What is a cell? How do their appearances matter? What are some of the common features they share?
-Cells are the basic functional units of a body
-Their appearances reflect the variety of shapes and sizes which also reflect their diverse functions
-The common features they share are...
- Plasma membrane with proteins
What is the plasma membrane? What do its parts do?
-The plasma membrane is a phospholipid barrier between intracellular and extracellular environments.
-Lipids restrict water soluble molecules & ions
-Protein channels are selectively permeable (they let some things in)
-Proteins and phospholipids move laterally = fluid mosaic model
What is the structure of a membrane phospholipid? How do the phospholipids arrange themselves?
-The membrane phospholipid has...
- A polar head that is hydrophilic
- A nonpolar fatty acid tail that is hydrophobic
-The phospholipids can arrage themselves as...
- A phospholipid bilayer sheet
- A micelle, a droplet of phospholipids that aid in transporting lipids for digestion
- A liposome, that has an aqueous center.
-The arrange themselves so their nonpolar tails are not in contact with any aqueous solutions such as extracellular fluid.
What are membrane proteins and what are their functions?
-Any protein associated with a membrane.
- Integral proteins span membrane
- Peripheral proteins are embedded on one side of the membrane
- "Self" markers for the immune system
- Receptors for hormones and other molecules
- Enzymatic control of cell processes
- Structural support
What is cytoplasm? What does it include?
-Essentially, the guts of the cell (material within a cell) it includes...
- Cytosol: gel-like substance enclosed in cell
- Protein fibers of Cytoskeleton: Microfilaments, intermediate filaments, microtubules.
-THE NUCLEUS IS EXCLUDED, it has it's own little plasm and stuff.
What is the cytoskeleton? What does it do?
-The cytoskeleton is a network of fibers (microvilli, microfilaments, microtubules, intermediate filaments) throughout the cell's cytoplasm.
-The cytoskeleton helps provide cell shape, internal organization, intracellular transport, assembly of cells into tissues, and movement.
How do cytoskeletal proteins work?
-Proteins of the cytoskeleton are not immobile
-Organize intracellular environment and allow the movement of muscle cells and phagocytic cells.
-Also provides a "railway" system for vesicles and organelles.
What are Cilia? What functions do Cilia perform?
-Tiny hairlike cytoplasmic projections with microtubules that extend from the surface of the plasma membrane.
-Propel movement, such as to move the cell or substances, particles adjacent to the cell surface. They are found in the respiratory tract and uterine tubes.
What is a flagellum? What is its function? What is the only cell in the human body that has one?
-Flagellum are a single whiplike structure composed of microtubles that can propel a cell forward or move particles along cell surface.
-A sperm is the only cell in the human body with flagellum.
What is a mitochondria? What function does it perform?
-A structure that contains an inner membrane and outer membrane separated by an intermembranous space with inner membrane folded into cristae.
-The mitrochondria releases energy from food molecules and transforms that energy into usable ATP. (site of energy production)
What is the Rough Endoplasmic Reticulum (ER)? What function does it preform?
-The rough ER is a system of interconnected membrane forming canals and tubles with ribosomes attached.
-The rough (granular) endoplasmic reticulum is the main site protein synthesis and assembles and modifies these proteins.
What is the Smooth Endoplasmic Reticulum (ER)? What function does it perform?
-The smooth endoplasmic reticulum (ER) is a system of interconnected membrane-forming canals and tubules that is agranular in appearance.
-The smooth ER synthesizes lipids, steroids (nonpolar compounds) and is modified in some cells and stores calcium ions.
- Modified in liver & muscle cells (concentrates and stores calcium ions)
What are ribosomes? What functions do they perform?
-Ribosomes are granular particles composed of two subunits which are proteins and ribosomal RNA. They are Located free in cytoplasm or on rough ER.
-Ribosomes synthesize proteins
- Messenger RNA takes genetic information to ribosome so protein can be assembled
What is the Golgi apparatus? What function does it perform?
-The Golgi apparatus consists of a cluster of flattened membranous sacs.
-The Golgi apparatus...
