Marine BiologyLife in the Sea

Part 2

September 9, 2014Module 2

Class Challenge

Share a line from your Favorite Movie

Quiz # 3

List Levels of Organization in Living Systems

(Smallest to Largest)

Levels of Organization inLiving Systems

Atom – The smallest unit of an elementMolecule – A chemical unit that results from atoms bonding togetherCellular Organelle – A well defined structure within a cellCell - The basic organizational unit of living materialTissue – A grouping of similar cells with a specific functionOrgan – A body part made of tissues performing as a unitOrganism – An individual capable of reproductionPopulation – A group of interbreeding organisms coexisting togetherCommunity – Integrated populations living in a limited areaEcosystem – A community and the physical features of its environment

Diversity of Life

http://youtu.be/wxjSx9wluAQ

Wet Lab at South Lido

A Tour of the Cell

Bozeman Science: John Anderson

http://youtu.be/1Z9pqST72is

• There are two major kinds of prokaryotes:

• Bacteria 

• Archaea (single-celled organisms) 

• Biologists now estimate that each human being carries nearly 20 times more bacterial, or prokaryotic, cells in his or her body than human, or eukaryotic, cells.

• If that statistic overwhelms you, rest assured that most of these bacteria are trying to help, and not hurt, you. Numerically, at minimum, there are 20 times more prokaryotic cells on Earth than there are eukaryotic cells.

• This is only a minimum estimate because there are trillions of trillions of bacterial cells that are not associated with eukaryotic organisms.

• all Archaea are also prokaryotic. As is the case for bacteria, it is unknown how many Archaean cells are on Earth, but the number is sure to be astronomical. In all, eukaryotic cells make up only a very small fraction of the total number of cells on Earth. 

There are four main structures shared by all prokaryotic cells,

bacterial or Archaean:

• The plasma membrane 

• Cytoplasm 

• Ribosomes 

• Genetic material (DNA and RNA) 

Some prokaryotic cells also have other structures like:

• the cell wall, • pili (singular pillus), and • flagella (singular flagellum).

• Each of these structures and cellular components plays a critical role in the growth, survival, and reproduction of prokaryotic cells.

There are big differences between eukaryotic and prokaryotic cells, but they do have some things in common:

1. Both have DNA as their genetic material.2. Both are encased in membranes. The

membranes of Prokaryotic cells and of some eukaryotic cells are surrounded by a strong cell wall.

3. Both have a similar basic metabolism (the word metabolism refers to the formation and break down of chemicals in the body).

• The major difference is that eukaryotes have a nucleus and prokaryotes do not.

• Prokaryotes – no nucleus – think before the egg.

Eukaryotic Cell

 You are a eukaryote and have eukaryotic cells.

A cell is defined as eukaryotic if it has a membrane-bound nucleus. Any organism composed of eukaryotic cells is also considered a eukaryotic organism. Case in point: You. 

Biologists do not know of any single organism on Earth that is composed of both eukaryotic and prokaryotic cells.

However, many different types of prokaryotic cells, usually bacteria, can live inside larger eukaryotic organisms. Creepy, but true.

All of the organisms we can see with the naked eye are composed of one or more eukaryotic cells, with most having many more than one.

This means that most of the organisms we are familiar with are eukaryotic.

However, most of the organisms on Earth, by number, are actually prokaryotic.

Here are some examples of eukaryotes:

• Animals 

• Plants 

• Fungi (mushrooms, etc.) 

• Protists (algae, plankton, etc.)

• Most plants, animals, and fungi are composed of many cells and are, for that reason, aptly classified as multicellular,

• while most protists consist of a single cell and are classified as unicellular. 

All eukaryotic cells have • A nucleus

 • Genetic material

 • A plasma membrane

 • Ribosomes

 • Cytoplasm, including the cytoskeleton

 

Most eukaryotic cells also have other membrane-bound internal structures called organelles.

• Organelles include

• Mitochondria 

• Golgi bodies 

• Lysosomes 

• Endoplasmic reticulum 

• Vesicles

There are a few major differences between animal, plant, fungal, and

protistan cells,  All plant cells have

• A cell wall made of cellulose 

• A large central vacuole 

• Chloroplasts

Some animal and protistan cells have

• Flagella 

• Cilia 

All animal cells have

• Centrioles

All fungal cells have

•  cell wall made of chitin.

The nucleus in the cell is analogous to the brain in the body. It is a control

center for a cell.

The nucleus stores all the information the

cell needs to grow, reproduce, and function.

This information is contained in long but thin molecules of deoxyribonucleic acid, or DNA.

One of the functions of the nucleus is to protect the cell’s DNA from damage, but that is not all that it does. The nucleus is basically a large membranous sac. 

The nucleus also contains a small round body called a nucleolus that holds nucleic acids and proteins.

The nuclear membrane has pores through which the contents of the nucleus communicate with the rest of the cell.

The nuclear membrane tightly controls what gets into the nucleus and what gets out. This regulation of communication by the nuclear membrane has a great effect on what a cell looks like and what it does.

Chromosomes are also located in the nucleus and are basically organized structures of DNA and proteins.

In eukaryotes, the chromosomal DNA is packaged and organized into a condensed structure called chromatin.

Chromosomes are single pieces of DNA along with genes, proteins, and nucleotides, and chromatin is a condensed package of chromosomes that basically allows all the necessary DNA to fit inside the nucleus.

In eukaryotic organisms, the DNA inside the nucleus is also closely associated with large protein complexes called histones.

Along with the nuclear membrane, histones help control which messages get sent from the DNA to the rest of the cell.

The information stored in DNA gets transferred to the rest of the cells.

