Ch. 7-1: Cell Structure How were cells discovered? What defines cell shape and size? What enables eukaryotes to perform

more specialized functions than prokaryotes do?

Cells are the basic unit of life.

By studying cells, biologists can better understand life’s processes

Cells and their discovery Cells are the smallest units of matter

that can be living Characteristics of living include: take in

energy, highly organized, reproduce, homeostasis, adapt, respond, grow and made of cells

Cells are composed of C,H,N,O,P,S; often arranged into macromolecules Proteins, carbohydrates, lipids and nucleic

acids

Persons involved in discovery

Anton von Leeuwenhoek : microscope

Robert Hooke : term ‘cell’ Robert Brown : nucleus M. Schleiden : all plants have cells T. Schwann : all animals have cells R. Virchow : cells from other cells

Diversity of cells Human body has at least 200 types of cells

(within our trillions of cells) Size

Can be meters long, but only m thick Surface area to volume ratio limits size, inefficient if

either too large or too small Shape

Squamous, cuboidal, spherical Internal Organization

Organelles = ‘little organ’ or ‘organ –like’ “Cell Specialization”

Microscope Types

Compound Light Microscope (CLM) Light through, stain, 2000x

Stereo scope or Dissecting scope 3-D

Electron Microscope Scanning Electron Microscope (SEM) Transmission Electron Microscope

(TEM)

Prokaryotes vs. Eukaryotes Cell membrane Cytoplasm Genetic material And ribosomes Bacteria only Small Many have cell wall that is

either carb (Gram+) or lipid (Gram-)

May have cilia or flagella Only 1 circular chromosome (+ maybe some plasmids) No membrane-bound

organelles

Cell membrane Cytoplasm Genetic material And ribosomes Plants, animals, protista

and fungi Plants have CW= cellulose

and fungi have CW = chitin, some protista have walls

Variety of organelles and structures

Many chromosomes in a NUCLEUS

Lots of membrane bound organelles

Cell Theory Cells are the basic structural and

functional units of all living organisms All parts of all plants are made of cells All parts of all animals are made of

cells All cells come from pre-existing cells

“Working document” with new discoveries added as the technology becomes available. For instance viruses are not cells and we are trying to create cells. Accumulation of information since 1600’s through electron microscopes

Cell Membrane Refers to all membranes

everywhere cells have them in all cells.

Selectively permeable Certain substances are allowed to enter freely,

some are carried across, some are rejected Phospholipid bilayer

Two rows of lipid tails that face each other with phosphate head that are on the surfaces

Fluid mosaic Proteins that are within membrane can migrate Integral proteins Peripheral proteins

LOTS more on this in Chpt. 8

Cytoplasm (aka protoplasm) Everything inside the cell membrane Just the liquid is called cytosol Cyto = cell Mostly water Dissolved proteins, enzymes, amino

acids, carbohydrates, salts, minerals, organic compounds……

Site of all chemical reactions ‘parts’ within the cell are organelles

7-2 Organelles What does the cytoskeleton do? How does DNA direct activity in the

cytoplasm? What organelles participate in protein

production? What is the role of vesicles in the cell? How do cells get energy?

Knowing how cells work helps you understand how your body functions and

what goes wrong when you get sick.

Organelles – USE your chart (Chart will be a handout and on website)

Mitochondrion Ribosome ; free and attached Endoplasmic reticulum ; smooth and rough Golgi apparatus/body Lysosome and peroxisomes Cytoskeleton ; microtubules and microfilaments Cilia and flagella Nucleus – nuclear membrane, chromosomes and

centrioles Cell wall Vacuoles – food, water, pigment Plastids - Chloroplast, chromoplast and leukoplast Water vacuole in plants sometimes called tonoplast

Sample PROTISTA

7-3: From Cell to Organism What makes cells and organisms

different? How are cells organized in a complex,

multicellular organism? What makes an organism truly

multicellular?

Diverse cells have unique cells and cellular organization.

Organization Unicellular – organisms like bacteria and

algae that are complete, but only one cell Colonial organisms – function as a group

with some division of labor, but no specialized tissues. Ex. volvox

Multicellular – organisms composed of many (thousands to billions) of cells that are organized around collections of specialized tissues

Multicellular Organization Similar cells = tissue Tissues doing a similar job = organ

Plants have reproductive, vegetative and ground tissue

Organs then collect into organ systems to make the organism

Integumentary, skeletal, muscular, nervous (CNS, PNS), digestive, circulatory, respiratory, reproductive, excretory and endocrine. Also immune system and lymphatic system.

Critical thinking questions: leave space for answersThese HW questions are due on ___________

1. Mature RBC’s have no nucleus or mitochondria. They are mostly membrane with hemoglobin. What is the advantage? __________

2. Coils of a radiator provide a huge surface area where heat is radiated into a room – which organelle is similar? How is structure related to function? ______________________________________

3. What characteristic of eukaryotic cells gives them greater capacity for specialization than prokaryotic cells? ______________________

4. Livestock in the western US die after eating locoweed (Astragalus toanus). The chemical in the plant is poisonous. How does the plant keep from poisoning itself? _________________________________

5. Explain the relationship between surface area and volume. ______