AP Bio Unit 2

Cells

The smallest unit of life

What are the two types of cell?

Prokaryotes and eukaryotes

Eukaryotic cells traits

Multicellular, contain membrane bound organelles, larger than prokaryotes, and store DNA in the nucleus

Chromatin

a complex of DNA, RNA, and proteins (primarily histones) located in the eukaryotic cell nucleus

Before going through eukaryotic cell division what does the DNA organize itself into?

Chromosomes

Eukaryotic kingdoms

Animalia, Plantae, Fungi, and Protista

What are the traits of prokaryotic cells?

Unicellular, DON'T contain membrane bound organelles, smaller than eukaryotes, and store DNA in the nucleoid

What do all cells have?

A cytoplasm, a plasma membrane made of phospholipids, and ribosomes

Nucleolid

Where the DNA information is stored in prokaryotes (not membrane enclosed)

Fimbriae

Attachment structures on the surface of some prokaryotes

Ribosomes

Synthesize proteins

Plasma membrane in prokaryotic cells

The membrane that encloses the cytoplasm

cell wall

Rigid structure outside the cell membrane

Glycocalyx

Outer coating of prokaryotes that consists of a layer of slime

Flagella

Moves some prokaryotes

Nucleus

Where DNA information is held in eukaryotic cells

nuclear envelope

the outer membrane of the nucleus made of phospholipids

What does the nuclear envelope do?

It sperates the DNA from the cytoplasm

nuclear pores

Little openings in the nuclear envelope that assist with protein synthesis

Nuclear Lamina

Array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus

Nucleolus

Found inside the nucleus and produces ribosomes

Peroxisomes

An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide

Purpose of peroxisomes

Using oxygen to break down fatty acids into smaller molecules and peroxisomes in the liver detoxify alcohol and other harmful compounds

Glyoxysomes

Specialized peroxisomes found in the fat-storing tissues of plant seeds

Endomembrane system

A group of membrane bound organelles that carry out various tasks within the cells

What's the flow of the endomembrane system?

Rough ER, then to the Golgi, and finally to the plasma membrane where materials can be exported from the cell

What are the functions of the endomembrane system?

modifying, packaging, and transporting different macromolecules throughout the cell

What organelles make up the endomembrane system?

Golgi Apparatus, Lysosomes, Vacuoles, Transport Vesicles, Nuclear envelope, Plasma membrane

Transport vesicles

Tiny sacs made of a phospholipid bilayer that can be used to transport materials between the endomembrane system

Rough ER

A network of membranes that surround the nucleus and a continuous membrane with the nuclear envelope that's covered in ribosomes

What's the role of the rough ER?

Helps carry out protein synthesis and packages proteins made by the embedded ribosomes into transport vesicles

Secretory proteins

Proteins made in the rough ER that will be secreted outside the cell

Products of the rough ER

glycoproteins, secretory proteins, phospholipids

Smooth ER

A network of membranes that surround the nucleus and a continuous membrane with the nuclear envelope

What is the role of the smooth ER?

Synthesizes lipids and breaks down certain toxins in the cell

What are the products synthesized by the smooth ER?

Lipids like oils, steroids, and new membrane phospholipids

Golgi Apparatus

Series of flattened membrane sacs

What are the different faces of the golgi apparatus?

Cis and trans face

Cis face of the golgi apparatus

close to the ER and receives the products from the ER

Trans face of the golgi apparatus

opposite side of the golgi and secretes the products

What is a product the Golgi makes?

polysaccharides

What is the Golgi Appartus's role?

Responsible for receiving, sorting, and shipping cellular materials

What does the golgi do with recently synthesized products?

it packages them into transport vesicles

Plasma membrane

The outer layer of the cell made of phospholipids

What makes up the plasma membrane?

phospholipids that formed a double-layered structure known as a phospholipid bilayer

Besides the phospholipids what other molecules does the membrane contain?

Protein and cholesteral

What is the plasma membrane's role?

Controls what enters and exits the cell and maintains boundaries between internal and external environments

Lysosomes

Membranous sacs that contain hydrolytic enzymes

Where are hydrolytic enzymes synthesized?

by ribosomes from the rough endoplasmic reticulum

How do hydrolytic enzymes break down macromolecules?