• The cytoplasm in eukaryotic cells is a gel-like, yet fluid,

substance in which all of the other cellular components are suspended, including all of the organelles.

• The underlying structure and function of the cytoplasm, and of the cell itself, is largely determined by the cytoskeleton, a protein framework along which particles in the cell, including proteins, ribosomes, and organelles, move around.

• You can think of the cytoskeleton as a type of 3D "highway system" with roads running in every direction, including up and down. The cytoplasm is the thick fluid in which the "highway system" is suspended and through which cellular materials are transported.

• Helpful tip: Whenever you see "cyto" as part of a word, think "inside the cell."

Eukaryotic Cell

• Eukaryotic cells contain a wide variety of organelles (tiny "organs" or structures inside the cell) that perform various functions.

• Some of the most important organelles are mitochondria, chloroplasts, lysosomes and ribosomes.

The basic structure of an eukaryotic cell:

• The membrane (the outside or coating)

• The nucleus (the place where the DNA is stored and from where instructions are sent to the rest of the cell for the production of proteins. The nucleus has its own membrane)

• The cytoplasm or cytosol, which contains everything between the membrane and the nucleus (including organelles)

• Eukaryotic cells are, on average, ten times as large as prokaryotic cells.

• Their DNA is more complex and is formed into chromosomes.

• And their organelles enable them to do more complex jobs.

• Most plants are made up of eukaryotic cells.

• But eukaryotic plant cells are different from eukaryotic animal cells.

• And the biggest difference is the cell membrane.

• In animals (like us) the membrane is the actual outside of the cell.

• But plants have something extra -- a cell wall that goes all the way around the outside of the membrane, shown with the brown shading (see Figure 2.3, page 39)

• The main difference between plant cells and

animals cells is this -- plant cells have a cell wall and animal cells don't.

• This cell wall is made of cellulose.

• Cellulose is important in human nutrition since it provides fiber (roughage), which keeps your digestive system going. That's why it's important to eat a diet rich in plant material like fruits, whole grains and vegetables.

Levels of Organization in Living Systems: Table 2.1

AtomMoleculeCellular OrganelleCellTissueOrganOrganismPopulationCommunityEcosystem

Life in the Blue Really HD BBC Beautiful Ocean Life

http://youtu.be/LL59es7iy8Q

Challenges that Marine organisms have in their ecosystem

Of course their habitat is the Ocean. Life is abundant and found in all areas of the sea. But oceans are vast and varied.

How are the oceans around the earth different….???

Ocean animals have special features that enable them to survive in the unique conditions of their environment.

Barnacles attach to solid rock and withstand the surge of rough waves.

Some fish can live among the poisonous tentacles of jellyfish;

Large whales feed on microscopic plankton in wide, open-ocean areas;

Flounder lay flat on the ocean floor, perfectly matching the color and texture of sand.

Some special features of marine organisms have to do with keeping their bodily conditions stable.

In the ocean, marine organisms have to survive in a medium that could disrupt their internal metabolism, so they must maintain a fairly constant internal condition to survive. This is called homeostatis.

Homeostatis

Defined as the tendency of living organisms to control or regulate changes in their internal environment.

Poikilotherm• An organism whose body temperature

changes with its surrounding environment.

• It is the opposite of a homeotherm, an organism which maintains thermal homeostasis.

HomeothermAn animal that maintains a controlled internal body temperature using its own heating and cooling mechanisms.warm-blooded is a colloquial term to

describe animal species that have a relatively higher blood temperature, and maintain

thermal homeostasis primarily through internal metabolic processes. These are characteristics of mammals and birds.

Ectotherm

An organism whose body temperature is controlled by its surrounding environment.

EndothermAn animal whose internal body temperature

is a result of internal sources of heat.  (birds, mammals, some fishes and insects, and even some plants) 

Homeotherm and Endotherm

• One internal source of heat comes from their muscles. Heat is generated from muscle activity and is released into their internal tissues as a means of warming them.

• Another source of heat is controlled by their rate of respiration. If an organism can increase its respiration, it will make more heat from the burning of fats and other molecules.

• This is an advantage in that these

organisms can maintain a warm body temperature in cold water and remain very active.

• At the same time, higher respiration rates use up lots of energy. Many of these animals are insulated with thick layers of blubber, hair, or feathers so that only small increases in respiration are needed to warm their internal temperatures.

See Figure 2.4 (Page 46)

• Angelfish

• Shark

• Dolphin

Experiment 2.3: The Cell

Objective: To be able to identify prokaryotic cells and Eukaryotic cells.

Supplies:MicroscopePrepared Slides

Experiment 2.3: The Cell The Prokaryotic CellThe vast majority of cells on Earth are

actually prokaryotic,

There are two major kinds of prokaryotes:

• Bacteria 

• Archaea (single-celled organisms) 

There are four main structures shared by all prokaryotic cells, bacterial or

Archaean:• The plasma membrane

 • Cytoplasm

 • Ribosomes

 • Genetic material (DNA and RNA) 

Some prokaryotic cells also have other structures: the cell wall, pili (singular pillus), flagella (singular flagellum).

Each of these structures and cellular components plays a critical role in the growth, survival, and reproduction of prokaryotic cells.

Experiment 2.3: The Cell

The Eukaryotic Cell

Homework1. Complete OYO questions for Module 2 to 2.12;2. Complete Study Guide for Module 2;3. Finish Experiment 2.4: The Cell4. Module 2 Test;5. Read Module 3: Pages 55-656. Quiz on the parts of the cell7. Notebook check through Module 2

8. Further Study: http://www.shmoop.com/biology-cells/all-eukaryotic-cells.html