochondria and Chloroplasts
What organelle is double membraned and converts energy in organic molecules to ATP?
Mitochondria
Cellular respiration begins in the Cytoplasm with _________________
Glycolysis
After Glycolysis, cellular respiration continues in the Mitochondria with the _____________ __________ and Electron Transport
Krebs Cycle
What is the end product of Cellular Respiration?
ATP
A modified nucleotide with a high energy content
ATP
If the inner mitochondrial membrane has special pores for protons, the Electron Transport generates _________ instead of ATP
heat
These organelles are chloroplasts and have three membranes
Plastids
Chloroplasts contain the photosynthetic pigments, embedded within internal stacks of membranes called…..
Thylakoids
The fluid surrounding the Thylakoids is the ___________
Stroma
Only 10% of the Thylakoid Membrane is ______________
Phospholipids
These organelles store food (starch and fats)
Leucoplasts
This organelle is a thin mat of cellulose fibers that supports the cell. It limits the volumes of the cell to help maintain Turgor Pressure and forms a barrier to prevent infection by Fungi and Bacteria
Cell Wall
What is the starting point of the Endosymbiont Theory?
Prokaryotic cells - some had Aerobic Respiration and others had Photosynthesis
What is the Engulfment stage in Endosymbiont Theory?
Large Prokaryotic cells engulf smaller ones but do not digest them
According to Endosymbiont Theory, over time these engulfed cells become what two double membrane organelles?
Mitochondria and Chloroplasts
Interwoven mat of Collagen and a matrix of Glycoproteins (Proteoglycans)
Extracellular Matrix
Proteins that link other proteins together into a continuous unit and helps connect adjacent cells together are major roles of the….
Extracellular Matrix
In Eukaryotic cells, each organelle has its own set of ___________ which carry out most of the functions of that organelle
Proteins
Most proteins are synthesized on Ribosomes in the ___________
Cytoplasm
If proteins are not destined for an organelle, then they will stay in the _______________
Cytoplasm
Many proteins take the first step in sorting them to organelles as they are ____________
Translated
The first 12-20 amino acids in Cotranslational Sortingare ____________ and form an ER Sorting Signal
Non-polar
A special protein, ________________, finds and binds the signal (Hydrophobic amino acids)
Signal Recognition Protein (SRP)
SRP drags the Ribosome to the _________ and attaches to the SRP Receptor
ER
When SRP docks with the Receptor, the protein chain is threaded through the ______________________
Channel Protein
The protein that is threaded through the channel protein is then threaded through the ER so it will end up in the _____________ of the ER. The SRP is now finished and leaves
Lumen
After the proteins are translated, they are packaged into ___________ for transport to the destination organelle
Vesicles
The vesicles destined for an organelle have specific _________ embedded in the membrane to help concentrate the proteins being carried and to help the vesicle fuse with the proper target organelle
Proteins
Proteins that are destined for the Nucleus, Microbodies, Mitochondria and Chloroplast are synthesized on ______________ in the Cytoplasm are sorted after they are made
Ribosomes
The first 12-20 amino acids in post-translational sorting on these proteins are special sequences which act as a ______________ ___________
Sorting Signal
The Transit Sequence is bound and transported to a receptor protein on the outer _______________ membrane
Mitochondrial
______________ proteins keep the protein in an unfolded condition so it can be threaded through the channel protein more easily
Chaperone
The protein is threaded through a channel protein where it is delivered to the ____________ and its signal sequence is removed. The Chaperone protein detaches and assumes its active shape ti become active in the duties of the ___________________
Matrix
Mitochondria
___________ proteins are unique in that their signal or transit sequences are not removed
Nuclear
The position of the _________ keeps changing with each cell division and Nuclear proteins must be gathered and delivered to the new _____________
(same word in both blanks)
Nucleus
