ch 4 Evolutionary origin Flashcards
is an organelle in eukaryotic cells that contains most of the cell’s genetic material
nucleus
The endomembrane system consists of which of the following?
- Endoplasmic reticulum
- Lysosomes
- Vacuoles
- Nuclear envelope
- Golgi apparatus
The disconnected organelles of the endomembrane system pass materials to each other via
- vesicles
Which of these statements isnota part of the cell theory?
All cells are replaced.
The interaction of which of the following macromolecules plays an important role in the formation of living cells?
RNA
DNA
proteins
list the origin of life in proper order first to last
- nucleotides and amino acids produced prior to the existence of cells
- nucleotide become polymerized to form RNA and DNA and amino acids became polymerized to form proteins
- Polymer became enclosed in membrane
- polymer enclosed in membranes acquire cellular properties
Head/Hinge/Tails cell
- HEAD: site where ATP binds and is hydrolyzed
- Hinge: site that bends in response to ATP binding and hydrolysis
- Tail:Region that is attached to other proteins or to other molecules
Deep-sea Vent hypothesis
Extreme temps, metal ion and H2S and NH3 interact leading to organic molecules
Extraterrestrial Hypothesis
Organic molecules travel to earth from meterotires
Reducing Atmosphere Hyptohesisi
Water vapor, hydrogen gas, methane and ammonia interact in the absence of oxygen to produce organic molecules
Which macromolecule forms the foundation for the structure and activities of living cells
Protein
In addition to chemicals like hydrogen sulfide, iron, and ammonia, deep-sea vents are also a source of ______, which may have been important for producing organic molecules
heat
The work of Miller and Urey demonstrated the synthesis of
precursors to organic molecules.
what may have formed in the temperature gradient between the extremely hot deep-sea vent water and the cold water that surrounds the vent?
organic molecules
The three key functions of RNA are its ability to ________ info in its nucleotide sequence, its capacity for _________, and its ability to perform a variety of _________ functions
- Store;
- Self-Replication
- Catalytic
Which of the following were formed during the second stage in the origin of life?
Complex organic polymers
Chemical evolution occurs when:
a population of molecules changes over time to have different chemical composition
Which of the following is true of protobionts?
Not capable of precise self-reproduction
The RNA world is a hypothetical period on Earth when RNA molecules performed what functions
- genetic information
- enzymatic catalysis
What are key functions of RNA?
The ability to store information in its nucleotide sequence
The capacity for self-replication
The ability to function as ribozymes
the complete set of genetic material present in a cell or organism is____
genome
In the concept of the _________, scientists envision that RNA served to both carry the genetic information and perform catalytic functions needed for life
RNA world
What is the advantage of using DNA as a molecule that stores information for the synthesis of RNA molecules
- RNA could enhance its other functions
Prokaryotes differ from eukaryotes because they lack a membrane-enclosed _____, which houses the DNA.
Nucleus
a ___ is defined as the entire complement of an organism’s genetic material
genome
What do prokaryotes lack
Nucleus
Which of the following is an example of a droplet organelle?
Nucleolus
Is it possible for cells from the same multicellular organism to have different proteomes?
Yes, because cells produce different proteins.
What best explains why most cells are small?
Cells must be small to be able to take up nutrients efficiently.
Metabolism
- the sum of the chemical reactions by which cells produce the materials that utilize the energy that are necessary to sustain life
- involves a series of steps called metabolic pathway
- each step in a metabolic pathway is catalyzed by a specific enzyme
Explain how different cells in the same organism can produce different proteomes.
- Two different cell types may produce different amounts of the same protein.
- There may be differential gene regulation and alternative splicing.
- Different cell types may alter their proteins in different ways.
Most cells are small because the ability to exchange nutrients and wastes is limited by the:
surface area
is the region of a eukaryotic cell that is outside the membrane-bound organelles but inside the plasma membrane.
cytosol
What term describes the chemical processes that occur within living cells in order to maintain
Metabolism
Microtubules are cytoskeletal structures composed of the protein
tubulin
An _____ filament has a staggered alignment of different proteins such as keratin and lamin and may be found in such places as skin and kidney cells.
Intermediate
A(n) ______ filament has two intertwined strands of protein and is often found near the plasma membrane anchored to other proteins.
actin
long, hollow, cylindrical structures about 25nm in diameter composed of subunits called alpha and beta protein tubulin. important for cell shape and organization; organelles such as the golgi apparatus are often attached to this filament
Microtubules
Which of the following eukaryotic appendages function via bending movements?
Both cilia and flagella
which of these statements best describes actin filaments?
a spiral of two intertwined strands of protein
which of these statements best describes intermediate filaments
twisted filament that can be composed of keratin or lamin
The arrangement of microtubules in eukaryotic cilia and flagella made from a circle of microtubule pairs and two central microtubules is referred to as the ______ structure.
9+2
In eukaryotic cells, cilia are typically ______ than flagella.
- shorter and more numerous
in eukaryotic cilia and flagella is ____ made from 9 doublets and two central singlets.
microtubules
The association of DNA and proteins in a non-dividing eukaryotic cell is called____
chromatin
The _________ system forms a secretory pathway that allows for the movement of larger molecules of the cell.
endomembrane
Along the disconnected organelles of the secretory pathway that comprise the endomembrane system _______ pass(es) materials
vesicles
The flattened, fluid-filled tubules that make up the endoplasmic reticulum are called
cisternae
What are the functions of the rough endoplasmic reticulum?
