The cell Flashcards
Define the cell”
structural units of all living things
How many cells in human body/
50 to 100 trillion
4 concepts of cell theory
- A cell is the basic structural and functional unit of living organisms.
- The activity of an organism depends on the collective activities of its cells.
- According to the principle of complementarity, the biochemical activities of cells are dictated by the relative number of their specific subcellular structures (function is dependent on structure, and that the form of a structure relates to its function)
- Continuity of life has a cellular basis.
chemical components of cells
- carbon
- hydrogen
- oxygen
- nitrogen
Cells are about __% water
60
3 major region/ parts of a cell
- nucleus
- cytoplasm
- plasma membrane
What is the nucleus?
control center of the cell (contains deoxyribonucleic acid (DNA))
What is DNA needed for
building proteins and cell production
What is DNA needed for
building proteins and cell production
What are organelles?
specialized cellular compartments
many r membrane bound
compaertmentalization is critical for organelle’s ability to perform specialized function
Mitochondria function
powerhouse of cell
carry out reaction where oxygen is used to break down food
provides ATP for cellular energy
What does Mitochondria look like?
changes shape continuously
consists of a double membrane with cristae on the inner membrane
What are ribosomes?
made of protein and ribosomal RNA
sites of protein synthesis
found in cytoplasm and rough ER
What do ribosomes look like?
bi-lobed dark bodies
What is rough er?
studded with ribosomes
synthesizes proteins
transports vesicles more proteins within cells
abundant in cells that make and exports proteins
Smooth ER
functions in lipid metabolism
detoxification of drugs and pesticides
What IS endoplasmic reticulum?
Fluid-filled cisterns (tubules or canals) for carrying substances withing the cell
What is the golgi apparatus?
modifies and packages proteins arriving from the Rough ER via vesicles
produces different types of packages
What type of packages does the golgo apparatus produce?
SECRETORY VESICLES
LYSOSOMES
IN HOUSE PROTEINS AND LUPIDS
What does the golgi apparatus look like?
appears as a stack of flattened membrane associated with tiny vesicles
What are lysosomes?
membranous bags packages by the golgi apparatus
cotains enzymes produced by ribosomes to digest wornout or nonusable cellstructuers
hosts phagocytes that can duspose of bacteria and cell debris
3 types of surface extensions
cilia
flagella
microvilli
what is cilia
move materials across the cell surface - respiratory system to move mucus
flagella
propels the cell - sperm (only flagellated in humans)
microvilli
tiny, fingerlike extensions of the plasma membrane - increase surface area for absorption
cell vary from _______ to over _________ (nerve cells)
1/12,000 of an inch to over 1 yard
cells that connect body parts
fibro blasts - secretes cable-like fibers
erythrocyte (red blood cells) - carries oxygen in blood stream
Cells that cover and line body organs
Epithelial cells - packs together in sheets and resists tearing during rubbing or pulling
Cells that move organs and body parts
skeletal muscles and smooth muscle cells - contractile filaments allow cells to shorten forcefully
Cells that store nutrients
fat cells - lipid droplets stored in cytoplasm
cells that fight disease
macrophage - digests infectious microorganisms
Celsl that gather info and control body functions
Neuron (nerve cells) - receives and transmits messages to other body structures
Cells of reproduction
oocyte - largest cell in body, divides to become embryo upon fertilization
Sperm - built for swimming to egg for fertilization, flagellum acts a motile whip
What does the plasma (cell) membrane do
seperates cell contents from surrounding environment
What is the fluid mosaic model constructed of
- Phospholipids
- Cholesterol
- Proteins
- Sugars
Arrangements of phospholipids in plasma membrane
hydrophiliac polar heads r oriented on the inner and outer surfaces of the mebrane &
hydrophobic nonpolar tails from the center (interior) of the membrane - makes plasma membrane impermeable to most water solubles
3 roles/ types of proteins you would find in the plasma membrane
- enzymes
- receptors
- Transport as channels or carriers
What are the 2 types of membrane transport?
- Passive processes - no energy (ATP) needed
2. Active processes - cells must provide ATP
What is diffusion?
particles distribute themselves evenly using primarily kinetic energy )molecules move random) from high to low conentrations
What affects the speed of diffusion
size and temp affect speed of diffusion (smaller and warmer = faster)
Examples of diffusion
if you pout a cup of coffee and add sugar, even if you do not stir it the coffee will taste sweet
What is simple diffusion
unassisted process
soultes are lipid-soluble or small enough to pass through membrane pores
What is osmosis?
Simple water diffusion where highly polar water easily crosses the plasma mebrane with the concentration gradient
What is osmosis?
Simple water diffusion where highly polar water easily crosses the plasma mebrane with the concentration gradient
Isotonic solutions
same solute and water concentration within and outside of cells
Hypertonic solutions
contain more solute than cels so cells shrink (water goes out)
Hypotonic solution
contains fewer solution (more water) than cells so cells will take in water (plump)
What is facilitated diffusion
transports lipid-insoluble and large substances such as glucose through protein membrane channels or protein molecules that act as carriers
What is filtration
water and solutes are forced through a membrane by fluid or hydrostatic pressure (pressure must exist) from high pressure to low pressure
What is filtration critical for/
the kidney to function
What is active processes?
requires protein carries to transport substances that r too large for membrane channels, r not lipid-soluble, o r are agaisn t the concentration gradients using ATP
Solute pumping
energized by ATP to move amino acids, some sugars and ions through a protein carries called solute pump against conentration or electrical gradients
What is an exampel of solute pumping?
3 sodium in transported out of the cell in exhcange for 2 potassium tranported into cell
What is vesicular transport?
the movement of substances without crossing the plasma membrane
What are examples of vesicular transport?
exocytosis and endocytosis (phagocytosis and pinocytosis)
What is exocytosis
Moves materials out of the cell using a vesicle that migrates to the plasma mebrane before combining with it and emptying the material outside the cell
What is the exoctoysis docking process
transmembrane proteins on the vesicles called v-SNARES binds with plasma membrane proteins called t-SNARES
What is Phagocytosis
cell eating - separates substances from external environment using pseudopods before the cell engulfs large particles like bacteria or dead body cells as a protective mechanisms
What is pinocytosis?
cell drinking - the cell gulps droplet of extracellular fluid containing dissolves proteins or fats before fusing with the pit created by the plasma membrane and expelling it
What cell is pinocytosis routine for
those involved in absorption (small intestine)
