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