Chapter 2 Cells

Macrophages

A type of Phagocyte located in body tissues

Neutrophils

A type of phagocyte and is also a white blood cell

Phagocytes

Able to carry out Phagocytosis.

Transcytosis

Active process also can be used to successively move a substance into, across, and out of a cell vesicles undergo endocytosis on one side of a cell, move across the cell and then undergo exocytosis on the opposite side vesicles fuse with the plasma membrane and release their content on ECF Transcytosis occurs most often across the epithelial cells that line blood vessels and is a mean for materials to move between blood plasma and interstitial fluid

Flagella

Are similar in structure to cilia but are typically much longer; usually moves and entire cell sperm

How does phagocytosis work?

Begins when the particle binds to a plasma membrane receptor on the phagocyte, causing it to extend pseudopods, projections of its plasma membrane and cytoplasm. Pseudopods surround the particle outside the cell, membranes fuse to form a vesicle called phagosome, which enters the cytoplasm. Phagosome fuses with one or more lysosomes and lysosomes break down the ingested material. Any undigested materials in the phagosome remain indefinitely in a vesicle called residual body. Residual bodies are either secreted by the cell via exocytosis or they remain stored as lipofuscin granules

Process of receptor-mediated endocytosis: Binding

Binding: on the ECF side of the plasma membrane, an LDL particle that contains cholesterol binds to a specific receptor in the plasma membrane to form a receptor-LDL complex receptors are integral membrane proteins that are concentrated in regions of the plasma membrane called clathrin-coated pits a protein called clathrin attaches to the membrane on its cytoplasmic side. Many clathrins come together forming a basket like structure around the membrane to fold inward (invaginate) Uncoating Fusion with endosome Recycling receptors to the plasma membrane Degration in lysosomes

medial cisternae

Cisternae between cis face and trans face/ entry or exit

Proteasomes

Continuous destruction of unneeded, damaged, or faulty proteins is the function of proteasomes, tiny barrel-shapped structures consisting of four stacked rings of proteins around a central core

plasma

ECF in blood vessels

lymph

ECF in lymphatic vessels

Golgi Complex

First step in the transport pathway is through an organelle called the golgi complex consist of 3-20 cisternae-small flattened membranous sacs with bulging edges that resemble a stack of pita bread. more extensive in protein secreting cells.

Peroxisome by product

Hydrogen peroxide is a byproduct of oxidation reaction is hydrogen peroxide a potentially toxic product

receptor-mediated endocytosis

Imports material needed by the cells highly selective, cells take up specific ligands. Vesicle forms after a receptor protein in the plasma membrane recognizes and binds to a particle in the ECF; takes up LDL,transferrin, and vitamins

Vesicle formation

Invaginated edges of the membrane around the clathrin- coated pit fuse, and a small piece of the membrane pinches off. The resulting vesicle, known as a clathrin coated vesicle, contains the receptor-LDL

Microtubules

Largest of the cytoskeletal components, microtubules are long, unbranched hollow tubes composed mainly of protein called tubulin centrosomes are the site where microtubules will initiate; Microtubules grow outward from the centrosome towards the periphery of the cell help determine cell shape and function in the intracellular transport of organelles, such as secretory vesicles, and the migration of chromosomes during cell division participates in movement of the cilia and flagella

Centrosome

Located near the nucleus, consist of two components: a pair of centrioles and pericentriolar material

Autolysis

Lysosomal enzymes may also destroy the entire cell that contains them, a process known as autolysis Occurs in pathological conditions and is responsible for tissue deterioration that occurs immediately after death

Secretory vesicles

Membrane enclosed vesicles called secretory vesicles form inside the cell, fuse with plasma membrane, and release their contents into ECF

Mircofilaments functions

Movement and mechanical support with respect to movement, microfilaments are involved in muscle contractions, cell division, and cell locomotion mechanical support is responsible for basic strength and shapes of cells. Microfilaments anchor the cytoskeleton to integral proteins in the plasma membrane. Also provides support for nonmotile, microscopic fingerlike projections of the plasma membrane called microvilli

Cilia/ cilium

Moves fluid along a cells surface numerous, short, hairlike projections that extend from the surface of the cell each cilium contains a core of 20 microtubules surround by plasma membrane the 20 microtubules are arranged with one pair in the center surrounded by nine clusters of two fused microtubules. Each cilium is anchored to a basal body just below the surface of the plasma membrane

