Biology - Chapter 2

Prokaryotic Cells (simple)

Prokaryotic Cells (simple)

• Produce single-celled arganisms (archaea, bacteria)

• No nucleus

• Very small

• Found in: Kingdoms Archaea and Eubacteria (both types of bacteria)

Eukaryotic Cells (complex)

• Produce single-celled (protists) or multicellular organisms (fungi, animals, plants)

• Contains a nucleus and membrane-bound organelles

• Tens to thousands of times larger than prokaryotic cells

• Found in: Kingdoms Protists, Fungy, Animalia, and Plantae

Plant Cell Diagram

Know...

• Vacuole

• Cell Wall

• Mitochondrion

• Endoplasmic Reticulum (E.R)

• Cell Membrane

• Cytoplasm

• Ribosome

• Chloroplast

• Chromosomes

• Nucleus

• Nucleolus

Animal Cell Diagram

Know...

• Nucleolus

• Chromosomes

• Nucleus

• Ribosome

• Mitochondrion

• Cell Membrane

• Cytoplasm

• Endoplasmic Reticulum (E.R)

• Golgi Body

• Lysosome

• Centrioles

• Vacuole

Cytoplasm

• Throughout entire cell

• Jelly-like liquid, depending on the chemical reactions taking place

• Holds substances that cells store until needed

• In plant and animal cell

Cell Membrane

• Outer layer

• Flexible, double layer, surrounds cell

• Supports cell and allows some substances to enter while keeping others out

• In plant and animal cell

Nucleus

• Near the centre of cell

• Roughly spherical

• Carries instructions for all cell processes

• In plant and animal cell

Mitochondria

• Throught cytoplasm

• Large, oval with a convoluted double membrane (lots of surface area)

• Converts food to energy and contains enzymes that help cellular respiration take place

• In plant and animal cell

Endoplasmic Reticulum

• Throughout cytoplasm

• Three dimensional network of branching tubes and air pockets

• Transport materials through the cell

• In plant and animal cell

Golgi Bodies

• Throughout cytoplasm

• Stacked discs

• Stores and secretes materials for cell use

• In plant and animal cell

Vacuoles

• Throughout cytoplasm

• Single layer of membrane enclosing fluid in a sac

• Contain some substances, remove unwanted substances, maintain internal fluid pressure within the cell

• Many small ones in animal cells, one large one in plant cell

Cell Wall

• Just outside the cell membrane

• Rigid, but porous structure made of cellulose

• Provides support for the cell and protection from physical injury

• In plant cell

Chloroplast

• Through cell membrane

• Looks like small, green, dots

• Absorb light energy

• In plant cell

Ribosome

• Throughout cyctoplasm

• Small, spherical granules

• Full of water and keeps cells plum

• In plant cell

Labelling the microscope

Know...

• Eyepiece/Ocular lens

• Eyepiece tube on body tube

• Nosepiece

• Arm

• Objective lenses

• Stage

• Stage clips

• Diaphragm

• Coarse focus

• Fine focus

• Illumination

• Base

Magnification

Low - 40x Medium - 100x High - 400x Very High - 1000x

Micrometers

1mm = 1000μm

Actual Size Calculation (μm)

Field of View (μm) ÷ # of times it fits across FOV (Field of View)

Drawing Magnification

Drawing size (μm) ÷ Actual size (μm)

Cell division

Required for:

• Reproduction

• Growth

• Tissue Repair

Cell Division for Reproduction - Asexual

• Only one parent

• Single parent divides to form 2 duaghter cells, genetically identical

• Common in single-celled organisms

• Used for growth and tissue repair in multicellular organisms

Cell Division for Reproduction - Sexual

• Two parents

• Each parent produces gametes (half cells - sperm and egg) through meiosis

• Gamete contains half of the DNA found in a cell

• Gamete from each parent fuse to form the 1st cell of new life. Then it divides and grows through mitosis

