Chapter 3:Cells Flashcards
Define cell nucleus
The nucleus house is genetic material that directs all cell activities. It is large roughly spherical structure enclosed by double layered nuclear envelope
What is a double membrane surrounding the cell nucleus, that separates the nucleus from the cytoplasm and also consists of inner and outer lipid bilayer membranes. Has protein lined channels called nuclear pores that allow certain molecules to exit the nucleus
Nuclear envelope
What is a complex opening formed with about 100 types of proteins that’s large enough to let out RNA molecules that carry genes messages not large enough to let out DNA itself must remain in nucleus
Nuclear pore
What is the structure near the Golgi apparatus and nucleus that is non-membranous and consists of two hollow cylinders called centrolies that lie at right angles to each other each centrioles are composed of nine groups of three microtubules
Centrosome
What is the function of a centrosome?
During mitosis they distribute chromosomes to new formic cells it is also a cellular organelle that separates the chromosomes into two cells from one during cell division.
Define centrioles:
Cellular structure built of microtubules that organizes mitotic spindle
What is the elongated fluid-filled sex of an organelle that are oblong and vary someone in size and shape it has an outer and inner layer the inner layer is folded extensively into portions these increase in surface area connected to Chris day our enzymes that control some of the chemical reactions
This is the mitochondria.
Mitochondrial DNA is?
Essential to the normal function of metabolic pathways in mitochondria.
What is the function of mitochondria?
Housing most of the biochemical reactions that extract energy from nutrients and digested food. They move slowly through the cytoplasm and reproduced by dividing. Enzymes connected to Chris day that controls some chemical reactions that release energy from nutrients and process called cellular respiration mitochondria store this energy otherwise known as ATP. A cell can easily use energy stored as ATP very active cells such as muscle cells have thousands of mitochondria mitochondria also contain a small amount of their own DNA.
What is an organelle of tiny membrania sacs they butt off sections of Golgi apparatus membranes?
This is a lysosome
Describe the function of a lysosome
They contain enzymes that break down worn out cell parts and debris. They maintain the acidic pH that enables enzymes to function and shield the rest of the cell from acidic conditions. Lysosomal enzymes break down nutrient molecules, or ingested materials. Lysosomes destroy one cellular parts, and digest certain white blood cells of bacteria an example of this is in liver cells lysosomes break down cholesterol toxins and drugs.
What is an exosome
Vessels that deliver proteins and lipids to other cells they remove debris transport immune system molecules, from cell to cell and provide vast communication Network among cells
What is a vesicles function
Store or transport substances within a seller between cells. Larger vesciles bring solid material from outside cells into cytoplasm. Smaller vesciles shuttle material from the rough endoplasmic reticulum to the Golgi apparatus as part of the secretion process.
Define Vesciles
Membraneous sacs. Larger vesciles that contain mostly water form when part of a cell membrane folds inward and pinches off
Define Golgi apparatus
Organelle that prepares and modifies proteins and glycoproteins for secretion. Stack of 5 to 8 flattened membranous sacs (resembles pancakes) a cell may have multiple Golgi apparatus enclosed and vesicles composed of membrane from the endoplasmic reticulum.
What is the movement into and out of the cell an example would be a transport vesicles may move to infuse with the cell membrane releasing its contents to the outside as a secretion
This is an example of exocytosis
What is the function of Golgi apparatus?
Refines, packages, and transports protein synthesized by ribosomes associated with the endoplasmic reticulum. Proteins arrive at Golgi apparatus enclosd in vesciles composed of membrane from the endoplasmic reticulum. Sugar molecules attached to some proteins in endoplasmic reticulum are called glycoproteins these vesciles fuse with the membrane and at innermost end of Golgi apparatus these are specialized to receive glycoproteins as they pass from layer to layer through the Golgi stacks they are modified chemically. Some sugars may be added or removed and proteins short and when they reach the outermost layer they are packaged in bits of Golgi membrane, which but off to form transport vesciles.
