Unit 3 Cellular level (Human Anatomy & Physiology)

4 principle parts of animal cell

nucleus

cytosol

organells

cell membrane

nucleus

• control center of cell

• largest structure within cell

• dna

• controls cell function and structure

  • nucleolus, DNA, RNA, chromosomes, chromatin, genes

cytosol

• semi-fluids portion of cytoplasm

• mostly water

• function site of chemical reactions

• contains cellular organelles, proteins, and carbohydrates

organelles

• permanent “little organs” found within cytosol

• highly specialized structures that preform different roles

cell membrane

• protective barrier that exits on the perimeter of cell to maintain homeostasis

• selective permeability

structure of cell membrane

a flexible outer shell of cell that regulates the concentration of substances inside the cell

phospholipid bilayer

• cell membrane is composed of a phospholipid bilayer or two layers of phospholipids

• fatty acids with a phosphate group attached to them

• molecule has heads that face outward while tails face inward (creates a polar hydrophilic head and non-polar hydrophobic tail.

integral protein

extend into and sometimes completely through the membrane and act as channels, gates, or carrier proteins.

• 3 categories

  • marker protiens

  • transport protiens

  • receptor protiens

peripheral protiens

• loosely bound on inside or outside

• acts as structural proteins and cell identity markers

cholestorol

• lipid produced by liver

• gives membrane strength

• helps prevent fatty acids tails from sticking to each other which would collapse the membrane

carbohydrates

chains extend from the surface of the cell membranes and help in cell identification. (glycolipids (sugar attached to lipids) and glycoprotein(sugary protein) )

selectivly permeable

ability of cell membrane to allow certain substances to enter or exit the cell while not permitting others to do the same, it is required to maintain cells homeostasis

2 structures in cell membrane that allows it to be selectively permeable

carbohydrates

integral protein

factors that influence permeability

• molecule size

• solubility in lipids

• charge on ions

• presence of carrier proteins

intracellular fluid (ICF)

• location

  • found in living cells

• composition

  • contains large amounts of potassium, phosphate, 2/3 of body’s total water

extracellular fluid (ECF)

• location

  • found between the cells, plasma, lymph, cerebrospinal fluid, synovial fluid, serous fluid, aqueous humor and endolymoh

• composition

  • 1/3 of body’s total water

cilia

tiny, hairlike structures in cell membrane that are coupled with the cytoskeleton. Their main purpose is to help move cell (synchronized swimmer)

flagellum

slender, threadlike, structure that is coupled with the cytoskeleton that helps the sperm cell swim. Sperm cell in only cell that contains a flagellum because its the only cell that requires propulsion (speed swimmer)

passive transport process

• no energy

• high to low concentration

diffusion

• movement of molecules from high to low concentration until molecules are evenly distributed, may occur through water or air.

  • ex; spraying perfume and eventually everyone in room can smell it

osmosis

• movment of water molecules through a semipermeable membrane down a concentration gradient of high to low concentration

• -occurs when imbalance sulutes outside of cell vs inside

• the passing of water through a semipermeable membrane creates a pressure called osmotic pressure

facilitated diffusion

movement of molecules from high to low concentration using proteins in a cell membrane as carriers of molecules to transport them through the cell membrane

filtration

process of removing particles from a solution by allowing the liquid to pass through a membrane. It is controlled and influenced by gravity or hydrostatic pressure.

dialysis

the separation of smaller molecules from larger molecules during diffusion through a semipermeable membrane. The separation occurs because of the different diffusion rates of the smaller molecules vs larger,

active transport process

• requires energy

• low to high concentration

• may utalize 40% of cells ATP supply

endocytosis

molecules are too big to enter a cell by diffusion or active transport, they met be transported within a vehicle formed by the cell membrane

phagocytosis

cell eating occurs when a portion of the cell membrane pinches off around solid material forming a sac-like structure called a vehicle, the vesicle moves into interior of cell, the membrane breakes it down, and the solid particle is now inside the cell. This is how many white blood cells work to fight infection.

exocytosis

any remaining particles from phagocytosis may be expelled from the cell when a vesicle joins with the cell membrane and the contents are moved out of the cell.

sodium potassium pump

cell transports potassium into the cell while transporting sodium out of the cell in an effort to maintain the ion concentration needed for action potentials or nerve impulse transmissions to occur. Happens in the refractory period during the action potential

isotonic solution

solution containing same concentration of dissolved substances and water as the living cell placed in it.

