Characteristics of All Cells

CELLS

Characteristics of all cells:

· Smallest living unit

· Most are microscopic

· A surrounding membrane

· Protoplasm/cytoplasm – cell contents in thick fluid

· Organelles – structures for cell function

· Control center with DNA

Discovery of Cells:

Robert Hooke (mid-1600s) - Observed sliver of cork, saw “row of empty boxes”, and coined

the term “cell”

Principles of Cell Theory:

All living things are made of cells

Smallest living unit of structure and function of all organisms is the cell

All cells arise from preexisting cells

Cell Types:

1. Prokaryotic Cells:

· First cell type on earth

· Examples: Bacteria and Archaea

· No membrane bound nucleus

· Nucleoid = region of DNA concentration

· Organelles NOT bound by membranes

2. Eukaryotic Cells:

· Nucleus bound by membrane

· Include fungi, protists, plant, and animal cells

· Possess many organelles

· Representative Animal Cell

· Representative Plant Cell

Organelles: (Cellular machinery. Similar to the “organs” that make our body work.)

1. Cell Membrane

· Outermost layer of animal cells

· Controls what enters/exits a cell

· Movement Across the Cell Membrane

· A few molecules move freely through:

o Water, Carbon dioxide, Ammonia, Oxygen

2. Cell Wall

· Found only in plants, fungi, & many protists

· Surrounds cell membrane

· Protects cell

· Gives shape

3. Cytoplasm

· Viscous fluid around organelles that help stabilize all the cell parts

4. Cytoskeleton

· Filaments & fibers in the cell

Functions:

· mechanical support

· anchor organelles

· help move substances

Cilia & Flagella

Provide ability to move

Cilia

Short hairs

Used to move substances outside human cells

Flagella

Whip-like extensions

5. Nucleus

· Control center of cell

Contains

· Chromosomes (DNA)

· Nucleolus

6. Vacuoles

· Membrane bound storage sacs

· More common and larger in plants than animals

· Contents

o Water

o Food

o wastes

7. Mitochondria

· Break down fuel molecules through “Cellular Respiration”

· Release Energy (ATP)

· Basically the power centers of the cell.

8. Chloroplasts

· Solar energy capturing organelle

· Where photosynthesis takes place to create food for the cell.

Cilia & Flagella

Provide ability to move

Cilia

Short hairs

Used to move substances outside human cells

Flagella

Whip-like extensions

BACTERIA

Characteristics:

· Bacteria are small and unicellular

· They have no internal organelles
(no chloroplasts, nucleus,
ER, mitochondria)

Bacterial forms: (classified by shape):

· cocci(round)

· bacilli(rod shaped)

· spirilli(spiral)

Bacterial pathogens:

Animal pathogens:

· Typhoid, tuberculosis

· Bubonic plague or “Black Death”,
transmitted by fleas (caused
25 million deaths in Medieval
Europe)

· Syphilis, gonorrea (venereal diseases)

· E. coli, Salmonella (food poisoning)
76 million illnesses worldwide

Ways of controlling bacterial growth:

· Disinfectants

· Antibiotics

· Low temperatures

· High temperatures,

· Low oxygen

Benefits of Bacteria:

· Nitrogen-fixation – convert atmospheric N into useful Nitrogen (N gas à plants à animals)

· Decomposition in the biosphere – get rid of dead organisms, nature’s recyclers

· Intestinal Bacteria – supply vitamins (K)

· Commercial use: yogurt, sour cream, fermentation

· Genetically-engineered bacteria produce insulin and other important chemicals.

· Can also help clean up oil spills: oil ‘eating’ bacteria!

PROTISTS

Characteristics:

· 200,000 species come in different shapes, sizes, and colors

· All are eukaryotes – have a nucleus and membrane-bound organelles

Types of:

1. Protozoans

· Animal-like Protists

· Unicellular – made up of one cell

· Heterotrophs – they eat other organisms or dead organic matter

· Classified by how they move

Types of Protozoans

A. Amoebas: the Blobs

· No cell wall

· Move using pseudopods – plasma extensions

· Engulf bits of food by flowing around and over them

B. Flagellates/Euglena: the Motorboats

· Use a whip-like tails called a flagella to move

C. Ciliates/Paramecium: the Hairy Ones

· Move beating tiny hairs called cilia

2. Algae

· Plantlike Protists

· Characteristics: Algae

· Multicellular – made of more than one cell

· Photosynthetic – make their own food

· No roots, stems, or leaves

· Each has chlorophyll and other photosynthetic pigments

3. Fungus-like Protists

Characteristics in Common

· All form delicate, netlike structures on the surface of their food source

· Obtain energy by decomposing organic material

Ex: Mold, Mildew, slimes

GENETICS

What is genetics? “Genetics is the study of heredity, the process in which a parent passes certain genes onto their children.”

Genetic Concepts:

· Heredity describes how some traits are passed from parents to their children.

· The traits are expressed by genes, which are small sections of DNA that are coded for specific traits.

· Genes are found on chromosomes.

· Humans have two sets of 23 chromosomes—one set from each parent.

Gregor Mendel:

Austrian Monk.