Define the nucleus
The word means “little nucleolus”it’s a small dense body composed of largely RNA and protein has no surrounding membrane and forms a specialized region of certain chromosomes together. Ribosomes form here and then they migrate through nuclear pores to the cytoplasm
What consists of loosely coiled fibers of DNA and protein, condensed to form chromosomes during mitosis, when cell begins to divide they coil tightly and then they condense to form individual chromosomes. At times the chromatin unwind to permit access to information in certain genes
Chromatin.
What are some passive mechanisms that do not require cellular energy?
Diffusion, facilitated diffusion, osmosis and infiltration
Describe the function of the endoplasmic reticulum.
The membraneous parts interconnected and communicate with the cell membrane, the nuclear envelope, and other organelles. It also provides a vast tubular Network to transport molecules from a cell part to another the endoplasmic reticulum participates in synthesis of protein and lipid molecules. These molecules may leave the cell as secretion or used within the cell for functions like producing new endoplasmic reticulum or cell membrane as the cell grows. It also acts as a quality control center for the cell. It’s chemical environment enables a forming protein to start to fold into the shape necessary for its function, can I identify and dismantle a misfolded protein. Proteins being synthesized move through the endoplasmic reticulum tubules to another organelle called the Golgi apparatus.
This is the contents of the cell, including the gel-like cytosol and organelles except the nucleus this is enclosed by the cell membrane within the cytoplasm the organelle are structure and cell with special functions. This is not static or still they either are moving inside the cell or partake in ongoing biochemical activity.
This is what we call a cytoplasm
Please define organelle
These perform a specific function, portion of biochemicals that might harm other cell parts. They dismantled debris, process secretions, and extract energy from nutrients, they also interact with each other creating vast networks throughout the cell and they also conduct activities such as food breakdown, producing energy, heat and protein lipid production / packaging and they also maintain the cell shape.
Describe in depth about the cell membrane
It’s an actively functioning part of living material that also regulates substances in and out of the cell and is the site of a lot of biological activity it also helps attach to certain other cells and helps form tissue.
This is a molecular communication process, a series of molecules part of cell membrane to form pathways and detecting signals from outside the cell to transmit them inward.
This is what we call signal transduction
What is a cell?
A cell is the smallest unit of life there’s over 30 trillion in the human body, a cell structure must display all characteristics of life which is responsiveness, respiration, digestion, growth, absorption, assimilation, circulation, execration, movement, and reproduction.
This is a selectively permeable outer boundary of the cell that consists of phospholipid bilayers, embedded with proteins that can also be called the plasma membrane. This also encloses the cell
This is called the cell membrane.
This is the dense core of an atom composed of protons and neutrons it is cellular organelle enclosed by double layered porous membrane and containing DNA it also houses genetic materials and controls cellular activities and the cytoplasm and produces ribosomes.
This is called the nucleus
These are classified according to their specialized positions in relation to phospholipid bilayer they vary in shape and they may be globular rod like or fibrous
These are membrane proteins
What are the types of membrane proteins?
Integral proteins, transmembrane proteins, peripheral membrane proteins
The cell membrane is called the “fluid mosaic” because?
It’s proteins are embedded in an oily background and therefore can move like ships on a sea
Describe each membranes protein function
They provide specialized functions to the membrane, they form receptors on cell surface to bind incoming hormones or growth factors, starting signal transduction. They also transport ions or molecules across the cell membrane. They also form ion channels in phospholipid bilayer that allow only particular ions to enter or leave the cell.
These extend through the lipid bilayer and may protrude from one or both faces
Integral proteins
Integral proteins that go through bilayer and extend through both faces of the membrane
Transmembrane proteins
Structures that have specific shapes that fit and hold certain molecules many are particularly embedded in cell membrane
Peripheral membrane proteins
Specific for calcium, sodium, potassium, or chloride, a cell membrane may have a few thousand channels for specific each ions, they open and close like a gate under specific conditions an example of this would be change in electrical forces.
