Cell Anatomy notes (Chapter 6)
I. CHARACTERISTICS OF LIVING THINGS:
-All are composed of the same 4 basic elements:
1) carbon (C)
2) hydrogen (H)
3) oxygen (O)
4) nitrogen (N)
In addition, iron (Fe); calcium (Ca); phosphorus (P); and sulfur (S) are important elements to life.
spontaneous generation - theory life from nonliving matter. Cells come from other cells.
6 CHARACTERISTICS of Life:
1) movement
2) metabolism - all chemical activities in an organism essential to life.
*Building up and breaking down process.
4 activities of metabolism:
1. ingestion - eating.
*take it in (consumers) or make their own food (producers)
2. digestion - process by which food is broken down into simpler substances.
3. respiration - process by which living things take in oxygen and use it to produce energy.
food + oxygen = energy
4. excretion - process of getting rid of waste materials.
EX – H2O; CO2; ammonia; urea
3) growth and development
specialization - cell structure to perform specific function.
-Organisms increase in size: number of cells increase and become more complex
-metamorphosis - a developmental process in which an animal changes drastically in body form between the
juvenile and the adult.
EX – caterpillar to butterfly; tadpole to frog
4) life span - maximum length of time a particular organism can be expected to live.
-Varies in different organisms.
Shortest: mayfly-5 minutes
animal-gastrotrich-3 days
Longest: bristlecone pine-over 5000 years
animal-tortoise-177 years
Human: 122 years documented
Methusalah—969 years
5) stimulus (stimuli) - (cause) signal to which an organism reacts.
response - (effect) some action or movement of the organism brought on by a stimulus.
-Can be voluntary or involuntary
6) reproduction - process by which living things give rise to the same type of living thing.
2 types:
1) asexual reproduction -formation from a single cell; reproduction without gametes.
2)
0
(one cell)
/\
0 0 (becomes two cells)
2)sexual reproduction -formation two different cells; reproduction involving gametes
X Y (a female and male gamete-sex cell)
\/
0 (becomes one new cell)
fertilization - joining of egg and sperm
II. NEEDS OF LIVING THINGS:
6 NEEDS of Living Things:
1) energy
-All living things need energy.
-The primary source of energy for most living things is from the sun. (photosynthesis or chemosynthesis)
2) food and
3)water
-65% of our body is water
70%--cell
90%--cytoplasm
-Substances dissolve in water and can be transported easily.
-Chemical reactions cannot take place without water.
EX - metabolism would shut down; wastes would build up.
4) air is made of:
78% N
21 % O
(organisms need *oxygen)
.97% trace gases:
H, He, Ra, Xn, H20
.03% CO2
5) living space
6) proper temperature
homeostasis - conditions inside same, conditions environment change.
III. HISTORY AND BACKGROUND OF THE CELL
cell - unit of living thing; building block of life.
anatomy - study of structure. (part; what it is)
physiology - study of functions. (job; what it does)
cell - (Latin) “little room”
EX - jail cell; cell phone
cytology - study of cells.
-Sir Robert Hooke was the first to describe the cell. (1665) He discovered them looking under a
microscope. He observed dead cork cells. Since cork comes from living trees, it can be determined that
the small unit Hooke saw in the cork, was the basic unit of life—or a cell. He didn’t actually understand this but he
did name the small unit the cell because he raised bees and the small section of a honeycomb is called a cell.
Unified Cell Theory
cell theory - basic unit of life, composed of one or more cells, cells from other cells.
3 parts:
1) All living things are made up of cells
Schleiden (botanist) and Schwann (zoologist) (1838); worked independently
2) Cells are the basic units of structure and function in all organisms
3) All cells are produced by other living cells
Virchow (Russian)
-Cells are different sizes and shapes
EX - smallest—bacteria (17,000 in a cm)
longest—nerve (1 meter)
largest—bird’s egg (ostrich)
-Humans (adults/average) have 100 trillion cells
-Newborns have 26 billion cells
-One-celled (unicellular) organisms include:
algae, ameba, bacteria, diatoms, dinoflagellates, euglena, hydra, paramecium, yeast, etc.
-*All cells have these 4 parts:
1) cell membrane - outside boundary
2) cytoplasm - living contents of the cell and holds organelles in place
3) genetic material (DNA/chromosome)
4) ribosomes - site of protein synthesis
IV. PROKARYOTIC AND EUKARYOTIC CELLS (by kingdoms)
2 types of cells:
1. Prokaryotes (Diagram #1)
prokaryotic cell (prokaryotes) - simplest cell, no true nucleus
(Kingdoms: Archaea and Bacteria)
-no true nucleus; one chromosome that is circular
2. Eukaryotes (Diagram #2)
eukaryotic cell (eukaryotes) - complex cell with nucleus.