Considered the “Father of Genetics”

Experimented with “pea plants”.

Used pea plants because:

– They were available

– They reproduced quickly

– They showed obvious differences in the traits

Understood that there was something that carried traits from one generation to the next

Mendelian Inheritance:

· The inherited traits are determined by genes that are passed from parents to children.

· A child inherits two sets of genes—one from each parent.

· A trait may not be observable, but its gene can be passed to the next generation.

Mendelian Inheritance:

Each person has 2 copies of every gene—one copy from mom and a second copy from dad. These copies may come in different variations, known as alleles, that express different traits.

Example, 2 alleles in the gene for freckles are inherited from mom and dad:

allele from mom = has freckles (F)

allele from dad = no freckles (f)

child has the inherited gene pair of alleles, Ff (F allele from mom and f allele from dad).

Mendelian Genetics Vocabulary:

– Dominant traits- traits that are expressed and are represented by a capital letter in the genotype(AA,Aa)

– Recessive traits- traits that are covered up and are represented by both lower case letters in the genotype (aa).

– Alleles- the different forms of a characteristic.

– Homozygous- two of the same alleles.

– Heterozygous- two different alleles.

– Genotype :

How the genes code for a specific trait.

If the trait is dominant it has atleast one or more capital letters

Example – Tall (Tt, TT)

If the trait is recessive has two lowercase letters

Example – short (tt)

Genotypes always have two letters – one for dad and one for mom

Types of genotype:

· Purebred (homozygous) dominant – the genes only have the dominant trait in its code.

o Example – Dominant Tall -- TT

· Purebred (homozygous) recessive – the genes only have the recessive trait in its code.

o Example – Recessive short – tt

· Hybrid (heterozygous) – the genes are mixed code for that trait.

o Example – hybrid Tall -- Tt

– Phenotype

The outward appearance of the trait.

How an organism looks

How an organism acts

How an organism feels

Tricks to remembering the difference between Genotype and Phenotype

Genotype – deals with GENE CODE.

Phenotype – deals with looks you can take a PHOTO with.

Punnett Squares:

– The Punnett square is the standard way of working out what the possible offspring of two parents will be. It is a helpful tool to show allelic combinations and predict offspring ratios.

Example: A cross between 2 parents for height. Both Parents are heterozygous (Tt)

Tall(Dominant) = T, Short(Recessive) = t

Result ratios:

Dominant = ¾ = 75% chance

Recessive = ¼ = 25% chance

Levels of Organization in the Human Body

Levels of Structural Organization

6 Levels of Organization :

1. CHEMICAL LEVEL

Basic level

Atoms the smallest unit of matter

Essential atoms for life include carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), calcium (Ca), and sulfur (S)

Molecules two or more atoms joined together

Deoxyribonucleic acid (DNA)

Glucose

Levels of structural organization

2. CELLULAR LEVEL

Molecules combine to form cells

Cells are the basic structural and functional units of an organism

Examples: Muscle cells, nerve cells, epithelial cells, etc.

3. TISSUE LEVEL

Tissues are groups of cells and materials surrounding them

Four basic types of tissues:

A. Epithelial Tissue

· Covers the surfaces of the body inside (as lining and/or covering of internal organs) and outside (as layer of skin)

· Connective Tissue

· Connects all parts of the body and provides support.

· Ex: Tendons, ligaments, cartilage

B. Muscle Tissue

· Contracts and shortens, making body parts move.

· Types of muscle = cardiac, smooth, skeletal

C. Nerve Tissue

· Carries impulses back and forth to the brain from the body.

4. ORGAN LEVEL

· Structures that are composed of two or more different types of tissues

· Specific functions and recognizable shapes

· Examples: Heart, lungs, kidneys

5. SYSTEM LEVEL

A system consists of related organs with a common function

Organ-system level

Example = Digestive system breaks down and absorbs food

It includes organs such as the mouth, small and large intestines, liver, gallbladder, and pancreas

Note: Eleven systems of the human body

6. ORGANISM LEVEL

An organism or any living individual

All systems of the body functioning together

***Characteristics of Living Human Organism

Basic Life Processes that distinguish living from non-living things:

· Metabolism

· Responsiveness

· Movement

· Growth

· Differentiation

· Reproduction

***Metabolism:

A condition of equilibrium (balance) in the body’s internal environment

Skeletal System

How many bones does the human skeleton contain?

206

Functions of the skeletal system

· Gives shape & support

· Protects internal organs

· Moves muscles

· Forms blood cells

· Stores calcium and phosphorous

Skeleton is divided into 2 parts:

1. Axial Skeleton

Skull (protects the brain).

Ribs ( protect lungs, and heart).

Spinal column (houses and protects the spinal cord).

