biology notes chapter four complete

7/30/2019 Biology Notes Chapter Four Complete

1/22

Biology Notes 07/12/2009 22:50:00

4.1- Microscopes reveal the world of the cell

Vocabulary-

Light microscope (LM)

o

An optical instrument with lensesthat refract (bend) visible light to

magnify images and project them

into a viewer's eye or onto

photographic film.

Cell theory

o The theory that all living things

are composed of cells and that all

cells come from other cells.

Electron microscope

o An instrument that focuses an

electron beam through, or onto

the surface of, a specimen. An

electron microscope achieves a

hundredfold greater resolution

than a light microscope.

Scanning electron microscope

o A microscope that uses an

electron beam to study the

surface architecture of a cell or other specimen. Transmission electron microscope (TEM)

o A microscope that uses an electron beam to study the internal structure of

thinly sectioned specimens.

4.2- Most cells are microscopic

There is a reason that our knowledge of cells depended on the development of

the microscope.

Most cells cannot be seen with the naked eye.

The logistics of carrying out a cells function sets limits on its size

o Minimum: Must be big enough to house DNA, protein molecules, and

internal structures to survive and reproduce

o Maximum: required to have enough surface area to obtain adequate

nutrients and oxygen and dispose of wastes

o Also limited to the distance these materials must diffuse in a cell


2/22

Larger cells have more surface area than smaller cells, but less area in

comparison to their volume than smaller cells

4.3- Prokaryotic cells are structurally simpler than eukaryotic cells

Vocabulary

Prokaryotic cells

o A type of cell lacking a membrane-enclosed nucleus and other membrane-

enclosed organelles; found only in the domains Bacteria and Archaea.

Eukaryotic cells

o A type of cell that has a membrane-enclosed nucleus and other

membrane-enclosed organelles. All organisms except bacteria and

archaea are composed of eukaryotic cells.

Plasma membrane

o The membrane that sets a cell off from its surroundings and acts as a

selective barrier to the passage of ions and molecules into and out of the

cell; consists of a phospholipid bilayer in which are embedded molecules

of protein and cholesterol.

Chromosomes

o A threadlike, gene-carrying structure found in the nucleus of a eukaryotic

cell and most visible during mitosis and meiosis; also, the main gene-

carrying structure of a prokaryotic cell. Chromosomes consist of

chromatin, a combination of DNA and protein.

Ribosomes

o A cell structure consisting of RNA and protein organized into two subunits

and functioning as the site of protein synthesis in the cytoplasm. The

ribosomal subunits are constructed in the nucleolus.

Cytoplasm

o Everything inside a cell between the plasma membrane and the nucleus;

consists of a semifluid medium and organelles.

Nucleoid

o A dense region of DNA in a prokaryotic cell.

Flagella


3/22

o Plural, flagella) A long cellular appendage specialized for locomotion. The

flagella of prokaryotes and eukaryotes differ in both structure and

function. Like cilia, eukaryotic flagella have a 9 + 2 arrangement of

microtubules covered by the cell's plasma membrane.

Two kinds of structurally different cells have evolved over time.

Prokaryotic cells

o Bacteria and archaea

Eukaryotic cells

o Everything else, ie; protists, fungi, plants, and animal

All cells have several basic features in common

Bounded by a plasma membrane

Have chromosomes

o Carry genes of DNA

Contain ribosomes

o Tiny structures that

make proteins according

to gene instruction

Have cytoplasm

o Area between nucleus

and cell membrane

Eukaryotic cells

Membrane bound nucleus

o Houses DNA

Contain many more membrane bound organelles than prokaryotic cells

Usually about 10x the size of prokaryotic cell

Prokaryotic cells


4/22

Nucleoid

o Where DNA is stored in a prokaryotic cells

No membrane surrounds DNA

Ribosomes

o

Smallero Differ

Basis for the action of some antibiotics

Have a rigid, chemically complex cell wall

o Protects and helps maintain shape

Flagella

o Long projections that propel the cell through its liquid environment

4.4- Eukaryotic cells are portioned into functional compartments

Vocabulary

Organelles

o A membrane-enclosed structure with a specialized function within a cell.

Cellular metabolism

o The chemical activities of cells

Plant Cell


5/22


6/22

4.5- The structure of membrane correlates with their function

For all cells, the plasma membrane forms a boundary between the living cell and its

surroundings and controls the traffic materials into and out of the cell.

4.6- The nucleus is the cells genetic control center

Vocabulary

Nucleus


7/22

o (plural, nuclei) (1) An atom's central core, containing protons and

neutrons. (2) The genetic control center of a eukaryotic cell.

