Unit 4 Cell structure and transport Flashcards
cell theory
All life is composed of at least one cell
Cells are the basic units of living organisms. Structures (organelles) that compose cells are not considered alive
Cells develop only from pre-existing cells
Prokaryote
Bacteria and Archae are prokaryotes
Lack a nucleus or membrane-bound organelles
eukaryote
All forms of life with the exception of Bacteria and Archae
Contain a nucleus and membrane bound organelles
endosymbiotic theory
mitochondria and chlorplasts used to be their own prokaryotic microbe before; may have combined with eukaryotic cells; this is thought because mitochondria and chloroplasts have their own DNA separate from the organisms
Plant cells vs animal cells
Plant: chloroplasts, cell wall, central vacuole
Animal: centriole, cilia and flagellum
cell wall
only in plant cells; nonliving and helps protect and support the cell; made of cellulose and it is semipermeable
cell membrane
controls what comes in and out of the cell; prevents harmful materials from entering the cell
nucleus
controls all of the cells activities and stores DNA
nucleolus
small organelle inside the nucleus that makes ribosomes
nuclear envelope
the membrane that surronds the nucleus
chromatin
thin strands in the nucleus that contain genetic material
cytoplasm/cytosol
the region on the inside of the cell; gelatinous fluid
mitochondria
the “powerhouse” of the cell; they make energy that the cells can use; has its own unique DNA
smooth endoplasmic reticulum
synthesize lipids like cholesterol and fats and metabolize carbs
rough endoplasmic reticulum
primary site of protein synthesis; once protein synthesis is complete it folds and modifies the proteins; ribosomes attach to its surface to help in synthesizing proteins
Golgi Apparatus
Modifies, sorts, and packages proteins and lipids for storage or transport out of the cell
lysosomes
Contains digestive enzymes to break down waste material, old cell parts, and foreign invaders
centriole
Involved in cell division (mitosis)
Organize the microtubules of the cytoskeleton
centrosome
an organelle that consists of centrioles;
vacuole
the storage area of cells; they store food and materials the cell needs; plants usually have one large vacuole and in animal cells they are smaller and less prominent
vesicle
a sac that is used to transport materials in and out of the cell (endocytosis and exocytosis)
phospholipid bilayer
this is what makes up the cell membranes in eukaryotes; composed of a hydrophilic head that faces toward the extracellular fluid; hydrophobic tail lines the inside of the bilayer
passive transport
doesn’t require energy to move substances across the cell membrane; moves with the concentration gradient (high concentration to low concentration);
diffusion
a method of passive transport; small and non-polar molecules; materials can just move across the membrane with no assistance
facilitated diffusion
molecules need a transport protein to help them go through the membrane; transports larger molecules;
osmosis
passive transport; the transport of water molecules
concentration gradient
The difference in concentration from inside a cell to outside of a cell
Substances move down the concentration gradient from high to low
active transport
it requires energy; moves agaisnt the concentration gradient (low concentration to a high concentration); they use carrier proteins to carry materials
endocytosis
method of active transport; a cell takes in substances from its surrounding environment by engulfing them within a small pocket of the cell membrane, which then pinches off to form a vesicle inside the cell; materials float around in the cell within a vesicle
exocytosis
a cellular process where a cell releases substances stored within vesicles by fusing the vesicle membrane with the cell membrane,
hypotonic
The concentration of solutes is LOWER OUTSIDE of the cell(extracellular fluid/environment) then inside the cell (cytoplasm)
cytolysis
when there is an influx of water into the cell which causes it to burt
hypertonic
The concentration of solutes is HIGHER OUTSIDE of the cell(extracellular fluid/environment) then inside the cell (cytoplasm)
plasmolysis
when there is a shortage of water in the cell causing it to shrivel up
turgor pressure
only in plant cells; the force against a cell wall from the influx of water; a high turgor pressure makes the plant look healthy