2. Appendicular Skeleton

Legs

Pelvis (Protects digestive and reproductive organs)

Arms

Shoulders

Types of Joints

1. Immovable

Skull

Pelvis

2. Movable

Pivot

Ball & socket

Hinge

Gliding

Movable Joints:

1. Ball & Socket: Shoulders and Hips

Allows arms and hips to move in any direction

Can move in a full 360 degrees

2. Pivot Joints: First two neck vertebrae & joint beneath elbow

Moves in a semicircle motion by twisting against each other

3. Hinge: Elbows & Knees

Move like hinges on a door

Limited movement

Can only swing back and forth

4. Gliding Joints: Spine, Wrists, Ankles

Slide against each other in a gliding motion

Gives your wrists and ankles lots of freedom

Layers of the BONE: (outside to inside)

1. Periosteum: soft, thin, covers and protects the bone

2. Compact Bone: Hard, outer surface. Can heal itself when broken

3. Spongy Bone: Porous, contains blood vessels, nerves

4. Marrow: manufactures red blood cells

MUSCULAR SYSTEM

Functions of Muscles:

· Movement – both voluntary & involuntary

· Maintaining posture

· Supporting soft tissues within body cavities

· Guarding entrances & exits of the body

· Maintaining body temperature

Flexors vs Extendors:

1. Flexors

Flexors bend at the joint, decreasing the interior angle of the joint. EX: Bicep

2. Extendors

Opposites of flexors, extensors unbend at the joint, increasing the interior angle.

EX: Tricep

How Muscles Connect to Bones

** Muscles Pull on Tendons to Move Bones at Connections called Joints or Articulations

Tendons: structures that connect bone to muscle and are made up of tendon tissue

Ligaments: connect bone-to-bone or reinforce joints

Cartilage:

Cartilage is connective tissue. Main Function is to reduce friction.

****Muscles DO NOT PUSH. They can only CONTRACT and PULL. ****

Nerves cause the contractions

Digestive System

Functions:

· Ingest food

· Break down food

· Move food through digestive tract

· Absorb nutrients and water

· Eliminates waste materials

Organs that food passes through:

1. Mouth

· Breaks down food into small pieces

· Begins starch digestion (amylase)

· Saliva produces amylase and lubricates food

· Moves food into esophagus

· Epiglottis covers trachea so your food doesn’t go into your windpipe

2. Esophagus

· Pushes food to Stomach

· Peristalsis – The process by which food is moved through the esophagus by the contractions of smooth muscle that squeezes the food down

3. Stomach

· Muscles churn food – mechanical digestion.

· Glands produce gastric juice = pepsin + HCl

· Pepsin breaks down proteins (only at pH 2)

· Food leaves after 2-4 hrs

· Pushes food into small intestine

4. Small Intestine

· Digestion is finished here

· Peristalsis finishes mechanical digestion

· Pancreatic juice produces enzymes to finish chemical digestion of fats, proteins (proteins that catalyze or increase the rates of chemical reactions) and carbohydrates.

5. Large Intestine

· Main function is to absorb water

· Bacteria continues to break down waste/feces

Vocab:

1. Enzyme = Proteins that catalyze (or increase the rates of) chemical reactions

2. Proteins = They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs.

3. Carbohydrates = Molecules that consist of carbon, hydrogen and oxygen atoms. A major food source and a key form of energy for most organisms.

4. Amino Acids = Molecules that are the building blocks of proteins. (Make up 75% of the human body and are essential to nearly every bodily function. Every chemical reaction that takes place in your body depends on amino acids and the proteins that they build.)

Liver:

· Produces bile which is then stored in the gallbladder.

· Helps process food in the small intestine for use by body.

Bile = The greenish-yellow fluid (consisting of waste products, cholesterol, and bile salts) that is secreted by the liver cells to perform two primary

Functions:

· to carry away waste

· to break down fats during digestion

Excretory/Urinary System

Primary Urinary Organs

1. Kidneys

· Two reddish organs just above the waist behind the stomach

· Filter the blood and removes waste

2. Ureters

· Tubes connecting the kidneys to the urinary bladder

3. Urinary Bladder

· Smooth muscle bag

· Stores waste solution - urine

4. Urethra

· Connects bladder to outside of the body

· Allows urine to pass out of the body

What does Urine contain:

· water

· urea, a waste product that forms when proteins are broken down

· urochrome, a pigmented blood product that gives urine its yellowish color

· salts

· creatinine, a waste product that forms with the normal breakdown of muscle

· byproducts of bile from the liver

· ammonia

***Nephrons***

· Filtering unit of the kidney

· Blood enters full of waste and leaves filtered

Some Causes of Kidney Failure

· Diabetes

· High Blood Pressure

· Physical Trauma/Impact

What if your Kidneys Fail?

· Dialysis

· Kidney Transplant

The Circulatory System

The Closed Circulatory System:

Humans have a closed circulatory system, typical of all vertebrates, in which blood is confined to vessels and is distinct from the interstitial fluid. The heart pumps blood into large vessels that branch into smaller ones leading into the organs. Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells.

Three Major Parts of the System – Heart, Blood Vessels, & Blood

1. The Heart-

· cardiac muscle tissue

· highly interconnected cells

· Four chambers:

– Right atrium

– Right ventricle

– Left atrium

– Left ventricle

2. Blood Vessels -A network of tubes that carry blood throughout the body.

Types of: (largest to smallest)

– Arteriesà carry oxygenated blood away from the heart

Elastic Fibers