(Kingdoms: Protista, Fungi, Plantae, and Animalia)
-Have membrane-bound organelles; a true nucleus; varied number of chromosomes
organelle - parts cell.
-Not all eukaryotic cells will have every organelle (more variety)
1) cell membrane - thin, envelope.
-Holds the cell together and regulates passage of materials in and out of the cell (the “gate keeper”)
In - food and O2 (oxygen); Out - wastes and CO2 (carbon dioxide)
-Flexible; aids in homeostasis
2) cell wall - outermost boundary.
-Only found in archae, bacteria, fungi, and plants.
3) cytoplasm – gelatin-like substance.
-The jelly-like (neither solid nor liquid) matter that is outside the nucleus and within the cell membrane. It holds
the organelles in place. It’s made of 90% H2O and is constantly changing.
4) nucleus (plural-nuclei)- spherical organelle.
-The small, dark, round part inside the cell. It consists of the nuclear membrane, nucleolus, and
chromatin.
-It’s the control center for the cell’s activities (the “brain”) –controls living, growing and reproduction.
5) nuclear membrane - thin membrane.
-It regulates what passes between the nucleus and the cytoplasm.
-Nuclear pores are the places materials enter and leave the nucleus.
“Pores are the doors.”
6) nucleolus (plural-nucleoli) - structure in nucleus of RNA and protein.
-Called the “little nucleus.”
-There may be more than one. It’s the storage site for RNA and the site for formation of amino acids that are used
in protein building at the ribosomes.
-Not found in plants.
7) chromatin - makes up chromosomes.
-It looks like small grains of sand; it is made of DNA and protein.
8) chromosome - rod-like object in nucleus.
-Made of nucleic acid (DNA/RNA.) DNA stays in the nucleus; RNA travels to the ribosomes.
-“Blueprints” of a new cell. Chromosomes pass on characteristics (genes - a specific part of a
chromosome or sequence of DNA that determines a particular feature or characteristic in an
organism) to new cells or offspring and control the making of proteins necessary to life.
*Humans have 46 chromosomes. 23 from the egg (mom) and 23 from the sperm (dad).
9) centrosome - organelle outside nucleus; involved with mitosis.
10) centriole - two parts in centrosome.
-The two parts separate during prophase of cell division, forming a spindle between them.
11) endoplasmic reticulum (ER) - tubular passageways; involved in the manufacture and transport of proteins. A
network of winding channels that connect the nuclear membrane to the cell membrane. There can be 1- 15.
Smooth ER will become rough ER (which have ribosomes.)
12) ribosome - grain-like body of RNA attached to endoplasmic(ER).
-Ribosomes synthesize (make) proteins; a cell may possess 1/2 million ribosomes.
13) mitochondrion (plural-mitochondria) - oval-shaped structure.
-A double membrane, mostly oval, numerous body scattered throughout the cell.
-Called the “powerhouse.”
-This is where respiration takes place.
Food + oxygen = energy
respiration - process by which living things take in oxygen and use it to produce energy.
-Food is broken down for energy. (This is chemical energy.)
-Mitochondria are like batteries—use and store ATP
FYI—Human liver cells have 1000 mitochondria.
Mitochondria have been theorized to have evolved from bacteria.
Evidence:
1) One chromosome
2) Circular DNA
3) Reproduce independently
14) chloroplast - organelle contains green pigment.
-Food-making site in green plants.
chlorophyll - green substance.
“chlorophyll fills chloroplast”
-Chloroplasts are to photosynthesis as mitochondria are to respiration.
-Chloroplasts and mitochondria are the same in the following ways:
1) contain DNA
2) two membranes and
3) reproduce
independently.
15) Golgi apparatus (body) - stack of flat sacs.
-They store and convert or modify proteins
-They are very numerous in cells that produce secretions.
16) lysosome - small, round structure. lyso - “break apart” / soma - “body” EX - Lysol
-Are small enzyme-filled sacs or digestive packets. They release enzymes when large particles enter
the cell and when the cell dies. The enzymes destroy the particles and digest the remains of the cell.
-Called the “suicide packets.”
-Common in animal cells but not in plant cells.
17) vacuole - large, round sac in cytoplasm.
-Storage for water, food, enzymes, wastes and/or other materials.
-In animals, they are numerous and small.
-In plants, they have one, large vacuole.
V. DIFFERENCES BETWEEN PLANT AND ANIMAL CELLS
Plant cells have, animal cells don’t:
1) cell wall - rigid, outer layer that helps keep its shape
2) chloroplast with chlorophyll inside
Animal cells have, plant cells don’t:
1) centrosome (centrioles)
2) lysosomes
3) nucleoli
Animals and plant cells have, but different:
1) vacuole
plants - one, large
animals - numerous, small
Note: In biology, there are exceptions to almost everything.
The end! 