Chromatin

o The complex of DNA and proteins that constitutes eukaryotic

chromosomes; often used to refer to the diffuse, very extended formtaken by chromosomes when a cell is not dividing.

Nuclear envelope

o A double membrane, perforated with pores, which encloses the nucleus

and separates it from the rest of the eukaryotic cell.

Nucleolus

o A structure within the nucleus of a eukaryotic cell where ribosomal RNA is

made and assembled with proteins imported from the cytoplasm to make

ribosomal subunits.

The nucleus contains most of the calls DNA and controls the cells activities by

directing protein synthesis

Eukaryotic cells

Made up of chromatin

o A complex of DNA and

protein

o Appears as a diffuse

mass

o As a cell prepares to

divide, the DNA is

copied and the thin

chromatin fibers coil up,

becoming thick enough

to be seen with a light microscope

Nuclear envelope

o Encloses the nucleus

o A double membrane perforated with protein-lined pores

o Control the flow materials into and out of the nucleus

o Connects with the cells network called the endoplasmic reticulum Nucleolus


8/22

o A prominent structure in the nucleus

o A special type of RNA called ribosomal RNA

Synthesized according to instruction in DNA

4.7- Ribosomes make proteins for use in the cell and export

Ribosomes are the cellular components that carry out protein synthesis.

High rated of proteins, means more ribosomes

Ribosomes found in two areas

Free ribosomes- suspended in fluid

Bound ribosomes- attached to the endoplasmic reticulum, and nuclear envelope

Structurally identical, and ribosomes can alternate between the two.

Most proteins made on free ribosomes function with cytoplasm

Ex. Enzymes that catalyze the first steps of sugar breakdown

Cells that specialize in protein secretion, have a high proportion of bound ribosomes

to free ribosomes

4.8- Overview: Many cell organelles are connected through the end membrane

system

Vocabulary

Endomembrane system

o A network of membranes inside and around a eukaryotic cell, related

either through direct physical contact or by the transfer of membranous

vesicles.

Endoplasmic reticulum

o An extensive membranous network in a eukaryotic cell, continuous with

the outer nuclear membrane and composed of ribosome-studded (rough)

and ribosome-free (smooth) regions. See also rough ER; smooth ER.


9/22

4.9- The endoplasmic reticulum is a biosynthetic factory

Vocabulary-

Smooth endoplasmic reticulum

o A network of interconnected membranous tubules in a eukaryotic cell's

cytoplasm. Smooth ER lacks ribosomes.

Rough endoplasmic reticulum

o A network of interconnected membranous sacs in a eukaryotic cell's

cytoplasm. Rough ER membranes are studded with ribosomes that make

membrane proteins and secretory proteins.

Glycoprotein

o A macromolecule consisting of one or more polypeptides linked to short

chains of sugars.

Transport Vesicle

o A tiny membranous sac in a cell's cytoplasm carrying molecules produced

by the cell. The vesicle buds from the endoplasmic reticulum or Golgi and

eventually fuses with another membranous organelle or the plasma

membrane, releasing its contents.

Smooth ER The Smooth ER of various cell types functions in diverse metabolic processes.


10/22

o Enzymes are important in the synthesis of lipids, including oils,

phospholipids and steroids.

Liver

o Certain enzymes in the smooth ER help process drugs and other

potentially harmful substances.o As cells are exposed to chemicals, the amount of smooth ER increases

Store calcium ions

o Muscle cells

o Rush of calcium into cell causes the cell to contract

Rough ER

One of the functions of Rough ER is to make more membrane

o Phospholipids made by enzymes are inserted into membrane

Therefore enlarges

Part of membrane is transferred to other parts of the

endomembrane system by vesicles.

Bound ribosomes produce proteins to be inserted into membrane, used in cell, or

transported out of cell

Protein synthesis


11/22

4.10- The Golgi apparatus finishes, sorts and ships cell products

Vocabulary-

Golgi apparatuso An organelle in eukaryotic cells consisting of stacks of membranous sacs

that modify, store, and ship products of the endoplasmic reticulum.

After leaving the ER, many transport vesicles travel to the Golgi apparatus

Discovered by Camillo Golgi

Flattened sacs on top of each other.


12/22

Cell can contain few, or hundreds

o Depends on how active the cell is in secreting proteins

Functions

Receives and modifies products from ER One side serves as a receiving dock, and vesicles join the Golgi apparatus

Exit from the other side, and travel elsewhere.

Products are usually modified during their transit in the Golgi.

