Ch. 6 Flashcards
A netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus.
Nuclear Lamina
A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each ________ consists of one very long DNA molecule and associated proteins. (A bacterial _________ usually consists of a single circular DNA molecule and associated proteins. It is found in the nucleoid region, which is not membrane bounded.) See also chromatin.
Chromosome
The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, ________ exists in its dispersed form, as a mass of very long, thin fibres that are not visible with a light microscope.
Chromatin
Which cell typically has 46 chromosomes in it? But it’s sex cell only contains about 23
Human
A specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along with ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly.
Nucleolus
Appears through the electron microscope as a mass of densely stained granules and fibres adjoining part of the chromatin.
Nucleolus
A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large and a small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus.
Ribosome
This ribosome is suspended in cytosol
Free
Bound ribosomes are attached to the outside of
endoplasmic reticulum
nuclear envelope
Bound Ribosomes make proteins that are destined for:
insertion into membranes
packaging within certain organelles such as lysosomes
export from the cell (secretion).
Cells that specialize in protein secretion frequently have a high proportion of
Bound Ribosomes
Most of the proteins made on free ribosomes function within the cytosol, what is an example
enzymes that catalyze the first steps of sugar breakdown
The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles
Endomembrane system
What is included in the Endomembrane system?
includes the plasma membrane,
the nuclear envelope,
the smooth and rough endoplasmic reticulum,
the Golgi apparatus,
lysosomes,
vesicles,
vacuoles.
List some of the tasks carried out by the endomembrane system
synthesis of proteins,
transport of proteins into membranes and organelles or out of the cell,
metabolism and movement of lipids,
detoxification of poisons.
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Endoplasmic Reticulum
The ER membrane separates the internal compartment of the ER, called the ER lumen (cavity) or cisternal space, from
Cytosol
The ER consists of a network of membranous tubules and sacs called
Cisternae
region of endoplasmic Reticulum that lacks ribosomes
smooth ER
Portion of endoplasmic reticulum that is studded with ribosomes
rough ER
Smooth ER functions (depending on cell type)
synthesis of lipids
metabolism of carbohydrates
detoxification of drugs and poisons
storage of calcium ions.
What are some hormones created by the smooth ER
Steroids in animal cells
Sex hormones of vertebrates
Various steroid hormones secreted by adrenal glands
testes and ovaries are rich in what type of ER
smooth
Detoxification usually involves adding _________ to drug molecules, making them more soluble and easier to flush from the body.
hydroxyl groups
In fact, barbiturates, alcohol, and many other drugs induce the proliferation of smooth ER and its associated detoxification enzymes, thus increasing the rate of detoxification. Which means….
increases tolerance
What is smooth ER responsible for in muscle cells.
Pumping calcium ions from the cytosol into the ER lumen
Describe what happens when a muscle cell is stimulated by a nerve impulse
Calcium ions rush back across the ER membrane into the cytosol and trigger contraction of the muscle cell.
A protein with one or more covalently attached carbohydrates
glycoprotein
What attaches carbs to proteins and where is it found
In the ER lumen by enzymes built in to the ER membrane
A small membranous sac in a eukaryotic cell’s cytoplasm carrying molecules produced by the cell.
Transport Vesicle
The region that creates the Transport Vesicle
Transport ER
How does the rough ER membrane grow in place?
By adding membrane proteins and phospholipids to it’s own membrane
What happens to portions of the ER membrane as it expands?
Portions of it are transferred in the form of transport vesicles to other components of the endomembrane system.
An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbohydrates.
Golgi apparatus
Flattened membranous sacs found in Golgi apparatus
Cisternae
Name the two sides of the Golgi stack
Cis face
Trans face
Where is the cis face usually located
Near the ER
What does the Golgi apparatus do to glycoproteins as they pass through?
removes some sugar monomers and substitutes others, producing a large variety of carbohydrates.
What is attached to Golgi vesicles as “identification tags”
phosphate groups
What happens in the Golgi static model?
products in various stages of processing transferred from one cisterna to the next by vesicles.
What happens in the Golgi cisternal maturation model?
the cisternae of the Golgi actually progress forward from the cis to the trans face, carrying and modifying their cargo as they move.
A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists.
Lysosome
Why would Lysosomal Enzymes not be super dangerous if a small amount leak?
Cytosol has a fairly neutral Ph
What is made by the rough ER then transported to the Golgi for further processing?
Hydrolytic Enzyme
lysosomal membrane
How are the proteins of the inner surface of the lysosomal membrane and the digestive enzymes themselves spared from destruction?
the three-dimensional shapes of these proteins protect vulnerable bonds from enzymatic attack.
A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells).
Phagocytosis
When the lysosome breaks down damaged organelles
Autophagy
When lysosome digests food
Phagocytosis
A membrane-bounded vesicle whose specialized function varies in different kinds of cells.
Vacuole
A membranous sac that helps move excess water out of certain freshwater protists.
Contractile Vacuole
In a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances.
Central Vacuole
What major role does the central vacuole play in a plant cell?
Growth
How does the Central Vacuole contribute to cell growth?
as the vacuole absorbs water, enabling the cell to become larger with a minimal investment in new cytoplasm.
Which organelles in eukaryotic cells are responsible for energy conversion.
Mitochondria
Chloroplasts
An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP.
Mitochondria
An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
Chloroplast
The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.
Endosymbiont Theory
Term for cell living within another cell
Endosymbiont
Three supporting ideas of Endosymbiont Theory
- Mitochondria and chloroplasts have double membranes
- Mitochondria and chloroplasts contain ribosomes, as well as multiple circular DNA molecules associated with their inner membranes.
3.Mitochondria and chloroplasts independently grow within the cell
The number of what organelle correlates to the cell’s level of metabolic activity
Mitochondria
An infolding of the inner membrane of a mitochondrion. The inner membrane houses electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP (ATP synthase).
Crista
The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle, as well as ribosomes and DNA.
Mitochondrial Matrix
Where are the Enzymes that make ATP
Inner mitochondrial membrane
What is another example of the structure fitting function within the mitochondria
The Cristae of the inner membrane
What three things are contained within the mitochondrial matrix
Enzymes
Mitochondrial DNA
Ribosomes
True or False
These observations helped cell biologists understand that mitochondria in a living cell form a branched tubular network, seen in a whole cell in Figure 6.17b, that is in a dynamic state of flux.
True
A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular “machinery” used to convert light energy to chemical energy.
Thylakoid
A stack of membrane-bounded thylakoids in the chloroplast. Grana function in the light reactions of photosynthesis.
Granum
The dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; involved in the synthesis of organic molecules from carbon dioxide and water.
stroma
what contains the chloroplast DNA and ribosomes as well as many enzymes.
stroma
What are the 3 compartments of the Chloroplasts
Intermembrane space
Stroma
Thylakoid
One of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts. Plastids are found in cells of photosynthetic eukaryotes.
Plastids
An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen , producing and then degrading hydrogen peroxide .
Peroxisome
Some peroxisomes use oxygen to break fatty acids down into smaller molecules to be transported where for what purpose?
Transported to the Mitochondria and used as fuel for cellular respiration
Function of peroxisomes in the liver
detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen
How do peroxisomes grow larger?
They grow larger by incorporating proteins made in the cytosol and ER, as well as lipids made in the ER and within the peroxisome itself.
A network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signalling functions.
Cytoskeleton
Three types of structures that make up the Eukaryotic cytoskeleton
microtubules, microfilaments, and intermediate filaments.
changes in cell location and movements of cell parts
cell motility
A protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.
motor protein
A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella.
Microtubule