• New offspring is genetically unique

Cell Division for Growth

• All organisms grow

• When multicellular organisms grow, the number of cells increase

• Cells obtain/transport materials through diffusion and osmosis

Concentration

The amount of a substance (solute) present in a given volume of solution

Osmosis

A fluid, usually water, travels across the cell membrane from an area of low solute concentration (more water) to an area of high solution concentration (less water)

Diffusion

Chemicals (ex.nutrients) travel across the cell membrane from an area of high concentration to an area of low concentration

Cell Division for Repair

• All organisms need to be able to repair themsevles when damaged or replace dying cells in order to survive

• Different types of cells get replaced at different times: stomach lining cells replace after 2 days, red blood cells after 120 days, brain cells only after 30-50 years

Cell Cycle

• Interphase

• Mitosis

• Cytokinesis

Interphase

• Longest stage of th cell cycle (90% of a cells life)

• 3 Stages of interphase: G1, S, G2

Interphase - G1

Cell grows, produces more organelles, carries out normal activities

Interpahse - S

DNA replicates to produce 2 identical copies

Interphase - G2

Cell prepares to divide

Mitosis

• Involves the division of the contents of the nucleus

• 4 stages (PMAT)

• In animal Cells, Mitosis is "helped along" by spindle fibers (spindle fibers are specialized structures produced by centrioles that attatch to the chromosones and help pull them apart)M

Mitosis - Prophase

Chromosomes condense and centrioles move to opposite poles, forming spindle fibres. Each chromosome has 2 identical sister chromatids that are held together by a centromere

Mitosis - Metaphase

Sister chromatids line up in a single file along the middle of the cell

Chromosomes are most visible in the phase for plant mitosis

Mitosis - Anaphase

Sister Chromatids separate to opposite poles

Mitosis - Telophase

Chromosomes unravel, nuclear membrane reforms, and cell appears to have 2 nuclei

Each new cell will secrete cellulose to form the cell wall for plant mitosis

Cytokinesis

Cell divides and 2 genetically identical daughter cells form. Daughter cells in interphase

Membrane pinches off in animal cell Plate forms across centre of cell which forms the cell wall in plant cell

Cancer

Uncontrolable and rapid division of cells caused by the mutation in the portion of the DNA controlling the cell cycle

2 Types of Cancer

Malignant tumors Benign Tumors

Malignant tumor

Affects surrounding cells Metastatic cells can leave the tumor and start a secondary tumor elsewhere

Benign

Does not affect surrounding cells, unless by physically crowding them

Causes of Cancer

Some mutations are caused by carcinogens (environmental factors that cause cancer) Some carcinogens are: Tobacco smoke Radiation (X-Rays, UV Rays) Viruses (HPV, Hepatitis B) Some chemicals in plastics Organic solvents Genetic links

Dectecting Cancer

Endoscopy X-Ray Ultrasound CT scan MRI

Preventing Cancer

avoiding tobacco smoke eating a healthy diet eating vitamin supplements and 'super foods'

Treating Cancer

Surgery (physically removing the cancerous tissue) Chemotherapy (using drugs to slow or stop the cancer cells from dividing and killing them), Radiation (damaging the DNA of many daughter cells so they cannot divide further)

What is a specialized cell

a cell that can perform one job really well due to physical and chemical differences

Speicialized animal cells

Red Blood Cells Skin Cells Bone Cells Muscle Cells White Blood Cells Sperm Cells Fat Cells Nerve Cells Photophore Cells

Red Blood Cells

Contain hemoglobin that carries oxygen in blood Smooth so they can pass through blood vessels

Skin Cells

Fit together tightly to vover outside of body Protects cells inside and reduces water loss

Bone Cells

Collect calcium Allow growth and repair of bones

Muscle Cells

Arranged in bundles called muscle fibers Can contract and causes bones to move

White Blood Cells

Can move like amoeba to engulf bacteria and fight infectionSp

Sperm Cells

Able to move independently Carry DNA from male parent to join an egg from female parent

Fat Cells

Have large vacuole that stores fat molecules How cells store chemical energy

Nerve CElls

Long, thin, many branches Conduct electrical impulses to coordinate body activity

Photophore cells

Emit light and used by animals that are active at night or live deep in the ocean