BIOLOGY 1021

UNIT 1: MULTICELLULAR

STRUCTURE

CHAPTER 15 P. 307-311

AND

CHAPTER 16 P. 328-331

Be sure to know flow chart – an

understanding from atoms to multicellular

organisms.

Importance of carbon, hydrogen, proteins, carbohydrates,

phospholipids, various cellular organelles and their

functions

TWO TYPES OF CELLS (Prokaryotic and Eukaryotic)

Cell

functions:

metabolism

and transport

etc.

REVIEW

REVIEW OF UNICELLULAR ORGANISMS

• Unicellular – 1 cell is the entire organism, microscopic but a highly efficient metabolic machine.

• All life processes must take place within or by that one cell…..

• Reproduction

• Movement

• Diffusion

• Osmosis

• Active transport

• Respiration

• DNA replication

• Protein synthesis enzyme reactions

• Homeostasis…etc..

Unicellular organisms include Bacteria (prokaryotic) and some Protists (Eukaryotic)

• Main disadvantage of being unicellular is the fact if the cell is destroyed then

the organism is also destroyed!

• Protection and Reproduction is VERY important!

1. Produce high number of offspring for very large populations.

2. Have capsule (or pellicles), cell wall and membranes for protection.

3. Sexual reproduction to increase genetic variety (need more energy

so this type of reproduction is less frequent because they prefer to

reserve energy for other metabolic functions needed to survive.

4. Reproduce asexually until it is absolutely necessary to revert to

sexual reproduction.

https://study.com/academy/lesson/kingdom-protista-

definition-characteristics-examples.html

PROTISTS: TYPES OF UNICELLULAR ORGANISMS P. 308

1. Protozoans: protists that display

characteristics similar to animals.

Live in aquatic environments and

some parasitic. They are motile

(use flagella, pseudopods),

eukaryotic and heterotrophic. Ex.

Protists (Giardia – causes Beaver

Fever) (Plasmodium – causes

Malaria)

2. Slime molds – protists that appear like fungus but are not related. Unicellular in structure (have many

nuclei), able to form colonies that make them quite large in size and fungus-like, they feed on dead

plant material.

2 types – slime molds and plasmodial slime molds

TYPES OF UNICELLULAR ORGANISMS P. 309

TYPES OF UNICELLULAR ORGANISMS P. 310

3. Unicellular algae – similar to plants because they photosynthesize – phytoplankton –

they support marine food chains and webs.

Volvox – colonial green algaePHYTOPLANKTON

Dinoflagellates bloom cause RED TIDES

TYPES OF UNICELLULAR ORGANISMS P. 310-311

4. Seaweed – actually multicellular – but each cell is identical and performs its own life

processes. (later in notes) – classified in 3 different groups (Green, red and brown

algae)

UNIT 1: MULTICELLULAR STRUCTURE

• Multicellular Organisms

• To be multicellular means the organism is composed to more than one cell.

• As a result – cells are much larger and can be seen with the naked eye (still

microscopic but millions and billions of cells together eventfully produces a

structure that can be seen.)

• Multicellular organisms can be simply multicellular or multicellular with a

division of labour for life processes!

Simply Multicellular

• Some protists and fungi

• They are composed of many cells and are

thus visible in terms of size but each cell making

up the organism is behaving on its own

independent of each other.

• Like unicellular organisms, each cell is preforming all

characteristic of life, if one of the billions of cells making

up the organism is destroyed, it will occur unnoticed

and the organism continues to function unchanging.

• The numbers or quantity of cells also offers protection,

whereas in a unicellular organism structure is required

for protection.

• Disadvantage – requires excessive energy

2 types of multicellular organisms – Simple –

no division of labour

1. Multicellular protists

2. Multicellular fungi

Seaweed – multicellular – but no division of labour. Every cell

making up the seaweed will perform all the same functions

regardless of their location on the seaweed body.

1. MULTICELLULAR SEAWEED

SEAWEED

• Seaweed the grow on rocky shores are subject to

coastal action – harsh environment – but need to

live here because they need access to sunlight to

photosynthesize.

• Every cell photosynthesizes, are well protected,

perform all their own life processes therefore no

need to an elaborate transport system. Because

they are simply multicellular, they no not have any

form of skeletal or support system which explains

why, out of water, they have no shape. They simply

rely on water for support.

• Seaweed look like plants and are structurally like plants

BUT………………

• They have a holdfast that looks like a root actually holds it to

the rock

• They have a stipe which looks like a stem

• They have a blade which looks like a leaf

• In seaweeds there are no tissues, organs or organ systems, all cells

are identical. Cells of the seaweeds holdfast, stipe and blade are all

similar in appearance and perform all the same functions – every

cell photosynthesize.

• Roots, stems and leaves of a plant are organs composed of very

different tissues with different functions.

• The leaves of a plant are designed for photosynthesis

• The root of the plant are underground and is designed for

anchorage and uptake of water and nutrients – different

function – different cells so no chloroplasts

• Kingdom Fungi – is made up of multicellular eukaryotic cells that also does not form tissues, organs or

systems.

• Cells are not like other eukaryotic cells – but appear as long threads – so long that one nuclei cannot

control the entire length – therefore several nuclei are present. These cells are called hyphae.

• Fungi are composed of numerous hyphae that can make the fungi large in size (ex. Mushroom)

• All cells or hyphae are absorptive heterotrophs with the ability to produce substances to dissolve

nutrients that can then be absorbed into the cell. All cells or hyphae contain cell walls comprised of

chitin for support – as they do not have a support or skeletal system.

1I. MULTICELLULAR FUNGI P. 328

• All the hyphae in a mushroom are the same

above ground in the cap or in the stalk that is

below ground. (no division of labour)

• Fungi are very important decomposers. They help recycle nutrients.

• Beneficial.

• Eat mushrooms and truffles

• Culture fungi to produce antibiotics and other drugs - Penicillin

• Culture to make cheese and ferment alcohol

• Make bread rise

They can also be parasitic

Vaginal yeast infections, athletes foot, jock itch

P. 330

2. Multicellular with division of labour

• An organism of many cells that conserves energy, by division

of labour for life processes.

• The division of labour conserves energy via brining each

organelle together as a team and gives each a certain function.

• This creates a much more efficient organism.

• Cells Tissues Organs Organ systems

• To be multicellular with division of labour, the organism must

have tissues, organs and organ systems rather than just simply

composed of many cells

• The organisms as a result will be much larger, more complex and

highly efficient!

• Although losing one cell may not be as detrimental in term of the

organism as a whole, all components of the system must work

together since they are concerned only with their own function.

• Therefore, losing a tissue, organ and especially an organ system

WILL be detrimental to the organism as a whole, since then the

entire function will also be lost.

Tissues – a group of cells of similar shape and size that perform one specific

function. Ex. Muscle tissue – many cells working together to perform the

function of movement or contraction OR Nervous tissue – many cells working

together to perform their function of receiving and transmitting impulses.

Organs – a group of tissues working together for a specific function. Ex.

Stomach is an organ composed of several tissue types such as epithelial tissue,

muscle tissue ans connective tissue, all working for breakdown of materials.

Organ system – A group of organs working together for a specific function. Ex.

Digestive system is composed of various organs such as the stomach, intestine,

colon whose function is digestion. The cardiovascular system is composed of

vital organs such as the heart, veins, arteries that work together for transport.

LAB # 1