Ch 3 Summary

cells

highly organized units containing organelles, which perform specific functions

nucleus

contains genetic material

cytoplasm

living material between the nucleus and cell membrane

life

cell are the basic unit of . . .

functions of cell

what are the following functions, functions of ?

protect and support the body

cell metabolism

communication

inheritance

cell membrane

forms the outer boundary of cell (determining what goes in and out of cell), composed of a double layer of phospholipid molecules where proteins float

types of passive membrane transport

simple diffusion, osmosis, facilitated difusion, and filtrationd

doesn’t require energy

does passive transport require or doesn’t require energy (atp)

diffusion

movement of solute from area of higher concentration to an area of lower concentration within solvent

concentration gradient

solute concentration difference between two points divided by the distance between points

lipid soluble molecules

able to pass through cell membranes readily by dissolving in lipid portion of membrane

osmosis

diffusion of water across a selectively permeable membrane

osmotic pressure

force require to prevent movement of water across a selectively permeable membrane

hypotonic solution

cells swell and can undergo lysis

isotonic solution

cells neither swell nor shrink

hypertonic solution

cell shrink and undergo crenation

facilitated diffusion

mediated transport process that moves substances from a higher to lower concentration and does not require energy in form of ATP

active transport

can move substances from a lower to higer concentration and requires ATP

secondary active transport

uses energy of one substance moving down its concentration gradient to move another substance across cell membrane

endocytosis

movement of materials into cells by formation of vessicle

receptro mediated endocytosis

involved cell receptors attaching to molecules which are then transported out of cell

phagocytosis

movement of solid material into cells

pinocytosis

similar to phagocytosis, except that material ingested is much small and is in solution

exocystosis

secretion of materials from cells by vesicle formation

nucleus envelope

consists of two separate membranes that form nuclear pores at many points on the surface of nucleus

chromatin

what are the DNA and associated proteins found inside nucleus called ?

DNA

hereditary material of cell and control cell activities

nucleoli

consist of RNA and proteins and are sites of ribosomal subunit assembly

ribosomes

sites of protein synthesis, composed of one large and one small subunit

rough ER

endoplasmic reticulum (ER) with ribosomes attached, major site of protein synthesis

smooth ER

endoplasmic reticulum (ER) that doesn’t have ribosomes attached and is major site of lipid synthesis

golgi apparatus

series of closely packed membrane sacs that collect, modify, package, and distribute proteins and lipids produced by ER

secretory vesicles

membrane bound sacs containing enzymes

lysosomes

within a cell, these break down phagocytized material

peroxisomes

break down fatty acids, amino acids, and hydrogen peroxide

mitochrondia

major site for production of ATP, which cells use as an energy source, carry out aerobic respiration

cytoskeleton

supports the cytoplasm and organelles and is involved with cell movements; composed of microtubules, microfilaments, and intermediate filaments

centrioles

located in centrosome, made up of microtubules, and facilitate chromosome movement during cell division

cilia

move substances over the surface of cells

flagella

much longer than cilia and propel sperm cells

microvilli

increase the surface area of cells and thus aid in absorption

enzymes

what is cell activity regulated by

DNA

what controls enzyme production

transcription

where a sequence of nucleotides in DNA determines the sequence of nucleotides in mRNA, then mRNA moves through nuclear pores to ribosomes

codons

three nucleotide sequences in mRNA that specify a particular amino acid

cell cycle

consists of series of events that produce new cells for growth and tissue repair

interphase and cell division

what are the two phases of cell cycle

S phase

when does DNA replicate during interphase

mitosis

what cell division occurs through, divided into four divisions

prophase

each chromosome consists of two chromatids joined at the centromere

metaphase

chromosomes align at the center of cell

anaphase

chromatids separate at the centromere and migrate to opposite poles

telophase

two new nuclei assume their normal structure and cell division is completed, producing two new daughter cells

differentiation

process by which cells develop specialized structures and functions, results from selective activation and inactivation of DNA sections

apoptosis

programmed cell death, regulates number of cells within various tissues of body