Active transport (transport by transporter proteins)

Process in which substances are transported across plasma membrane with the expenditure of energy by the cell, typically from an area of lower concentration to an area of higher concentration

Golgi complex function

Proteins arriving, passing by, or exiting the Golgi complex do so through maturation of the cisternae and exchanges that occur via transfer vesicles 1) proteins that are synthesize by ribosomes on the rough ER are surrounded by a piece of the ER membrane, which eventually buds from the membrane surface to form a transport vesicle 2) transport vesicle move toward the entry face of the Golgi complex 3) Fusion of several transport vesicles creates the entry face of the Golgi complex and releases proteins into its lumen 4) Protein move from the entry face into one or more medial cisternae. In the medial cisternae enzymes modify the proteins to form glycoproteins, glycolipids, and lipoproteins. Transfer vesicles that bud off from the edges of the cisternae move specific enzymes back towards the entry face and move some partially modified proteins towards the exit face. 5) Products of the medial cisternae move into the lumen of the exit face 6) Within the exit face cisterna, the products are further modified sorted, and packaged 7) Some processed proteins leave the exit face and are stored in secretory vesicles. Vesicles deliver the proteins to the plasma membrane, where they are discharged by exocytosis into ECF 8) Other processed proteins leave the exit face in membrane vesicles that deliver their contents to the plasma membrane for incorporation into the membrane 9) Other processed proteins leave the exit face in transport vesicles that will carry proteins to another cellular destination

Recycling of receptors to plasma membrane

Receptors accumulate in elongated protrusions of the endosome; they pinch off, forming transport vesicles that return the receptors to the plasma membrane after 10 minutes after it enters a cell

Peroxisomes

Similar to the structure of lysosome but smaller also called microbodies contain several oxidases, enzymes can oxidize various organic substances ex. amino acids and fatty acids as part of normal metabolism enzymes in peroxisomes can also oxidize toxic substances like alcohol; very abundant in the liver without peroxisome byproducts of the metabolism could accumulate and eventually cause cells death Peroxisomes can form from preexisting ones by enlarging and dividing

Degration in lysosomes

The transtport vesicle with LDL particles pinches off as well and fuses with lysosome

transmembrane

Transmembrane: Most integral proteins are transmembrane; ability to span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid

Fusion with endosome

Uncoted vesicle quickly fuses with another vesicle known as an endosome. In an endosme the LDL particles detach from their receptors

Bulk-phase endocytosis or pinocytosis

a form of endocytosis in which tiny droplets of ECF are taken into the cell. No receptor proteins are involved; all solutes dissolved in the ECF are brought into the cell. During bulk-phase endocytosis, the plasma membrane folds inward and forms a vesicle containing a droplet of ECF. Vesicle detaches from plasma and enters the cytosol. Within the cell, the vesicle fuses with a lysosome, where enzymes degrade the engulfed solutes. Resulting in smaller molecules, such as amino acids and fatty acids; Bulk-phase happens in most cells, especially absorptive cells in the intestines and kidneys.

germ cell

a gamete or any precursor cell destined to become a gamete

Endoplasmic reticulum/ ER

a network of membranes in the form of flattened sacs or tubules. extends from the nuclear envelope through out the cytoplasm; So extensive it constitutes more than half of the membranous surfaces within the cytoplasm of most cells

Cytoskeleton

a network of proteins filaments that extends throughout the cytosol

diffusion (Kinetic energy transport)

a passive process in which the net movement of a substance is from a region of higher concentration to a region of lower concentration

Facilitated diffusion (Transport by transporter proteins)

a passive process that is accomplished with the assistance of transmembrane proteins functioning as carriers allows molecules that are to large to fit through the plasma membrane like

ligand (membrane proteins)

a specific molecule that binds to a integral receptors; can be called the ligand of the that receptor

nucleus

a spherical or oval shaped structure that usually is the most prominent feature of a cell red blood cells can have none in contrast with muscle cells which can have many

Passive processes

a substance moves down its concentration gradient or electrical gradient to cross the plasma membrane using its own kinetic energy; no input of cells energy

Cytoplasm Cytosol-ICF Organelles

all cellular contents between plasma membrane and nucleus Cytosol: fluid portion; contains water, dilutes solution, and suspends particles Organelles; cells organs

