Unit 1

Basic Biological Principals

Studying Life

• Biology: The Study of life• All organisms (a living things) have eight

characteristics that make them living

Studying Life

1. Living things are based on a universal genetic code. – All organisms store their information in the form

of DNA– DNA is copied and passed from parents to

offspring– http://www.pbs.org/wgbh/evolution/library/04/4/l_044_02.html

Studying Life

2. Organisms Grow and Develop– Each organism has a specific pattern of growth

and development– Example: A single egg is fertilized, divides, cells

become specialized to do different functions– http://www.youtube.com/watch?v=xmsTccmRMh4

Studying Life

3. Organisms Respond to their Environment– Stimulus: a signal to which an organism responds– Organisms can respond to a number of stimuli.

Example: Invasion of territory– http://www.youtube.com/watch?v=XgRHKLyBkMU

Studying Life

4. Organisms are made of cells– Composed of one or more cells– Smallest unit of an organism– Cells can grow, respond to surroundings,

reproduce– http://www.youtube.com/watch?v=ZK6YP1Smbxk

Studying Life

5. Taken as a group, organisms evolve– Groups of organism evolve, or change over time.– Evolution links all life forms to a common origin

more then 3.5 billion years ago– Evidence: from fossils, proteins, DNA sequence,

similar structures– http://www.pbs.org/wgbh/evolution/library/11/2/e_s_1.html

Studying Life

6. Organisms obtain and use material and energy– Must take in energy and materials to grow,

develop and reproduce– Metabolism: combination of chemical reactions

through which an organism builds up or breaks down materials

– http://www.dnatube.com/video/156/introduction-to-metabolism

Studying Life

7. Organism maintain a stable internal environment– Homeostasis: Keeping a stable internal

environment even when external conditions change

– http://www.phys.unsw.edu.au/biosnippets/

Studying Life

8. Organisms reproduce– Sexual reproduction: Cells from two parents unite

to form the first of a new organism, genetically different from parents

– Asexual Reproduction: Single organism produces offspring identical to itself

Check Point

• What eight characteristics do all living things share?

Life is Cellular

• Brief timeline of the development of life on Earth:– 4.6 billion years ago the Earth was formed– 3.5 billion years ago the first life arose: prokaryotic

bacteria– 1.5 billion years ago eukaryotic cells arose– ½ billion years ago the Cambrain explosion: multi-

celled eukaryotes arose– 3 million years ago our earliest ancestors, the

hominids, appeared

Life is Cellular

• Types of Cells:– Prokaryote: Cells that do not separate their

genetic material within a nucleus– Eukaryote: Cells with a nucleus that separates the

genetic material from the rest of the cell– http://dsc.discovery.com/videos/assignment-discovery-shorts-

eukaryote-prokaryotes.html

Life is Cellular

• Prokaryotes and Eukaryotes Similarities– Both have DNA as their genetic material– Both have a plasma membrane– Both contain RNA– Both are made from the same basic chemicals: carbohydrates,

proteins, nucleic acids, lipids– Both have ribosomes– Both regulate the flow of materials into and out of them– Both have similar basic metabolism (photosynthesis/reproduction)– Both require a supply of energy– Both are highly regulated by sensing systems to sense their

environment

Life is Cellular

• Prokaryotes and Eukaryotes Differences– Eukaryotes contain a nucleus with DNA, prokaryotes do not

have a nucleus, their DNA floats freely in the cytoplasm– Eukaryotes contain many different organelles, prokaryotes

do not, some only contain ribosomes– Eukaryotes are about ten times larger then prokaryotes– Both may have cell walls but prokaryotes are made of

different material then eukaryotes– Flagella (structures that help cells move) are arranged

differently in both types of cells. Far more complex in Eukaryotic cells them prokaryotic cells

Life is Cellular

• Evolution of cells:– Present day cells evolved from a common

prokaryotic ancestor– Endosymbosis: Certain organelles were acquired

into eukaryotes by engulfing prokaryotes. This is seen with the mitochondria and chloroplast. They both have separate DNA, are similar in size to bacteria and reproduce by dividing in two

– Thought to have evolved in aerobic and photosynthetic bacteria

Check Point

• How are eukaryotic and prokaryotic cells different?

Cell Structure

• Cell Organization– The cell is divided into two major parts• The cytoplasm• The nucleus

Cell Structure

• The Cytoplasm– Portion of the cell outside the nucleus– Prokaryotes and eukaryotes both have a nucleus– The cytoplasm holds the organelles– Organelles- structures in the cell that act like

specialized organs that make the cell run correctly and efficiently

– http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=related

Cell Structure• The Nucleus– Contains nearly all the cell’s DNA and, with it,

coded instructions for making proteins and other important molecules

– Surrounded by a double membrane called the nuclear envelope with nuclear pores, which allow materials in and out, like RNA and proteins

Cell Structure

• The Nucleus– Chromosomes, which carry the cell’s genetic

information, are housed in the nucleus. – Chromosomes are spread out and threadlike

through the nucleus. In this state they are called chromatin- a complex of DNA bound to proteins

– Nucleolus- small dense region in the nucleus, where assembly of ribosomes begins

– http://www.youtube.com/watch?v=tRo73dzVfuo

Check Point

• What is the function of the cell nucleus?