Ion channels
These are complex organelles composed of membrane bound flattened sacks cylinders and fluid-filled bubble-like sacks called vesciles winds from the nucleus out toward the cell membrane and many places the endoplasmic reticulum’s outer membrane is studded with ribosomes which give the endoplasmic reticulum texture appearance this section we call the rough endoplasmic reticulum as endoplasmic reticulum nears the cell membrane, it becomes more cylindrical and the ribosomes become spares, they are no longer associated with the endoplasmic reticulum this we called the smooth endoplasmic reticulum along the smooth are the enzymes.
This is the definition of endoplasmic reticulum.
A vescile is known as
Membranous cytoplasmic sac formed by an infolding of the cell membrane or pinching off membranes within a cell
An organelle composed of RNA and protein, tiny spherical structures, they are scattered into the cytoplasm and bound to the endoplasmic reticulum
This would be a ribosome
What is the ribosomes function?
There are structural support for protein synthesis and provide enzyme activity to help join amino acids and structural support and enzymatic activity to link amino acids to synthesize proteins
What is a polysome.
Clusters of ribosomes in the cytoplasm
What is a membranous sec abundant in liver and kidney cells
Peroxisomes
What is the function of peroxisomes
They contain enzymes that catalyze reactions that decompose/release hydrogen peroxide they also break down fatty acids and detoxify alcohol. These enzymes are different than those of a lysosome.
Name the organelles that has specific function and carrying out cell activities in the cytoplasm
Ribosomes, endoplasmic reticulum(rough and smooth) , Golgi apparatus, mitochondria, lysosomes, peroxisomes, Vesciles,
Name the other cellular structures that aren’t an organelle but part of the cytoskeleton
Microfilaments, microtubules, centrosome, cilia and flagella
What are microfilaments and microtubules
They are types of thin thread like strands in the cytoplasm they form the cytoskeleton and are part of certain structures like the cilia and centrosomes and flagella that have specialized activities.
Microfilaments are
Tiny rods of the protein actin form a meshwork or bundle and provide cell motility or movement an example would be the muscle cells as they aggregate forming myofibrous which help these cells contract.
Microtubules are
Long slender tubes, diameter is 2 to 3 times those of microfilaments they’re composed of molecules of globular protein tubulin and attached to the spiral to form a long tube. These are important in cell division because they provide structure and act as information carriers in neurons.
Intermediate filaments are
They lie between the microfilaments and tubules and diameter and are made of different proteins in different cell types abundant and skin cells were resists stress and they are in neurons
This is a thin and flexible composed mainly of lipids and proteins with a few carbohydrates and maintain structural integrity of the cell it is selectively permeable and it’s basic framework is a double layer bilayer of phospholipid molecules, each molecule includes a phosphate group and two fatty acids bound to a glycerol molecule. The water soluble phosphate heads are hydrophilic and form the intracellular and extracellular surfaces of the membrane the water and soluble fatty acid or tails are hydrophobic and make up interior / middle of membrane. The lipid molecules can move sideways with plane of membrane the membrane layers from a soft flexible but stable fluid film
This is called the cell membrane.
What is hydrophilic
Water lovers
What is hydrophobic
Water fears
This is one that regulates which substances enter or leave
Selectively permeable membrane
This is the sales framework of protein microfilaments and tubules
Cytoskeleton
The phospholipid bilayer is impermeable to water soluble molecules such as
Amino acids, sugar, proteins, nucleic acids, and certain ions
What do cholesterol molecules embedded in the cell membranes interior help
They help make membrane less permeable to water soluble substances the rigid structure of the molecule stabilizes the cell membrane.
CYT
Cell cytosol (fluid) an organelles between the cell membrane and nuclear envelope
ENDO-endoplasmic reticulum
Within complex of membraneous structures in a cytoplasm
HYPER HYPERTONIC
Abovesolution with greater concentration of solutes greater osmotic pressure than cytoplasm
HYPO HYPOTONIC
betweenstage between end of cell division and beginning of the next