- Insertion of membrane proteins
- Protein sorting
- Glycosylation of proteins and lipids
The complex of DNA and proteins in a eukaryotic cell is referred to as
Chromatin
What organelle synthesizes lipids, stores calcium ions, and detoxifies harmful organic molecules?
smooth endoplasmic reticulum
Where does the assembly of ribosome subunits occur?
Nucleolus
Which of the following statements best describes the structure of the Golgi apparatus?
A stack of flattened membranes, each enclosing a single compartment
the Golgi apparatus sorts and processes proteins, then packages them into secretory ________ that fuse with the plasma membrane.
- vesicles
The endoplasmic reticulum is a network of membranes that formed flattened tubules called:
cisternae
Lysosomes contain enzymes called acid
hydrolases
What organelle holds membrane proteins as they are being synthesized, glycosylates proteins and lipids, and plays a role in protein sorting?
Rough endoplasmic reticulum
Specialized compartments that function in storage, regulation of cell volume, and degradation are called:
vacuoles
What are the functions of the smooth endoplasmic reticulum?
- Detoxification of harmful organic molecules
- Synthesis and modification of lipids
- Storage of calcium ions
What is the primary function of peroxisomes?
Synthesis and breakdown of organic molecules
The _________ apparatus consists of a stack of flattened membranes, each enclosing a single compartment
Golgi
Which of the following are considered semiautonomous organelles?
- Mitochondria
- Chloroplasts
The functions of the Golgi apparatus include:
- protein sorting
- secretion
- processing of proteins and lipids
Lysosomes contain a variety of acid hydrolyses that are able to break down:
- nucleic acids
- lipids
- proteins
- carbohydrates
The functions of vacuoles include:
- storage
- regulation of cell volume
- degradation of macromolecules
the ______ are cellular organelles, which use chemical energy stored within the covalent bonds of organic molecules to produce ATP
- Mitochondria
in mammals, large numbers of __________ are found in liver cells, where toxic molecules accumulate and are broken down.
peroxisomes
The function of a chloroplast is to capture the light energy necessary for the synthesis of which of the following organic molecules in the process of photosynthesis _____
Glucose
Which of the following genomes are typically composed of a singular circular chromosome?
- mitochondrial genome
- bacterial genome
- chloroplast genome
The primary function of mitochondria is the synthesisof ___
ATP
In order for proteins made in the cytosol to be directed to the appropriate organelle, they must have the proper_______ signal within their amino acid sequence
sorting
In plants, photosynthesis occurs in semiautonomous organelles called ___
chloroplasts
The extracellular matrix (ECM) is composed of two major macromolecules. These are
proteins and polysaccharides.
What are the functions of the extracellular matrix in animals:
- provides strength
- participates in cell signaling
- provides structural support
- organizes cells and binds body parts together
The genomes of chloroplasts and mitochondria are most similar to:
a bacterial chromosome
the _____________ theory suggests that mitochondria and chloroplasts originated from bacteria that took up residence within a primordial eukaryotic cell.
endosymbiosis
What macromolecules found in the extracellular matrix (ECM) provide strength and elasticity?
Proteins
True or false: In eukaryotic cells, the proteins synthesized in the cytosol and which function in the organelles, must be directed to the correct cellular location with proper signals located in their amino acid sequence.
True
Glycosaminoglycans and proteoglycans form a gel-like component in the extracellular matrix because their negative charges attract:
water
The most abundant macromolecules of the extracellular matrix (ECM) are
proteins and sugars
In animal cells, what provides strength and structural support for the cell and also plays a role in cell signaling?
- extracellular matrix
What molecule is found in the secondary cell wall but NOT the primary cell wall?
Lignin
Which of the following genomes are typically composed of a singular circular chromosome?
- bacterial genome
- chloroplast genome
- mitochondrial genome
True or false: The extracellular matrix of animals tends to be thicker, stronger, and more rigid than the cell walls of plants.
False
What is the function of structural proteins found in the extracellular matrix (ECM)?
impart tensile strength and elasticity
What are the functions of the plant cell wall?
- It prevents cells from bursting when water enters them.
- It maintains cell shape.
- It provides mechanical support.
- It helps to determine the direction of cell growth.
How do glycosaminoglycans (GAGs) protect cells from compression?
Their negative charge allows them to attract water, giving the extracellular matrix a gel-like quality.
The extracellular matrix (ECM) is composed of two major macromolecules. These are
proteins and polysaccharides.
Which of the following are found in bacteria, animal cells AND plant cells?
- Ribosomes
- Cytoplasm
- Plasma membrane
True or false: The secondary cell wall structure is relatively similar in nearly all cell types and species, whereas the structure of the primary cell wall is more variable.
False
Although they both provide tensile strength and resistance to compression, the extracellular martix of animals and cell walls of plants differ because the cell walls of plants
- are more rigid
- are able to prevent osmotic lysis
- are thicker
What are the four interacting parts of a eukaryotic cell?
- cytosol
- endomembrane system
- nucleus
- semiautonomous organelles