Uncoating

almost immediately after vesicle is formed it loses the receptors coating the vesicle and becomes uncoated; clathrin molecules either return to the inner surface of the cell membrane or help coat other vesicles inside cells

Catalase in peroxisome

another enzyme in peroxisome that decomposes hydrogen peroxide

somatic cell

any cell of the body other than a germ cell

membrane bound ribosomes

attach to the nuclear membrane and to an extensively folded membrane called the endoplasmic reticulum synthesize proteins destined for specific organelles, for insertion in the plasma membrane, or for export of the cell

glycocalyx & function (structure of membrane)

carbohydrate group attached to lipid- enables cell recognitions with one another enables cell to attache to tissue protects cell from being digested by enzymes in the EFC

enzymes (membrane proteins)

catalyze specific chemical reactions at the end at the inside of outside surface of the cell

somatic cell division

cell undergoes a nuclear division called mitosis and cytoplasmic division called cytokinesis to produce to identical cells each with the same number of chromosome as the original

Selective permeability

cells are selective selectively permeable; only permits some substances to pass more readily than others

active processes

cellular energy is used to drive the substance against its concentration or electrical gradient; uses ATP as energy

ATP

cellular energy used is in form of adenosine triphosphate

Mitochondrial matrix

central fluid filled cavity of a mitochondrion

Pericentriolar material

contains hundred of ring shaped complexes composed of protein tubulin organizing centers for growth of the mitotic spindle which plays a critical role in cell division and for microtubule formation in nondividing cells

Fluid mosaic model

continually moving sea of lipids that contains a mosaic of many different proteins some proteins float freely others attached; lipids act like a barrier to the passage of various substances in or out of cell ; some of the proteins act as gatekeepers regulating other substances and ions

Rough ER

continuous with the nuclear membrane and usually is folded into a series of flattened sacs outter surface of ER is studded with ribosomes, site of protein synthesis Proteins synthesized by the ribosomes attached to the rough ER enter spaces within the ER for processing and sorting creates secretory proteins, membrane proteins, and many organellar proteins

Integral proteins

extend into or through the lipid bilayer and are firmly embedded in it

Nuclear pores

extend through the nuclear envelope is continuous with the ER and resembles it in structure controls movement of substances between the nucleus and the cytoplasm small molecules and ions move through the pores passively by diffusion RNA and proteins cannot pass through the pores by diffusion; molecules are recognized and selectively transported through the nuclear pore into or out of the pore

Smooth ER

extends from the rough ER to form a network of membrane tubules no ribosomes contains unique enzymes that make it function in many more ways than rER synthesizes fatty acids and steroids, such as estrogen and testosterone in liver cells, enzymes of the smooth ER help release glucose into the bloodstream and inactivate or detoxify lipid soluble drugs or potential harmful substances such as alcohol, pesticides, and carcinogens.

Golgi Complex cis face/ entry

faces rough ER

Golgi Complex trans face/ exit

faces the plasma membrane

Interstitial body fluid (ECF)

fills the microscopic spaces between cells in tissue cells

extracellular fluid ECF

fluid outside cells in blood vessels as plasma and in lymphatic vessels lymph -ECF fills the microscopic spaces between the cells of tissues is called interstitial body fluid

intracellular fluid ICF / cytosol

fluid within cells

Phagocytosis

form of endocytosis in which the cell engulfs large solid particles, such as worn out cells, whole bacteria, or viruses. Only Phagocytes cells

Plasma membrane

forms the cells flexible outer surface; separates cells internal environment form external environments regulates flow of material into and out of cell establishing adequate environment for normal cell activities plays key role between cell communication

Mitochondria

generates most of the ATP through aerobic respiration aka the powerhouse a cell can have hundreds or thousands depending on the cell activity

Cell identity markers (membrane proteins)

glycoproteins and glycolipids often serve as a cell to -recognize other cells of the same kind during tissue formation -recognize and respond to potentially dangerous foreign cells

Genes

hereditary units contained by chromosomes; controls most aspect of cellular structure and function

