3. Plant Cells & Tissues

Cellulose is universally difficult to break down.

-That's why we use it to build with. -We can't break it down (that's what fiber is) -Plants just drop their leaves because they can't break the cellulose down to recycle it. -mainly only fungi and some microbes can break it down. Termites, cows, cockroaches, pandas all have microbes inside of them that break down the cellulose for them.

Turgor Pressure

-The cell insides (protoplast) pushes on all sides of the wall, much like a balloon filled with oxygen. -When the plant doesn't have enough water so it cannot push up against the wall, the plant droops, wilts, and the wall folds inward. -It is often the large vacuole filled with things that creates the turgor pressure.

There are 3 major cell types found in plants

1. Epidermal Cells (Make up epidermis) 2. Parenchyma Cells (Make up cortex) 3. Tracheary Cells (Make up vascular tissue)

Hemicellulose

A

Pectin

A protein that makes a substance firm and jelly-like. It is found in the primary wall (pliable wall), and is produced by the cell when it is time to expand to wall. The substance makes the wall more pliable, and able to stretch.

*Plant Cell Walls* 1. Primary Wall 2. Secondary Wall

Cell wall is a bunch of cellulose fibers and hemicellulose fibers in a pectin substance. 1. The primary wall is pliable/stretchable and grows while the cell does. External Wall. 2. The secondary wall is strong, rigid, and unchanging. It is formed after the cell is finished growing. -mostly formed in areas that need lots of support - like xylem. -formed INISDE OF the primary walls. Internal Wall. -mostly lignin and lots of cellulose. -makes it waterproof - that way water can't leave the plant.

Epidermal Cells

Cells that are tightly packed together and form the outermost layer of the plant. They are coated by a waxy cuticle which they secrete. Their function is to protect the interior cells (from desiccation and from attack by bacteria and fungi)

Cellulose Synthase

Cellulose is created by a protein complex on the cell membrane called "cellulose synthase".

The cell wall is constructed out of cellulose

Cellulose is polymer of glucose molecules. These strands are coiled around each other like strands in a cable.

Central/Chief Vacuole Tonoplast

Central/Chief Vacuole - a very large storage vacuole in the plant cell. (possibly taking up a quarter of the size of the cell). Tonoplast - The large membrane around the vacuole.

Callose

Chains or glucose that strengthen a cell wall. They are often produced in response to fungi attacking the plant.

Cisternae

Cisternae - disks that make up the golgi apparatus

Flagella and cilia

Flagella and cilia are both appendages that a cell uses for locomotion (to move). Flagella is generally a single long whip-like tail, while cilia are many small finger like appendages. (could be thought of as oars) Both types are created out of microtubules. (9 sets of 3 tubes plus 2 inside) They're mainly found in algae and protists. The basal body is the base of the flagella inside of the cell that the external portion of the flagella is attached to.

Expansins

Growth of the primary wall requires a loosening of that wall, caused by proteins called expansins.

Cellulose Molecule Structures

Long string of glucose arranged in BETA fashion. (with OH alternating on opposite sides of each glucose in the line) this allows them to connect via loose hydrogen bonds to other beta glucose chains. (Alpha glucose have all of their OH's on one side)

Meiosis Vs Mitosis

Meiosis "make em individuals" Turns 2N into 1N.

Middle Lamella

Middle Lamella - the space between two plant cells - usually a layer of pectin (a strong jelly-like substance) which cements the two cells together. It is also the area where things and move between cells. Pectin is a thickening agent.

Enzymes

Molecules that help facilitate reactions. (they speed them up)

Plasmodesmata

Plant cells are connected to one another through plasmodesmata - transport tubes in which materials can flow through.

Plastids can change from one into another.

Protoplast can become amyloplast, chloroplast, chromoplast. Chloroplast can become chromoplast. Chromoplast can become chloroplast or amyloplast.

Protoplastids

Protoplastids - undifferentiated plastids that occur in merestemitic (dividing) cells of roots and shoots.

Ribosomes

Site of protein synthesis

Amyloplast

Synthesizes and stores starch

Mitochondria

Takes sugar and breaks it apart to make ATP. (the energy currency of the cell)

Cytoplasmic Streaming (Cyclosis)

The directed flow of cytosol (the liquid component of the cytoplasm) and organelles around large fungal and plant cells through the mediation of actin. Myosin molecules walk along the actin filaments by using energy released by ATP hydrolysis. Think of it like a whirlpool, that molecules float around in.

Parenchyma Cells

The most basic type of plant cell. General cell. It ss spherical and has a thin cell wall. -Carry out metabolism (respiration and photosynthesis) -Store compounds such s starch, and oils. Phloem are parenchymal cells that actively transport nutrients. Their cell parts shrink leaving a wide open lumen to be filled with sap.

Protoplast

The protoplast is all parts of the cell below the cell wall.

Plastids

They are double membraned organelles (likely became a part of plant cells through endosymbiosis - they were living on their own but were engulfed by a larger cell. Chloroplast has own DNA, has own ribosomes, divides by fission just like other bacteria). They're typically involved in food production and food storage. There are 3 types - chloroplasts, chromoplasts, and leucoplasts. Inside the plastid is a set of sacs called thlyakoids sitting in a matrix called stroma.

Tracheary Cells (Xylem)

They are tube-shaped and die at maturity. They have thick, strengthened cell walls (containing lignin) and have an empty lumen. Their function is to conduct water and minerals.

Glycoproteins

They're sugars attached to proteins. Structural proteins.

Thykaloid Grans

Thykaloid - flattened sacs inside of the plastid. grans - stacks of thykaloids. (looks like stack of pennies)

Vacuole Cell Sap

Vacuole - a membrane-bound organelle inside of a cell that stores a substance. Cell Sap - the liquid inside of the vacuole.

Waves, Cutin, Suberin

Waxy substances that are added to a cell wall, that form a waxy barrier blocking out water.

Carotenoid Pigments

Yellow-orange pigments found in chromoplasts. Generally they're not used for photosynthesis. Instead they're used to attract pollinators and seed dispersers.

Chloroplasts

an organelle inside of a plant cell containing chlorophyll - a green pigment, and caretenoids - a yellow pigment (typically masked by the green chlorophyll) which both help the cell capture light energy. These pigments are embedded on tkyaloid membranes inside of the chloroplasts.

Chloroplasts make sugar..._____ breaks it down.

mitochondria

Pith

parenchymal cells in the middle of the vascular tissue