Sacs nature as they move from receiving side to shipping side

Vesicles become part of plasma membrane, or exit from it.

4.11- Lysosomes are digestive compartments within a cell

Vocabulary-

Lysosome

o A digestive organelle in eukaryotic cells; contains hydrolytic enzymes that

digest the cell's food and wastes.

A lysosomes consists of digestive enzymes enclosed in a membranous sac

Enzymes and membranes made by Rough ER and then transported to Golgi for

more processing.

Illustrate compartmentalization

Enclosed a compartment in which digestive enzymes are provided with an acidic

environment and are safely isolated from the rest of the cell

Several digestive functions

Many protists engulf food particles into cytoplasmic sacs called food vacuoles

With help of lysosomes, cell continually renews itself

4.12- Vacuoles function in the general maintenance of the cell

Vocabulary-

Vacuoleso A membrane-enclosed sac that is part of the endomembrane system of a

eukaryotic cell, having diverse functions.

Central Vacuole

o A membrane-enclosed sac occupying most of the interior of a mature

plant cell, having diverse roles in reproduction, growth, and development.


13/22

Vacuoles are membranous sacs that have a variety of functions.

Central vacuole

o Has hydrolytic functions like a lysosomes

o Helps the cell grow in size by absorbing water and enlarging

o

Can store vital chemicals or waste productso

Without a way to get rid of excess water, the cell would become too dilute to support

life, and eventually would swell and burst.

4.13- A review of the structure involved in the manufacturing and breakdown

Vocabulary-

Peroxisome

o An organelle containing

enzymes that transfer

hydrogen from various

substrates to oxygen,

producing and then

degrading hydrogen

peroxide.

Relationships

Structural

o Between

Nuclear envelope

Rough ER

Smooth ER

Functional

o Membrane and proteins produced by the ER travel in transport vesicles to

the Golgi and from there to other areas.


14/22

o Some become lysosomes or vacuoles

Transport vesicles

Carry secretory proteins to the protein membrane

Peroxisome An organelle containing enzymes that transfer hydrogen from various substrates

to oxygen, producing and then degrading hydrogen peroxide.

Not a part of the endomembrane system

Breaks down fatty acids to be used as fuel and detoxify

4.14- Mitochondria harvest chemical energy from bond

Vocabulary-

Mitochondria

o An organelle in eukaryotic cells where cellular respiration occurs. Enclosed

by two concentric membranes, it is where most of the cell's ATP is made.

Intermembrane space

o One of the two fluid-filled internal compartments of the mitochondrion.

The intermembrane space is the narrow region between the inner and

outer membranes.

Mitochondrial matrix

o The fluid contained within the inner membrane of a mitochondrion.

Mitochondria are organelles that carry out cellular respiration in nearly all eukaryotic cells

Convert sugars and foods to ATP (adenine triphosphate)


15/22

o Main source of energy for cellular work

Structure suits function

Two phospholipids bilayers each with unique embedded proteins

Two internal componentso Intermembrane space

The narrow region between the inner and outer membranes.

o Mitochondrial matrix

Enclosed by inner membrane

Contains mitochondrial DNA, and ribosomes

Also includes many enzymes that catalyze some reactions of

cellular respiration

o Inner membrane

Highly folded

Embedded with molecules of protein that make ATP

o Cristae

Folds

4.15- Chloroplasts convert solar energy to chemical energy

Vocabulary-

Chloroplasts


16/22

o An organelle found in plants and photosynthetic protists that absorbs

sunlight and uses it to drive the synthesis of organic molecules (sugars)

from carbon dioxide and water.

Stroma

o

The fluid of the chloroplast surrounding the thylakoid membrane; involvedin the synthesis of organic molecules from carbon dioxide and water;

Sugars are made in the stroma by the enzymes of the Calvin cycle.

Thylakoids

o One of a number of disk-shaped membranous sacs inside a chloroplast.

Thylakoid membranes contain chlorophyll and the enzymes of the light

reactions of photosynthesis. A stack of thylakoids is called a granum.

Granum

o A stack of hollow disks formed of thylakoid membrane in a chloroplast.

Grana are the sites where light energy is trapped by chlorophyll and

converted to chemical energy during the light reactions of photosynthesis.

4.16- Mitochondria and chloroplasts evolved by endosymbiosis

Vocabulary-

Endosymbiosis

o A process by which the mitochondria and chloroplasts of eukaryotic cells

probably evolved from symbiotic associations between small prokaryotic

cells living inside larger cells.

