Biology 11 Unit B

Cell Theory

organisms are

• composed of one or more cells,

• cells are building blocks of life,

• cells come from pre-existing cells

Membrane

• Outer edge of cells that contain the cytoplasm.

• Made of lipids with proteins embedded in them.

• They are specialized — not all have the same abilities or functions.

• Control the movement of matter in and out of the cell.

Cytoplasm

• Interior of a cell.

• Mostly water and in it are suspended many ions, molecules and structures required to maintain the cell’s metabolic activities.

Protoplasm

The cell membrane and everything in it

Chromosomes

Made of DNA; all the cells of an organism will have the same chromosomes

Genes

• Functional sections of chromosomes.

• Contains a chemical sequence that codes for a particular protein.

Ribosomes

Where proteins are made.

Proteins

These biomolecules are what our DNA codes for. Have many functions:

• transport channels in the cell membranes

• cell structures

• enzymes

• Some are exported tor use outside the cell

Microtubules

Elongate fibres made up of protein “tubules”; used to construct cilia and flagella.

Cilia

• Tiny projection, hair-like structures that typically cover cells.

• Wave in an undulating manner to either move the cell or to move fluids over the surface

Flagella

• Longer than cilia.

• If present, there are usually 1-3.

• Aid in moving the cell.

Cytoskeleton

• Organelles don’t just float around freely.

• Cells have a skeleton that form a 3-dimensional framework for structures to anchor to.

• This is what allows for cells to be different shapes, and allows cells to move things (like trains on tracks)

Cell walls

• Plants, fungi, and some single-celled organisms have these.

• Animal cells do not have these.

• Provide support and protection,

• But restricts movement making it difficult for these cells to obtain nutrients, secrete products, and expel waste.

• Composed of large carbohydrate polymers.

Prokaryotic Cells

• Lack a true membrane bound nucleus

• Lack other membrane bound structures (organelles)

• Metabolic functions occur in cytoplasm - inefficient & slow

• Cell materials float randomly - less likely for reactions to occur

• Bacteria and archaea

Eukaryotic cells

• Contains membrane-bound organelles

• Creates compartmentalization (subdivision)

• Many diverse reactions occur at the same time - more efficient, diversified, more specialized

• Typically 10-100x the size of prokaryotes (plants/fungi are the largest)

Nucleus

Contains DNA - controls and regulates activities of the cell

Vacuole

Storage - ingestion/digestion —> excretion

Plants have bigger storage systems due to cell wall making export of waste difficult

Vesicles

• transport, store, deliver various substances: lipids, proteins, nutrients, waste management

Endoplasmic Reticulum

Smooth: Synthesis of lipids and detoxification

Rough: Synthesis/modification of proteins

Both transport via vesicles

Golgi Bodies

Transport and modifications of molecules

Packaged into vesicles

Lysosomes

• digestive/recycling system of the cell

• contain enzymes that break down waste, foreign invaders, and old or damaged cell parts into smaller, reusable components.

• produced by the golgi bodies

Mitochondria

Generate chemical energy (ATP) to power biochemical reactions - cellular respiration

Chloroplast

Photosynthesis - sun energy —> glucose (chemical energy)

Compartmentalization

cell divides its space into small, distinct regions to do specific tasks/functions - only in eukaryotes

Microvili

Cell membrane extensions that increase the amount of exposed surface area

Surface Area

greater surface provides more potential nutrients to enter the cytoplasm

Endocytosis

The process by which food particles become ingested. The food gets surrounded by a section of cell membrane to form a “food vacuole.” The contents are later digested.

Photosynthetic Autotrophs

Cells that:

• depend on energy in sunlight to create glucose

• photosynthesis contain chloroplast, utilizing chlorophyll molecules which are sensitive to visible light

• plants

Chemosynthetic Autotrophs

cells that:

• get energy from inorganic chemical compounds — sulfur or methane.

• live in extreme environments( such as deep sea vents)

Heterotrophic organisms

• Animal and fungal cells

• Ingest/absorb nutrients

• In heterotrophs, nutrients must cross cell membrane

• Single-celled heterotrophs ingest food by endocytosis (pacman thing)

• All kingdoms except plantae have heterotrophs

Cellular Respiration

The collection of chemical reactions that allows the cell to process and get the energy from nutrients. These reactions start with glucose and end with the production of ATP

ATP

• “Energy Currency” of the cell

• Sugar(ribose) + adenine + 3 phosphate sugars

• When enzymes break the last bond, a lot of energy is released that can do work

Glycolysis

Cellular process that breaks glucose (6-carbons into two 2-c molecules. CO2 is a waste product. Next, the 2 molecules go to the mitochondria to form ATP.

• If no glucose: lipids and/or proteins can be used

• Extra glucose: in animals, stored as glycogen. in plants, starch(energy), or cellulose(cell wall)

Anaerobic Respiration

• Prokaryotes have no mitochondria, no aerobic respiration

• “Obligate anaerobes”

• Only produce 2 ATP for 1 glucose

Aerobic Respiration

Cellular respiration thst occurs in the mitochondria when oxygen is present

• One glucose = 38 ATP

• Waste is CO2 and H2O

• “Obligate aerobes”

• No oxygen = lactic acid for energy — “the burn”

Yeasts

• Single-celled fungi

• Facultative anaerobes

• Normally function aerobically, but when oxygen is present

• Fermentation pathways are used for energy

• Biproduct is ethyl alcohol

Protein Synthesis

All cells make proteins.

• Proteins function as enzymes,

• chemical markers on cell surfaces,

• or are secreted out of the cell.

• The recipe for protein is found in DNA and the ingredients of proteins are amino acids.

Protein Secretion

Some cells produce hormones to be secreted out of the cell:

• protein hormones — insulin, produced in the rough ER

• estrogen + testostorone — produced in smooth ER

Steps of the secretory pathway:

• product is produced in the ER

• product leaves ER by “blebbing” in membrane-bound sacs called transport vesicles

• Transport vesicles fuse with the Golgi bodies to chemically alter the product to its final form

• Product blebs from the Golgi into secretory vesicles

• Secretory vesicles fude with cell membrane and contents are expelled, “Endocytosis”

Cell reproduction

Cells reproduce through mitosis and meiosis

Asexual reproduction

Unicellular organisms often reproduce by mitosis in the form of binary fission. Like in our body cells, chromosomes replicate, divide equally, so each “new” cell has an exact cooy of the DNA. In environmentally favourable conditions, unicellular organisms can be mass-produced

Sexual reproduction

During sex cell formation(meiosis), the chromosomes undergo “recombination”. The new cells (very!) genetically distinct:

• variations could provide a reproductive or survival advantage when faced with environmental pressures

Unicellular Prokaryotes

• Kingdom Bacteria (E. coli, streptococcus, staphylococcus)

• Kingdom Archaea (methanogens)

• single-celled organisms

• lack membrane-bound organelles

Unicellular Eukaryotes

• Mainly in Kingdom Protista (amoebas, paramecium, algae)

• yeast (unicellular fungi)

• More complexity than prokaryotes because they have membrane-bound organelles

• Single celled organisms

Multicellular Eukaryotes

• Millions of cells

• Organized into tissues which make organs and organ systems.

• Can grow large and become highly complex with sophisticated adaptations and abilities

• Examples: humans, flowers, trees, palm tree, sloth, amanitas