• since concentration of water is the same on both sides of the cell membrane, equal amounts of water enter the cell as exit the cell.

  • ex; blood cells will stay the same size when placed in an isotonic solution

hypotonic solution

a solution containing a lower concentration of dissolved substances and a greater concentration of water than found in the cell

• since concentration of water is higher outside cell membrane than inside the cell membrane, there is a net movement of water into the cell by osmosis. This causes the cell to swell

  • ex: blood cells are blacked in distilled water, the blood cells would swell and burst in a a process called hemolysis

hypertonic solution

water moves out of the cell, more water in cell than cell membrane, cell shrinks

• 
  

  • ex; if a person’s boat sinks at sea, he cannot drink the salty sea water or massive dehydration and shrinking of the body cells would result

organelles characteristics

growth

repair

maintence

control of cellular functions

nucleolus

site of ribosome production (rRNA) ribosome factory

DNA

double strand helix of genetic material inside nucleus

RNA

single strand helix of genetic material produced in the nucleus and exists through nuclear pores (mRNA, tRNA, rRNA)

gene

segment of DNA that codes for a protein

chromatin

thread-like, loosely coiled dna

chromosomes

tightly packed DNA prior to cell devision

ribosome

• made in nucleolus,

• small, round, granular structures

• sites of protein synthesis by assembling amino acids in order, made up of special RNA

Endoplasmic reticulum

double membrane channels which are continuos with the nuclear membrane

Smooth ER

free of ribosomes

rough Er

studded w/ribosomes

golgi complex

• processes, packages, sports and delivers protiens to cell

• secretion of lipid molecules for transport.

• form lysosomes from trans face

golgo vesivles or vacuoles

-fluid and product filled organnels enclosed by a lipid bylarey

-varied storage functions are for metabolism transport, enzymes and chemical RNA

-vesicles are smaller than vacules and cdan fuse to other cells

lysosome

small membrane enclosed sphere or digestive enzymes. Intercellular digestion,

autophasy is process by old worn out organells digested

autolysis is process by which lysosome digest themselves

peroxisome

found in liver&kidney, must have metabolic oxygen to function, detoxifying molecules break down fatty acids through beta oxidation

mitochondrea

powerhouse of cell, small spherical or rod shaped,

structures, sites of cellular respiration…conversion of glucose & lipids to ATP, aerobic energy metabolism, Krebs cycle

cytoskeleton

internal structure of cytoplasm

provides support&mains shape of cell, organization for chemical reactions, assists in transport of substances through cytosol

microfilaments

rod-like, variable length- acting & myosin in muscles

microtubles

straight cylindrical structures

intermediate filaments

strucctural support & framework

centrosomes

dense area of spherical cytoplasm generally located near the nucleus

centrioles

dense area of spherical structures located within the centrosome which serves as center of chromosome movement during cell devision

micovilli

folds on cell membrane, increase surface area for absorption of nutrients, digestive system

cilia

slender projections of cell membrane, move substances across surface of cell,

label the cell

cell division

cell reproduce themselves in increased number of cells or hyperplasia. Body cells/somatic cells have 46 chromosomes in every cell. Sex cells or gametes have 23 chromosomes in every cell .

step one: nuclear division

• (mitosis)-46 chromosomes

• (meiosis)-23 chromosomes

interphase, metabolic phase

• replication of DNA molecules go from 46 to 92

• replication of centrioles

• time-highly variable from non existent to years

• nromaly 18-24 hours

mitosis

formation of new daughter cells with identical genetic makeup of the parent cell, called diploid (2n)

meiosis

mechanism which sperm and egg cells are produced, called gametes

fertilization

union and fusion or gametes

zygote

cell produced by fetrilization

mitosis and cytokinesis stages

PMAT

• prophase =dna is tightly packed, nuclear membrane disapears

• Metaphase=chromosomes line Iine up in middle

• anaphase=chromosomes break apart and move to opposite sides

• telophase=2 nuclei and nuclear membrane reappears in each cell.

Meiosis process

the gametes ungergo one more round of cell division to create 4 new non identical haploid cells