Biology - Cells

Classic Cell Theory

*Theorized by Scwann, Schleiden, Virchow

1. All living things are made from cells

2. Cells are the basic units of structure and function

3. New cells come from pre-existing cells

Modern Cell Theory

1. Cells contain genetic material to be passed down

2. All cells are similar in chemical composition and function

3. All energy flow occurs in the cell

Viruses

Has RNA but lack the enzyme to process it, so they take the enzymes from its host. Does the same with raw molecular material. Viruses are NOT alive.

Prokaryotic cells

• NO membrane bound organelles

• NO nucleus only nucleoid

• One circular chromosome

• part of the bacteria and archaea domain

• Some bacteria has “plasmids”

• Bacteria cell walls contain “peptidoglycan”

• Divides through binary fission

• Electron transport system is in the folds of the plasma membrane

PARTS OF PROKARYOTIC CELLS: Capsule, cell wall, cytoplasm, cell membrane, nucleoid region, pili, flagella, ribosomes, plasmids

Capsule

Outer protection that keeps the cell moist

Cell wall

Outermost layer that gives the cell its shape

Cytoplasm

Made of enzymes, salts, and cell organelles. The gel-like component of the cell.

Cell membrane

Surrounds the cytoplasm, regulates the transport of materials in and out of the cell

Nucleoid region

Where the genetic material is located in the cytoplasm

Pili

Hair-like outgrowth that helps the cell stick to the surfaces of other cells

Flagella

long tail-like structure that helps with movement

Ribosomes

Involved in protein synthesis

Plasmids

Non-chromosomal DNA structures not involved in reproduction.

Eukaryotic Cells

• HAS a nucleus

• Bigger and more complex

• Part of the eukarya domain

• NO cell wall

MAJOR PART: Endomembrane system

Organelles for structure

• cell membrane

• cell wall

• cystoplasm

Cell membrane

the layer that keeps everything inside

• made of a phospholipid bilayer and proteins

• Semipermeable

Cytoplasm

Jelly-like liquid that keeps insides suspended

• Made of cytosol (a liquid made of inorganic and organic materials) and internal structures

Cell Wall

the PLANT CELL’S protective outer layer

MAJOR PART: Bio synthesis organelles

Organelles in charge of making stuff in the cell

• nucleus

• ribosomes

• Rough endoplasmic system

• Smooth endoplasmic system

• Golgi apparatus

Nucleus

Stores genetic material used for protein synthesis

• Interior is called nucleoplasm

  • Nucleolus: makes ribosomes

  • Chromatin-Chromosomes: has DNA

Nuclear envelope has pores which mRNA exits, it’s also connected to the endoplasmic teiculum

Ribosomes

Site of protein synthesis: RNA from the nucleus to synthesize into proteins

• attached to the endoplasmic reticulum

  • makes secretory proteins (released in response to body needs)

  • ON THE OTHER HAND free proteins are floating around

Rough endoplasmic reticulum

Membrane studded with ribosomes. Makes secretory proteins.

• In charge of communication, signaling, and physiological processes

Smooth Endoplasmic Reticulum

A tubular organelle with no ribosomes. It produces lipids and carbohydrates. Similar to the liver it breaks down toxic substances.

Golgi apparatus

Flattened stacks of membranes that modifies, sorts, and packages substances that’ll be used inside and out of the cell.

Trans face

• concave and faces the cytoplasm (transport)

Cis face

• Convex and faces endoplasmic reticulum (receive)

MAJOR PART: energy processing organelles

Organelles that process energy.

• chloroplast

• mitochondria

Chloroplast

type of plastid (organelle that has different pigments) that has the green pigment molecule: chlorophyll

• used for photosynthesis

Mitochondria

the powerhouse of the cell

• glucose is turned into ATP

MAJOR PART: transport and storage organelles

for transporting and storing materials

• vacuole

• vesicle

Vacuole

Storage bubble that stores nutrients in the cell.

Storage compartment of substances

Vesicle

Compartment of substances. Used to transport materials.

MAJOR PART: organelles that decompose

• lysosome

• peroxide

Lysosome

Digests and breaks down food using enzymes. Has specialized vesicles containing the enzyme hydrolases that break down substances or old cellular parts.

peroxisome

specialized vesicles that has enzyme catalase that breaks down peroxide (H2O2) into hydrogen, oxygen, and water.

MAJOR PART: cytoskeleton/s

• microtubules

• intermediate filament

• microfilament

Microtubules

Enables internal parts to move

• made of centrioles, spindle fibers, and appendages (flagella, cilia)

intermediate filament

Anchors internal parts into place and provides mechanical strength, cell shape, and stability

microfilament

Enables cells to change their shape, for example organisms like amoeba, forming pseudopodia.