CHAP 3

Flashcards on Cellular Organization

Cells

Building blocks of all plants and animals

New cells

Come from division of preexisting cells

Cells are the smallest living units that

Perform all viral physiological functions

Each cell

Maintains homeostasis at the cellular level

Fertilized ovum, or zygote

Contains genetic potential to become any cell

Cellular differentiation

Process of gradual specialization of cells

Extracellular fluid

Watery medium surrounding cells

Intracellular fluid or cytosol

Fluid inside the cell

Cell plasma membrane

Separates cell contents from extracellular fluid

Cytoplasm

Material between cell membrane and nuclear membrane

Cytosol

Fluid part of cytoplasm

Organelles

Intracellular structures with specific functions

Peroxisome

Vesicles containing degradative enzymes, break down organic and toxic compounds

Lysosome

Vesicles containing digestive enzymes, break down organic compounds

Microvilli

Membrane extensions containing microfilaments, increase surface area for absorption

Golgi apparatus

Stacks of flattened membranes containing chambers, store, alter and package synthesized products

Nucleus

Fluid nucleoplasm, controls metabolism, stores genetic information, controls protein synthesis

Endoplasmic reticulum (ER)

Network of membranous sheets and channels, synthesizes secretory products, detoxifies drugs and toxins

Smooth ER

Synthesizes lipids and carbohydrates

Rough ER

Modifies/packages newly synthesized proteins

Ribosomes

Synthesize proteins

Mitochondrion

Double membrane, produces 95 percent of cellular ATP

Cytoskeleton

Proteins organized into fine filaments or slender tubes, strengthens and supports cell

Plasma membrane

Selectively permeable barrier separating inside of cell from extracellular fluid

Glycocalyx

Layer formed by superficial membrane carbohydrates

Cholesterol

Stiffens the plasma membrane

Integral proteins

Part of the cell membrane and cannot be removed without damaging the cell

Peripheral proteins

Attached to the cell membrane inner or outer surface and are easily removable

Cytoskeleton

Provides internal protein framework

Microfilaments

< 6 nm in diameter, composed of actin, commonly at periphery of cell

Microvilli

Enhance surface area of cell for absorption

Intermediate filaments

7-11 nm in diameter, strongest and most durable cytoskeletal elements

Microtubules

~25 nm in diameter, hollow tubes built from globular protein tubulin

Centrioles

Controls movement of DNA strands during cell division

Cilia

Long, slender plasma membrane extensions, motile cilia common in respiratory and reproductive tracts

Flagella

Longer than cilia and beat in a wavelike fashion

Ribosomes

Responsible for protein synthesis

Endoplasmic reticulum (ER)

Network of intracellular membranes continuous with nuclear envelope, synthesizes and stores proteins, lipids, and carbohydrates

Smooth ER (SER)

Lacks ribosomes, cisternae are often tubular

Rough ER (RER)

Has attached (fixed) ribosomes, modifies newly synthesized proteins

Golgi apparatus

Renews or modifies plasma membrane

Lysosomes

Contain digestive enzymes for intracellular use

Mitochondria

Produce energy (ATP) for cells

Mitochondrial double membrane

Outer membrane surrounds organelle, inner membrane contains folds called cristae

Aerobic metabolism or cellular respiration

ATP production that requires oxygen

Nucleus

Control center for cellular operations, genetic information coded in sequence of nucleotides

Nuclear envelope

Separates nucleus from cytoplasm, double membrane

Nuclear pores

Passageways that allow chemical communication between nucleus and cytoplasm

Nucleoplasm

Fluid contents of nucleus

Nucleoli

Transient nuclear organelles, assemble RNA subunits

DNA in the Nucleus

Stores instructions for protein synthesis

DNA

Long parallel chains of nucleotides

Gene

Functional unit of heredity

Transcription

Takes place in the Nucleus and is the production of RNA from DNA template

Beginning of Assembly

RNA polymerase binds to promoter and begins assembly of mRNA strand

Translation

Formation of a linear chain of amino acids from an mRNA strand

Permeability

Property determining which substances can enter or leave cytoplasm

Diffusion

Net movement of a substance from higher concentration to lower concentration

Osmosis

Net diffusion of water across a membrane

Isotonic

Solution that does not cause osmotic flow across the membrane

Hypotonic

Causes osmotic flow into cell

Hypertonic

Causes osmotic flow out of cell

Carrier Proteins

Transport hydrophilic or large molecules across the cell membrane

Endocytosis

Importing extracellular substances into vesicles called endosomes

Exocytosis

Movement of wastes or secretory products from intracellular vesicle to outside the cell

Vesicular Transport

Materials move across the cell membrane in small membranous sacs called vesicles

Cell Division

Form of cellular reproduction which is responsible for initial increase in cell number

Apoptosis

Genetically controlled death

Mitosis

Produces 2 daughter cells each with 46 chromosomes

Meiosis

Produces sex cells each with only 23 chromosomes

Mitosis

Form of cellular reproduction which division of single cell produces pair of daughter cells

Interphase

Nondividing period where the cell performs normal activities

Cytokinesis

Division of the cytoplasm

Cancer

Illness that disrupts normal rates of cell division with permanent DNA sequence changes (mutations)

Tumor (Neoplasm)

Mass or swelling produced by abnormal cell growth and division

Benign Tumor

Cell remains within original tissue and is seldom a threat

Malignant Tumor

Cells divide rapidly and stimulate blood vessel growth (angiogenesis) to tumor area

Metastasis

Cells migrates to other areas and establish new tumors