Mitochondrial cristae

inner mitochondrial membrane that consist of a series of folds the folds of the cristae provide an enormous surface area for the chemical reaction that are part of the aerobic phase of cellular respiration

nucleoli

inside the nucleus functions producing ribosomes

glycoproteins ( structure of membrane)

integral proteins with a carb group attached

Reproductive cell division

is the mechanism that produces gametes, the cells needed to form the next generation of sexually producing organisms

nucleus

large organelle- contains most DNA

Secretory cells

liberate digestive enzymes, hormones, mucus, or other secretions

endocytosis

materials move into a cell in a vesicle formed from the plasma membrane

exocytosis

materials move out of a cell by the fusion of vesicles formed inside a cell with plasma membrane

Lysosomes

membrane enclosed vesicles that form from the golgi complex contain up to 60 digestive enzymes; capable of breaking a wide variety of molecules recycles the cells own structures; Can engulf another organelle, digest it, and return the digested components to the cytosol for reuse helps replace organelles

Protein filaments 3 types

microfilaments intermediate filaments microtubules

Outer mitochondrial membrane and inner mitochondrial membrane

mitochondrial membranes with fluid in between them

Peripheral proteins

not as firmly embedded in membrane and are attached to lipids or integral proteins

apoptosis

orderly genetically programmed death of a cell

carriers or transporters (membrane proteins)

other integral proteins act as carriers; selectively moving a polar substance or ions from one side of the membrane to the other

Osmosis (kinetic energy transport)

passive process the net movement of water molecules through a selectively permeable membrane from an area of higher water concentration to a lower water concentration

aquaporins (kinetic energy transport)

pores made of integral proteins and between neighboring phospholipids molecules in the membrane; movement continues until equilibrium is reached

Autophagy

process in which an organelle is digested the organelle to be digested is enclosed by a membrane derived from the ER to create a vesicle called autophagosome

linkers (membrane proteins)

proteins that anchor the plasma membrane of neighboring cells to one another or to protein filaments inside and outside the cell; peripheral cells work well as linkers

receptors (membrane proteins)

receptors serve as cellular recognition sites

Exocytosis

releases material from cell; all cells conduct exocytosis 1) Secretory cells that liberate digestive enzymes, hormones, mucus, or other secretions 2) Nerve cells that release substances called neurotransmitters 3) Can also be used to release waste Membrane enclosed vesicles called secretory vesicles form inside the cell, fuse with plasma membrane, and release their contents into ECF

Nuclear envelope

seperates the nuclei with cytoplasm. Both layers are lipid bilayers similar to the plasma membrane

Chromosome

single DNA molecule associated with several proteins

Ribosomes

sites of protein synthesis. Tiny structures of Ribosomal RNA and many ribosomal proteins consist of 2 units once they are produced by the nucleolus they exit the nucleus and join together in the cytosol where the become functional

Vesicles

small spherical, membranous sac formed by building off from an existing membrane -they transport substances from one structure to another within cells, take in substances from ECF or release substances into ECF

Centrioles

the cylindrical structures, each composed of nine structures of 3 microtubules arranged in a circular pattern

ion channels (membrane proteins)

the pore that some integral proteins have that allows specific ions to come in or out such as potassium ions

Microfilaments

the thinnest elements of the cytoskeleton are concentrated at the periphery of a cell; composed of actin and myosin. A core of parallel microfilaments within a microvillus supports it and attaches it to another parts of the cytoskeleton Mircovilli increases surface area of the plasma and are abundant on the surface cells that line the small intestine

Autophagosome

the vesicle made of membrane from the ER that encloses the organelle thats going to be digested vesicle fuses with a lysosome this way liver cells recycle about half their cytoplasmic contents every week

Intermediate filaments

thicker than microfilaments but thinner than microtubules; strong Found in parts of the cell subject to mechanical stress, and help anchor organelles such as the nucleus and attach cells to one another

meiosis

two step division called meiosis in which the number of chromosomes in the nucleus is reduced by half

lysosome

type of vesicle inside cell; contains many digestive enzymes. Certain enzymes break down the large protein and lipid molecules of the LDL particle into amino acids, fatty acids, and cholesterol; the cell then uses the content to rebuild cells membrane, produce steroids like estrogen, amino and fatty acids

free ribosomes

unattached ribosome to any structure in the cytoplasm. Primarily synthesizing proteins inside the cell

lipid bilayer & make up HOW DOES IT WORK!

what the plasma membrane is made out of- structural framework 2 back to back layers made up of 3 types of lipid molecules-phospholipids,cholesterol, and glycolipids 75% phospholipids 20% cholesterol 5% glycolipids