Cell Structure

• Vacuoles– Large, sac-like, membrane enclosed– Store materials like water, salts, proteins and

carbohydrates– Central vacuole- In plant cells, filled with liquid to

increase rigidity– Contractile vacuole- In unicellular organisms and

some animals, pumps excess water out of the cell.– http://www.youtube.com/watch?v=zW9B3jC-1Xc– http://www.youtube.com/watch?v=hUkZwSHZjhY

Cell Structure

• Vesicles– Smaller then vacuoles, membrane enclosed

structures– Store and move materials between cell organelles

and the cell surface

Cell Structure

• The Cytoskeleton– Network of protein filaments that give cells their

shape, internal organization and movement– May carry materials from one part of the cell to

another or move the entire cell

Cell Structure

• The Cytoskeleton– Microfilaments: Made of a protein called actin, tough flexible

frame work that supports the cell. Also help the cell move (amoebas crawl along the surface with cytoplasm movement)

– Microtubules: hollow structure made up of tubulin. Maintain cell shape, cell division (form mitotic spindle used to separate chromosomes)

– Centrioles are microtubules found in animal cells only that help with cell division

– Microtubules also build cilia and flagella which control movement

– http://www.youtube.com/watch?v=5rqbmLiSkpk&feature=related

Check Point

• What are the functions of vacuoles, lysosomes, and the cytoskeleton?

Cell Structure

• Ribosomes– Ribosomes are small particles of RNA and protein– Proteins are assembled here by following

instructions from DNA– Protein factory– http://www.youtube.com/watch?v=Jml8CFBWcDs

Cell Structure

• Endoplasmic Reticulum– ER is where lipid components of the cell membrane,

proteins and other components are assembled– Rough ER: Ribosomes are found on its surface. Newly

made proteins leave the ribosomes and are inserted into the rough ER were they are modified. These proteins will be released, secreted or transported to other areas of the cell

– Smooth ER: No ribosomes attached, contain enzymes that synthesis membrane lipids and detoxify drugs (liver)

– http://www.youtube.com/watch?v=PASnAaulK-Y

Cell Structure

• Golgi Apparatus– Proteins from the rough ER come here to get

modified, sorted, and packaged for storage in the cell or release outside the cell

– Puts the finishing touches on the proteins– Looks like flattened sacs of membranes– http://www.youtube.com/watch?v=bD4z27ASN1M

Check Point

• What organelles help make and transport proteins?

Cell Structure

• Chloroplast– Solar power for plants– Capture energy from sunlight and convert in into

food that contains chemical energy in a process called photosynthesis

– Membrane bound, contain chlorophyll– Have their own genetic information, DNA,

endosymbiotic with prokaryotes– http://www.youtube.com/watch?v=LTglday5zak

Cell Structure

• Mitochondria– Power plants of cell– Convert chemical energy stored in food into compounds that

are more convenient for the cell to use– Two membranes with the inner membrane folded to

increase surface area– Mitochondria only come from the egg during fertilization, so

all the mitochondria in the worlds population come from the mother

– Have their own genetic information, DNA, endosymbiotic with prokaryotes

– http://www.youtube.com/watch?v=RrS2uROUjK4

Check Point

• What are the functions of chloroplast and mitochondria?

Cell Structure

• Cell Wall– Main function is for support, shape and protect– Not found in animals cells– Porous, allow water, oxygen, carbon dioxide and

other substances to pass through easily– Cell walls are found in all plants. Made of

cellulose

Cell Structure

• Cell Membranes– Cell membrane regulates what enters and leaves

the cell and protects and supports the cell– Made of a lipid bilayer which gives the membrane

its chemical properties. Fatty acid head of a lipid is called hydrophilic (water loving), the tail is hydrophobic (water hating)

– http://www.youtube.com/watch?v=-aSfoB8Cmic

Cell Structure

• Cell Membrane– Fluid Mosaic Model: Proteins are embedded in the

lipid bilayer and can “float” so it looks like the membrane is moving or fluid

– Carbohydrates are attached to the proteins and act as identification cards, the proteins act as channels or pumps to get materials through or help change the shape of the cell

– Selectively permeable: Some material can pass through the membrane some can not

– http://www.youtube.com/watch?v=ULR79TiUj80

Check Point

• What is the function of the cell membrane?

Cell Specialization/Differentiation

• Cell differentiation starts from a single fertilized egg, with one set of DNA and cellular components. Each cell in the organism has the same genetic blueprint.