4.17- The cells internal skeleton helps organize its structure and activities

Vocabulary-

Cytoskeleton

o A network of protein fibers in the cytoplasm of a eukaryotic cell; includes

microfilaments, intermediate filaments, and microtubules.

Microfilaments

o The thinnest of the three main kinds of protein fibers making up the

cytoskeleton of a eukaryotic cell; a solid, helical rod composed of the

globular protein actin.


17/22

Intermediate filaments

o An intermediate-sized protein fiber that is one of the three main kinds of

fibers making up the cytoskeleton of eukaryotic cells. Intermediate

filaments are ropelike, made of fibrous proteins.

Microtubuleso The thickest of the three main kinds of fibers making up the cytoskeleton

of a eukaryotic cell; a straight, hollow tube made of globular proteins

called tubulins. Microtubules form the basis of the structure and

movement of cilia and flagella.

4.18- Cilia and flagella move when microtubules bend

Vocabulary-

Cilia

o A short cellular appendage specialized for locomotion formed from a core

of nine outer doublet microtubules and two single microtubules covered by

the cell's plasma membrane.

Basal Body

o A eukaryotic cell organelle consisting of a 9 + 0 arrangement of

microtubule triplets; may organize the microtubule assembly of a cilium or

flagellum; structurally identical to a centriole.

Microtubular structures that extend outside some cells and that assist in moving the

cell or the cell's surroundings.

Flagella are much longer than cilia.

When a cell has cilia, their number is large, whereas a cell will have few flagella,

or a single flagellum.

Many protists have cilia, and the sperm of many plants and animals have flagella.

Flagella and cilia are assembled from tubulin subunits organized to form a circular

arrangement of nine pairs ofmicrotubules attached to a central pair.

Flagella and cilia bend to cause movement of either the cell or the surroundings.

The bending uses energy derived from the hydrolysis ofATP.
http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#http://volumes/CampbellConcepts6/mediaserver/bc/bc_campbell_concepts_6/activities/c6eLib/activities/H07/H0708/st01/gt01.html#


18/22

4.19-Problems with sperm motility may be environmental or genetic

When the flagellum dont flip correctly, the mommy does not get pregnant.

4.20- The extracellular matrix of animal cells functions in support, movement, and

regulation

Vocabulary-

Extracellular matrix

o A substance in which the cells of an animal tissue are embedded; consists

of protein and polysaccharides.

Integrins

o A transmembrane protein that interconnects the extracellular matrix and

the cytoskeleton.

4.21- Three types of cell junctions are found in animal tissues

Tight junctions

Bind cells together

Found predominantly in epithelial tissues

o Such as the lining of the intestines.

Tight junctions form a barrier that prevents fluids from moving between the

intestinal space and the space between cells.

Animal cells in multicellular tissues are usually joined by tight junctions,

desmosomes (also called anchoring junctions), and gap junctions (also called

communicating junctions). Plant cells are often joined by plasmodesmata. Each

type of junction has specialized functions, such as preventing fluid leakage

between membranes or allowing the free passage of small molecules and ions

between adjacent cells.

Anchoring junctions


19/22

Desmosomes

appear as thickened patches in the cell membrane region between two cells

contain specialized proteins, such as keratin (the same protein found in

fingernails and hair), that increase the rigidity of tissues.

Desmosomes such as those found in epithelium, smooth muscle, and manyother animal tissues are buttonlike junctions that bind cells together and also

function as anchors for fibers in the cytoskeleton.

Gap junctions

Communicating junctions

Two cells are separated by a small gap, which is bridged by specialized channels

that allow the passage of water and small molecules.

Help coordinate the activities of adjacent cells

o a hormone that stimulates one cell will often activate adjacent cells as well

by the passage of intracellular signals through gap junctions.

Plant cells, unlike animal cells, are surrounded by thick walls that form rigid tissues.

They do not need the junctions found in animal tissues.

o But some higher plant cells are interconnected by plasmodesmata

tubelike structures that penetrate through cell walls and form fluid

connections between adjacent cells.

o Like gap junctions in animal cells, plamodesmata allow the free exchange

of small molecules and help coordinate the activities of neighboring cells.

4.22- Cell walls enclose and support plant cells

Vocabulary-


20/22

Cell wall

o A protective layer external to the plasma membrane in plant cells,

bacteria, fungi, and some protists; protects the cell and helps maintain its

shape.

Plasmodesmatao An open channel in a plant cell wall through which strands of cytoplasm

connect from adjacent cells.


21/22

07/12/2009 22:50:00


22/22

07/12/2009 22:50:00

biology notes chapter four complete

Documents