- Receives proteins from one side of the ER
- Modifies and packages these proteins into vesicles
- The vesicles then bud off to fuse with plasma membrane for exocytosis
- It also synthesizes carbohydrates and packages molecules for secretion such as lipids and glycoproteins.
What is endocytosis?
-Endocytosis is a process by which a cell membrane folds inward to taken in substances bound to its surface as a vesicle.
What is exocytosis?
-Passage of material to cell surface by fusing a vesicle with contents to a cell membrane and then opening.
What is phagocytosis?
-Process through which pseudopods (temporary projection of the cytoplasm of certain cells or of certain unicellular organisms) engulf bacteria, dead cells, or organic materials to form a food vacuole.
-Vacuole then fuses with lysosome and bacterium is digested.
-Some white blood cells move by using cytoskeleton by extended pseudopods forward (amoeboid movement)
What are the four major tissues that our organs are composed of? How are these tissues held together?
-Our organs are composed of muscle, nervous, epithelial, and connective tissue.
-The tissues (made of of cells) are connected & held together by various types of cell junctions.
What is muscle tissue? How many types of muscle tissue are there? What are they?
-Muscle tissue are "excitable" cells specialized for contraction.
-There are three types of muscle tissue:
What is connective tissue? What are the different forms of connective tissue?
-Connective tissue is biological tissue that supports, connects, and seperates different types of tissues and organs of the body.
-Connective tissue is characterized by a matrix of protein fibers, and extracelluar material between cells
- Can be gel-like
What is epithelial tissue? Classify it by layer, and layer's associated function. How about by shape?
-Epithelial tissue is membranous tissue that lines/covers internal organs and other internal surfaces of the body and forms glands.
-Epithelial tissue is classifed by number of layers
- Simple for one layer; focuses mainly on secretion, absorption, and material passage.
- Stratified for multiple layers, focuses mainly on protection.
-Epithelial tissue is also classifed by the shape of it's cells.
What is nervous tissue? Where is it located?
-Composed of neurons and glial support cells, it is designed to react to stimuli and bring about response to stimulus.
-Found in brain, spinal cord, and nerves
How does a neuron work?
-Neurons conduct electrical signals
- Dendrites receive signal
- Axon sends signal
- Cell body serves as metabolic (related to chemical activity of a particular substance) center
What is mitosis? What is meiosis? What is the difference between the two?
-Mitosis is the process through which a cell divides into two daughter cells each of which have the same number of chromosomes as the original cell.
-Meiosis is the process through which a cell's nucleus divides into four nuclei, each of which have half the usual number of chromosomes.
-The difference between the two is that...
- Mitosis ends up with 46 chromosomes per cell
- Meiosis ends up with 23 chromosomes per cell
- Mitosis deals with body cells
- Meiosis occurs only in ovaries and testes to produce games such as sperm and eggs.
What is an exocrine gland? What is an endocrine gland? What is the difference between the two?
-An exocrine gland is one whose secretions are transported by ducts to the surface of an organ.
- Digestive enzymes
-An exocrine gland is one whose secretions (hormones) go directly into the blood and travel to distant targets.
-The difference between the two is that one secretes on a surface while the other secretes in a blood stream.
How does the Cell Cycle work?
-The cell cycle works in two ways, either as interphase (nondividing phase) or mitosis (cell division)
-Basically some cells divde every few days and some never do.
-The cycle is not linear as birth --> death
How do exchanges between work organ systems and external environment?
-Glands can excrete towards the external environment
-Mouth can intake food from external environment, goes to digestive system and returns to the external work via waste.
-Water intake from mouth can go into blood and make its way into the urinary system and out into the external world as waste.
-Respiratory system interacts with external environment by gas exchange
-Reproductive system interacts with external world by excreting gametes or intaking gametes
-Integumentary system interacts with external world by protecting us from it.
What are the three major body cavities (or compartments)? What do they contain? How are these comparments helpful and/or counterproductive?
-The three major body cavities are the cranial cavity, thoracic cavity, and abdomino-pelvic cavity.
-Cranial cavity contains...
-Thoracic cavity contains...
- heart enclosed in pericardial sac
- two lungs enclosed in pleural sacs
-Abdominal cavity contains tissue lining called peritoneum that lines all these organs...