Through hydrolysis

What do lysosomes digest?

intracellular materials and waste

Vacuoles

Membrane bound sacs that play different roles depending on the type of cell

Centeral vacuoles

that store water, nutrients, pigments, and even certain toxins that protect plants against herbivores

What's the role of centeral vacuoles?

helps plants maintain turgor pressure which is a force that pushes against the cell wall of plant cells to help them maintain their shape

Vacuoles in animal cells

Have more, smaller vacuoles that store nutrients and other cellular materials

Contractile vacuoles

pump excess water out of the cell, maintaining water balance

What are the main functions of the cytoskeleton?

Maintain cell shape, anchor organelles, allows Intracellular transport, anables cell movement, important in cell division

What is the structure of the microfilaments?

Made of actin, thinnest fibers, flexible

What are the functions of microfilaments?

Muscle contractions, cell movement, cytoplasmic streaming, cleavage furrow during cytokinesis

What is the structure of intermediate filaments?

Made of various proteins like keratin, provide structural support, more stable and permanent

What are the functions of intermediate filaments?

Maintains cell shape, anchor nucleus, form the nuclear lamina

What is the structure of microtubules?

Made of tubulin, hollow tubes, thickest fibers

What are the functions of microtubules?

Tracks for organelle movement, for mitotic spindle, make up cilia and flagella, helps separate chromosomes during mitosis

Motor proteins

Use ATP to move along cytoskeleton fibers

Cilia

tiny, hair-like organelles that extend from the surface of many eukaryotic cells, functioning as either sensory antennas or moving mechanisms

What are traits of the cilia?

Short hairs found in large amounts and moves back and forth (beating)

What is the function of the cilia?

Moves fluid across a surface

flagella

Long, whip-like appendages primarily used by cells for locomotion

What are traits of the flagella?

Long appendages in small amounts and moves in a whip-like motion

What is the function of the flagella?

To move the entire cell?

What powers the movement of cilia and flagella?

Dynein

What are the cilia and flagella extensions of?

The cytoskeleton

Endosymbiotic theory

Proposes that the early ancestor to modern eukaryotic cells engulfed prokaryotes, but they did not digest them, they formed a symbiotic relationship

What is evidence from the mitchondria and chloroplasts that support the endosymbiotic theory?

Both contain their own DNA (which is circular like prokaryotes), their own set of ribosomes, and can reproduce on their own within the cell

Mitochondria

Found in almost all eukaryotic cells and is responsible for conducting cellular respiration to synthesize ATP

What is the structure of the mitochondria?

The outer membrane is smooth whereas the inner membrane is highly folded and the space between the two membranes is called the intermembrane space

Plastid

A specialized, double-membrane bound organelles found in plant and algae cells, crucial for manufacturing and storing food

Chloroplasts

Found in all photosynthetic organisms and are responsible for conducting photosynthesis

Stroma

The fluid portion inside the chloroplast

Thylakoids

A membrane system inside the chloroplasts

Granum

Stacks of thylakoids

What is the pigment inside of the thylakoids that caputres light from the sun?

Cholrophyll

Cell wall

structure that provides extra support and rigidity for the plant cell

What is the cell wall made of?

Cellulose (for plants) Chitin (For fungi)

Cellulose

a polysaccharide and a fiber that makes up the cell wall

What is the function of the cell wall?

Plants maintain structure and protect them from bursting due to too much water

Volume

The amount of space enclosed within an object

Surface area

The total area that the surface of the object has

What is the relationship between surface area and volume?

Surface area increases proportionally less than volume

The rate of diffusion of materials into and out of a cell is related to...

Surface Area

What does a larger surface area mean?

The more materials can be exchanged into/out of the cell

What would happen if metabolic rate of a cell were to exceed the cell's ability to exchange important materials?

The cell would die

Why do many organelle have highly folded membranes?

To increase their surface area needed for metabolic reactions

Metabolic reaction

Any chemical process that occurs within a living cell to maintain life, converting nutrients into energy, building blocks, or waste products

What happens as organisms increase in size/volume?

Their SA:V ratio decreases meaning they struggle exchanging materials with the environment

Metabolic rate

the speed at which your body breaks down food and converts it into energy

What's the relationship between size and metabolic rate?

The smaller the organism, the higher the metabolic rate per unit of body mass

Why do cells need to be in membrane-bound compartments?

Because hundreds of different cellular processes occur simultenously so they must be organized so they don't disrupt each other

What is a reason for compartmentalization?

So membrane bound organelles with different functions can be near eachother as they are related to similar processes (Ex: Golgi and the Rough ER)

Do prokaryotes still have compartmentalization even though they don't have membrane bound organelles?

Yes, they still compartmentalize certain metabolic processes into different regions of the cell