• There are three basic categories of cells that make up the mammalian body: Germ cells ( give rise to sperm and ova), somatic cells (body cells that for different tissues and organs) and stem cells (able to divide for an infinite period and give rise to specialized cells)

• During differentiation certain genes are turned on, or become activated, while other genes are switched off, or inactivated

• http://www.teachersdomain.org/resource/tdc02.sci.life.stru.different/

From One Cell To Many

• Embryo: developmental stage from which an adult organism is gradually produced

• Differentiation: Process by which cells become specialized. During the development of an organism, cells differentiate into many types

• Differentiation determines a cells identity, how a cell will spend its life

• In mammals adult cells do reach a point at which their differentiation is complete, they can no longer become other types of cells

Check Point

• How do cells become specialized for different functions?

Stems Cells and Development

• Totipotent: a cell that can literally do everything, to develop into any type of cell in the body. Only the fertilized egg and the cells after the first few divisions are totipotent

Stem Cells and Development

• Human Development– Blastocyst: After four days of development a

hollow ball of cells with a cluster of cells inside known as the inner cell mass.

– The cells begin to specialize, outside cells form tissues that attach to the mother, inside cells are called pluripotent, can develop into most, but not all, of the body’s cell types

Stem Cells and Development

• Stem Cells: the unspecialized cells from which differentiated cells develop. Sit at the stem of development from which different cell types form– Embryonic Stem Cells: they are the pluripotent cells.

Can form into other cells, large amount of research– Adult Stem Cells: Referred to as multipotent, meaning

they can develop into many types of differentiated cells. Have limited potential. Example bone marrow cells

– http://www.youtube.com/watch?v=mUcE1Y_bOQE

Check Point

• What are stem cells?

Stem Cell Research

• Potential benefits– Stem cells offer the potential benefit of using

undifferentiated cells to repair or replace damaged cells and tissues

• Ethical Issues– Human embryonic stem cell research is

controversial because the arguments for it and against it both involve ethical issues of life and death. Harvesting embryonic stem cells means killing the embryo

Check Point

• What are some possible benefits and issues associated with stem cell research?

Cell Specialization/Differentiation

• Levels of organization– Somatic cells differentiate into different levels of

organization• Tissues• Organs• Organ Systems

Cell Specialization/Differentiation

• Tissues– Group of similar cells that perform a particular

function• Epithelial Tissue: line in interior and exterior of the

body, skin and stomach lining• Connective tissue: provides support and connects the

body parts, fat cells, bone cells, blood cells. Produce collagen, give tissues strength and resilience• Nervous tissue: transmit nerve impulses• Muscle tissue: provide movement, some we control,

like arm and leg, some we do not, like your pupil

Cell Specialization/Differentiation

• Organs– A group of different types of tissues that work

together to perform a single function or many related functions

• Organ Systems– A group of organs that perform closely related

functions

Check Point

• How does cell differentiation work?

Cell Specialization/Differentiation

• Organ Systems– Nervous System: Brain, Spinal cord, nerves. Recognizes

and coordinates the body’s response to changes in its internal and external conditions

– Integumentary System: Skin, hair, nail, sweat and oil glands. Guard against infection/injury/sunburn, regulate body temperature

– Immune/Lymphatic System: White blood cells, thymus, spleen, lymph nodes. Protects the body from disease, collects fluid lost from blood vessels and returns it to the circulatory system

Cell Specialization/Differentiation

• Organ Systems– Muscular System: Skeletal, smooth, cardiac. Produces

voluntary movement, circulate blood, aid in digestion– Circulatory System: Heart blood vessels, blood.

Transports oxygen, nutrients, and hormones to cells, fights infection, removes cell waste, regulates body temperature

– Skeletal System: Bones, cartilage, tendons. Supports the body. Protects internal organs, allows movement. Stores minerals, produces blood cells

Cell Specialization/Differentiation

• Organ Systems– Respiratory System: nose, pharynx, larynx,

trachea, bronchi, lungs. Brings in oxygen, removes carbon dioxide

– Digestive System: mouth, pharynx, esophagus, stomach, small and large intestine, rectum. Breaks down food, absorbs nutrients, removes wastes

– Excretory System: Skin, lungs, liver, kidneys, ureters, urinary, bladder, urethra. Eliminates waste products from the body

Cell Specialization/Differentiation

• Organ Systems– Endocrine System: Hypothalamus, pituitary,

thyroid, parathyroid, adrenals, pancreas, ovaries, testes. Control growth, development, and metabolism, maintains homeostasis

– Reproductive System: Testes, epididymis, vas deferens, urethra, penis, ovaries, Fallopian tubes, uterus, vagina. Produces gametes, in females nourishes and protects the embryo

– http://www.youtube.com/watch?v=po8D290YF9o

Check Point

• How is the human body organized?