-The pelvic cavity contains...
- Reproductive organs
- Urinary bladder
- Terminal portion of large intestine
-Comparments can help separate biochemical processes that might conflict with one other but the barriers between them make it difficult to move much needed materials from one compartment to the other.
What are body compartments seperated by?
-Body compartments are seperated by membranes such as the pericardial sac that surrounds the heart.
What are the fluid body compartments? Define them. Where are they located?
-The fluid body comparments are extracellular fluid, intracellular fluid, blood plasma, and interstitial fluid.
-Extracellular fluid is fluid that lies outside of cells, there is interstitial fluid and blood plasma.
- Interstitial fluid is ECF that surrounds most cells
- Blood plasma is ECF that is inside of blood vessels.
-Intracellular fluid is the fluid that lies inside of cells.
What are the five main types of epithelia in our bodies?
- Thin, flat cells that allow movement through and between cells.
- Protective, stacked layers of cells that are constantly being replaced
- Beating cilia create fluid currents that sweep across epithelial surface
- Make and release a product in the form of exocrine/endocrine secretions.
- Selectively move substances between a lumen and the ECF
What is the cell composed of?
What is the nucleus?
-The nucleus is a structure with an enclosing nuclear envelope that contains the genetic material DNA
What is a gene?
-A length of DNA that codes for a protein.
What is genetic expression?
-Genetic expression is...
- DNA transcribed into mRNA leaves the nucleus.
- mRNA is then translated at ribosome into a specific protein
What is the nuclear envelope? What is its function?
-The nuclear envelope is a double-layed membrane that surronds the nucleus, composed of protein and lipid molecules.
-The nuclear envelope supports the nucleus and controls passage of materials with its inner membrane in and out of the nucleus and cytoplasm. The outer membrane remains continuous with rough ER
What are nucleoli (sing. Nucleolus)? What function do they perform?
-Nucleoli are dense nonmembranous mass composed of protein and RNA molecules.
-Nucleoli control RNA synthesis by production of ribosomal RNA for ribosomes.
What is one crucial step a cell must undergo before dividing itself? What happens during this step?
-The cell must undergo DNA replication in which each DNA molecule replicates itself.
- Complementary nucleotides attach to each exposed strand
-DNA replication is a form of asexual reproduction
What are all the cytoplasmic vesicles? What do they all do?
-There are secretory vesicles, storage vesicles, lysosomes, and peroxisomes.
- Secretory vesicles release waste and material from the cell.
- Storage vesicles hold materials in the cell
- Lysosomes use digestive enzymes to degrade bacteria (foreign molecules) or old organelles
- Peroxisomes oxidize toxic molecules, fatty acids, and some foreign materials (such as alcohol)
-Furthermore... peroxisomes are found mostly in the liver and convert with its enzymes hydrogen peroxide into water and oxygen.
What is a centrosome? What is its function?
-An organelle that has nonmembranous mass of two rodlike centrioles.
-It helps organize spindle fibers and distribute chromosomes during mitosis.
What are vacuoles? What are their functions?
-A vacuole is a membranous sac that store and release various substances within the cytoplasm.
What is Chromatin? What function does it perform?
-Chromatin are fibrous strands composed of protein and DNA.
-Chromatin holds genetic code that determines which proteins (including enzymes) will be manufactured by the cell.
What are microfilaments and microtubles?
-Microfilaments and microtubles are thin, hollow tubes that support cytoplasm and transport materials within cytoplasm.
Where can nervous, muscle, connective, and epithelial tissue be found in the body?
Nervous tissue has two types of cells: neurons or nerve cells which are concentrated in the brain, and glial cells or neuroglia which are the support cells for neurons.
Cardiac muscle has three types: Cardiac which is found in the heart, smooth muscle which makes up most internal organs, and skeletal muscle which attatches to bones and helos with movement.
Connective tissue is most abundunt in the body as it includes the blood, the support tissues for the skin and internal organs, and cartilage and bone.
Epithelial tissue can be found
covering exposed surfaces, such as the skin, and line internal passageways such as the digestive tract.
covering exposed surfaces, such as the skin, and line internal passageways such as the digestive tract.