Summer Studying - Cells Flashcards
What is the Role of a Cell Membrane?
To determine which substances enter and exit and cell (selectively permeable) and harbor biological activity
Describe the Cell Membrane
Thin, flexible, and elastic
What to Membrane Proteins do?
Receive, transport, and determine how a cell will interact with others
Cytoskeleton
Cell skeleton
Endoplasmic Reticulum
also known as ER. a complex organelle whose parts communicate with the cell
membrane and participates in synthesis of protein and lipid molecules
Ribosomes
Sites of protein synthesis. Attached to ER or scattered in cytoplasm. composed of proteins and RNA. provide enzymes.
Golgi Appparatus
composed of abt six flat membranous sacs. refines, packages, and delivers proteins associated with ER. Innermost end is specialized to receive glycoproteins
Mitochondria
powerhouse of the cell. reproduce by dividing. major sites of chemical reactions that transform atp to a form cells can use.
Lysosomes
Garbage disposals of the cell. contain enzymes to break down nutrient molecules.
Peroxisomes
abundant in liver and kidney cells. house enzymes that catalyze biochemical reactions like fat digestion and detoxification of hydrogen peroxide
Microfilaments
provide cell mobility which can help cells contract
Microtubules
composed of globular tubulin proteins arrayed in 9 + 2 pattern. (nine outside tubules form a ring around inside 2)
Centrosome
during mitosis distribute chromosomes to newly forming cells
Cilia
Also 9 + 2. beat in succession to create waves of motion to move fluids across surfaces of tissues
Flagella
undulating wave motion beginning at their base. movement like swimming
Cell Nucleus
houses genetic material (DNA). directs cell activity. enclosed in double layered nuclear envelope.
Nucleolus
(little nucleus)
Chromatin
contains loosely coiled fibers of dna and protein called chromosomes
Diffusion
molecules or ions scatter to lower concentration areas.
can occur when a cell membrane is permeable to the substance or a concentration gradient exists
Facilitated Diffusion
the passive movement of molecules along the concentration gradient. It is a selective process
Osmosis
occurs when water molecules diffuse from a region of higher water concentration to a region of lower across selectively permeable membrane.
Isotonic
any solution that has the same osmotic pressure as body fluids
Hypertonic
solutions with higher osmotic pressure than body fluids
Filtration
forces molecules through membranes. separates solids from waters.
Active Transport
moves particles through membranes from regions of lower concentration to regions of higher concentration.
Endocytosis
molecules or other particles too large to enter a cell by diffusion, facilitated diffusion or active transport are conveyed within vesicles formed from a section of cell membrane.
occurs in three forms : pinocytosis, phagocytosis, and receptor mediated endocytosis
exocytosis
secretes a substance stored in a vesicle of a cell (opposite of endocytosis)
Pinocytosis
“cell drinking”
cells take tiny drops of liquid from surroundings as a portion of cell membrane ingredients
Phagocytosis
“cell eating”
takes in solids rather than liquids.
Receptor-Mediated Endocytosis
moves specific kinds of particles into the cell by binding them first.
What is the Cell Cycle?
The series of changes a cell undergoes from the time it forms until it divides.
Interphase
A cell growing and duplicating its contents before it can actively divide and two cells can form from one
maintains routine and has housekeeping functions. duplicates membranes, ribosomes, lysosomes and mitochondria
replicating it’s genetic material so two new cells will have complete genetic instructions
Mitosis
division of the nucleus
each cell must have complete accurate copy of info to survive
cyrokinesis
division of the cytoplasm
What are the “stages” of Mitosis
Prophase, Metaphase, Anaphase, and Telophase
Prophase
chromosomes become visible in nucleus. each prophase chromosome is composed of two identical portions (chromatids)
centrioles replicate just before mitosis begins
two newly formed centriole pairs move to opposite ends of the cell, nuclear envelope and nucleolus break up, disperse and are no longer visible
Metaphase
chromosomes line up midway between centrioles due to microtubule activity. spindle fibers attach to centromeres
Anaphase
centromeres are pulled apart. chromatids become individual chromosomes that move in oppo directions
Telophase
chromosomes complete migration to centrioles. prophase in reverse. chromosomes unwind into chromatin and nuclear envelope forms. nucleoli appear within new nuclei
Cytoplasm Division
begins during anaphase. membrane constricts down middle of cell. continues through telophase. new cells have identical genetic info
Cell Differentiation
cells develops different characteristics in structure and function. do this by expressing some of the DNA info and repressing other info
Cell Death
Cells that do not divide or specialize may die
Apoptosis
form of cell death sculpting organs from overgrown tissues. carves away webbing between growing fingers and toes in a growing fetus and removes extra brain cells. Also can appear as the peeling of a sun burn.
