Chap 3-Cells And Tissues Flashcards Preview

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Flashcards in Chap 3-Cells And Tissues Deck (47):
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Plasma membrane

Defines the limits of the cell
Acts as a selectively permeable membrane that regulates the entry and exit of the cell materials

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Nucleus

Gene containing control center that houses DNA
Directs all cellular activity

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Cytoplasm

Site of most cellular activities
Contains organelles and inclusions

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Nuclear Envelope (Nuclear Membrane)

Defines the limits of the nucleus
Acts as a selectively permeable membrane that regulates the entry and exit of substances

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Nucleolus

Site where ribosomes are assembled prior to migration into the cytoplasm

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Chromatin

Contains genetic material (DNA)
Forms the chromosomes during mitosis

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Lipid molecules (phospholipids)

Provide the medium in which protein molecules float
Form the basic fabric of the membrane
Relatively impermeable to most water-soluble molecules

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Cholesterol Molecules

Have a stabilizing effect and help keep the membrane fluid

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Protein Molecules

Responsible for most of the specialized functions of the membrane
Act as enzymes
Serve as receptors or binding sites for hormones or other chemical messengers
Act as carriers that bind to substances and move them through the cell membrane
Form pores through which water and small molecules can move

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Carbohydrate Molecules

Add an identification tag to mark protein molecules
Makes the cell membrane a fuzzy, sticky sugar-rich area

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Glycoprotein Molecule

Determine blood type
Act as receptors that certain bacteria, viruses or their toxins can bind to
Play a role in cell-to-cell interactions

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Cytosol

Semitransparent fluid which is largely water, containing dissolved nutrients and a variety of other solutes

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Organelles

Literally the "little organs", specialized cellular compartments, within the cytosol

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Inclusions

Chemical substances dispersed in the cytoplasm that may or may not be present, depending on specific cell type
Most are stored nutrients or cell products

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Centrosome

Composed of 2 rod-shaped bodies that lie at right angles to each other
Internally made up of fine microtubing

Directs formation of the mitotic spindle during cell division

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Cilia

Whip-like cellular extensions

Move substances along cell surface

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Flagella

Projections that are substantially longer than cilia

Propel the cell itself; found in sperm as a single propulsive flagellum

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Lysosomes

Membranous sacs

Contain enzymes that digest worn cellular parts or substances that enter cells

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Ribosomes

Tiny, round, dark bodies floating free in cytoplasm or attached to the endoplasmic reticulum
Made of protein and ribosomal RNA

Synthesize protein

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Endoplasmic Reticulum (ER)

A system of fluid-filled canals (cisterns) coiling and twisting through the cytoplasm

Serves as a mini circulatory system for the cell, providing a network of channels for carrying substances from one part of the cell to another

Rough ER - studded with ribosomes

Transports proteins made on the ribosomes; synthesizes membrane lipids

Smooth ER - continuation of the rough ER

Cholesterol synthesis and breakdown; fat metabolism; detoxification of drugs

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Golgi Apparatus

Stack of flattened membranous sacs associated with swarms of tiny vesicles
Found close to the nucleus

Modifies and packages proteins sent to it by the rough E/R (via transport vesicles)

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Nucleus

Sphere-shaped structure usually located near the center of the cell

Gene containing control center that houses DNA; directs all cellular activities

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Secretory Vesicles

Contain protein tagged for export (Golgi apparatus forms sacs that swell and then pinch off and form secretory vesicles; vesicles travel to and fuse with plasma membrane, membrane ruptures and the contents are expelled to the outside of the cell)

Package proteins like mucus and digestive enzymes for release from the cell

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Transport vesicles

Round membranous sacs

Transport proteins to the Golgi apparatus for packaging

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Peroxisomes

Membranous sacs that look like small lysosomes
Contain powerful oxidase enzymes

Detoxify a number of harmful or poisonous substances; convert free radicals to hydrogen peroxide which is then converted to water by the contained enzyme, catalase

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Mitochondria

Tiny thread-like or sausage-shaped structured that change shape continuously

Cellular respiration

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Cristae

Shelf like protrusions of the inner membrane of the mitochondria

Contain enzymes that are needed in cellular respiration

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Cytoskeleton

Elaborate network of protein structures extending throughout the cytoplasm

Furnishes an internal framework that determines cell shape; supports other organelles; provides machinery for intracellular transport and various types of cellular movement

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Intermediate filaments

Strong stable filaments

Help form desmosomes; provide internal guy wires to resist pulling forces of the cell

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Microtubules

Tubelike

Determine overall shape of a cell and distribution of organelles; important during cell division

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Passive transport

Substances are transported across the membrane without any energy input from the cell; two types are diffusion and filtration

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Diffusion

Process by which molecules and ions tend to scatter through the available space moving from an area of greater concentration to an area of lesser concentration

3 types are simple, osmosis and facilitated

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Simple diffusion

Diffusion of certain solutes like fat soluble molecules that directly diffuse through the bilipid layer of the plasma membrane and solutes smaller than the membrane's pores that diffuse through these pores

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Osmosis

Diffusion of water through a selectively permeable membrane from a region of it's greater concentration to a region of it's lesser concentration

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Facilitated Diffusion

Diffusion that moves large lipid insoluble molecules across the membrane - the transported substance is bonded to a carrier molecule

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Filtration

Movement of substances through a membrane from an area of higher hydrostatic pressure to an area of lower hydrostatic pressure

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Active transport

Process in which a cell uses energy from its ATP to move substances across the membrane; two types are solute pumping and bulk transport

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Solute pumping

Substances are moved across the membrane by proteins against a concentration gradient

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Bulk transport

Transport of large molecules that can't get through the plasma membrane in any other way. They are enclosed in vesicles that pinch off the cell membrane and are transported either out or into the cell

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Exocytosis

Type of bulk transport that moves substances out of the cell. The product is packaged into a small membranous sac which migrates to the plasma membrane and fuses with it. The fused area then ruptures, spilling it's contents out of the cell

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Endocytosis

Type of bulk transport in which extracellular substances are taken into the cell by vesicles formed from an inward folding of the plasma membrane

2 types are phagocytosis and pinocytosis

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Phagocytosis

Uptake of large solid particles

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Pinocytosis

Uptake of fluids that have dissolved proteins or fats

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Prophase

Stage 1 of mitosis

Chromosomes - chromatin threads coil and shorten so that visible bar like bodies appear in no regular arrangement

Chromatids - each chromosome is made up of two strands called chromatids which are held together by a centromere

Mitotic Spindle - centrioles separate and move toward opposite sides of the cell directing the assembly of the mitotic spindle between them as they move

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Metaphase

Stage 2 of mitosis

Chromosomes - cluster and align at center of the spindle, midway between centrioles, forming a straight line

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Anaphase

3 stage of mitosis

Centromeres - split

Chromosomes - move slowly apart toward opposite ends of the cell

Cleavage Furrow - marks the beginning of the second event of cell division, cytokinesis. Furrow appears over the midline of the spindle and will eventually pinch the cytoplasmic mass into two parts

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Telophase

4th stage of mitosis

Chromosomes - opposite ends of cell; uncoil and become chromatin

Mitotic spindle - breaks down and disappears

Nuclear membrane - forms around each chromatin mass

Nucleoli - appear in each daughter nuclei

Cleavage furrow - cytokinesis produces 2 separate daughter cells