PH-BPS 112 Unit 2: Plant Structures Part 1 Flashcards

This set covers vocabulary and structural components of plant cells as well as the phases of the plant cell cycle based on lecture notes.

Protoplasm

Consists of all the living components of a cell.

Plasma membrane

The outer boundary of the living part of the cell, consisting of a double layer of lipids (phospholipids with a hydrophilic phosphate head and 2 hydrophobic fatty acid tails).

Cytoplasm

All cellular components between the plasma membrane and the nucleus.

Cytosol

The soup-like fluid where the organelles are dispersed within the cell.

Cell Wall

The most obvious plant cell structure that defines the shape of the cell; made mainly of cellulose but also consists of hemicellulose, pectin, and glycoproteins.

Nucleus

The control center of the cell, bounded by a nuclear envelope (two membranes) and appearing as a grayish, spherical to ellipsoidal lump.

Nucleoplasm

The granular-appearing fluid contained within the nucleus.

Endoplasmic Reticulum (ER)

Facilitates cellular communication and channeling of materials; manufacturing sites for lipids and many proteins.

Rough ER

Endoplasmic reticulum present in cells specializing in production of proteins; characterized by membrane-bound ribosomes.

Smooth ER

Endoplasmic reticulum specializing in lipid production and detoxification; more tubular and not studded by ribosomes.

Ribosomes

Sites of protein synthesis composed of 2 subunits made of RNA and proteins; they do not have membranes.

Dictyosomes

Collecting, packaging, and delivery centers of the cell; they modify carbohydrates attached to proteins and help build new primary walls in dividing cells.

Plastids

Energy transducing cell organelles found only in plants; includes chloroplasts, chromoplasts, and leucoplasts.

Chloroplasts

Plastids containing stroma (colorless fluid matrix) and grana (which contain thylakoids).

Chromoplasts

Plastids that are yellow, orange, or red in color due to carotenoid pigments.

Leucoplasts

Colorless plastids common to higher plants, including amyloplasts and elaioplasts.

Mitochondria

The powerhouse of the cell; responsible for the release of energy from organic molecules via cellular respiration.

Cristae

Plate-like folds within mitochondria that increase the surface area available to enzymes.

Peroxisomes

Smallest membrane-bound organelles (microbodies) that metabolize hydrogen peroxide, primarily in leaves.

Glyoxysomes

Microbodies in germinating oil-bearing seeds with enzymes that catalyze the breakdown of fatty acids into acetyl CoA.

Cell sap

The watery fluid filling vacuoles that maintains pressure and contains salts, sugars, organic acids, proteins, and water-soluble pigments like anthocyanins.

Tonoplasts

Also known as vacuolar membranes, these constitute the inner boundaries of the living part of the cell.

Cytoskeleton

A network of filaments (microtubules and microfilaments) that forms a mechanical support system for the cell and involves cell architecture and movement.

Microtubules

Cytoskeleton fibers that control the addition of cellulose to the cell wall and are involved in cell division and the movement of flagella and cilia.

Microfilaments

Cytoskeleton fibers that play a role in the movement of cells in multicellular animals and are important in cytoplasmic streaming (cyclosis).

Plasmodesmata

Specialized junctions where holes in the cell wall allow direct cytoplasmic exchange between two cells.

Zygote

The first dividing cell in the life history of the plant, formed from the union of sperm and egg.

Meristems

Specialized regions in the pre-embryo capable of undergoing cell division.

Interphase

The longest period of the cell cycle where meristematic cells spend $90\%$ of their time; consists of intervals known as Gap 1, Synthesis, and Gap II.

Gap 1 ($G_1$)

Phase beginning immediately after a nucleus divides; the cell increases in size and produces ribosomes, RNA, and substances for the following S period.

Synthesis ($S$)

The phase of the cell cycle where DNA replication (duplication) takes place.

Gap II ($G_2$)

Phase where mitochondria and other organelles divide, and coiling and condensation of chromosomes begin.

Mitosis

The process of cell division initiated with a pre-prophase band of microtubules; consists of Prophase, Metaphase, Anaphase, and Telophase.

Prophase

Phase where chromosomes condense into rod-like configurations, the nuclear envelope fragments, and the nucleolus disintegrates.

Metaphase

Phase where chromosomes, composed of paired chromatids, align in a circle midway between the two poles.

Anaphase

The briefest phase of mitosis where sister chromatids separate and are pulled toward opposite poles as daughter chromosomes.

Telophase

Phase where a nuclear envelope reforms around each group of daughter chromosomes, nucleoli reappear, and a cell plate forms.

Cytokinesis

The final step of cell division where a cleavage furrow deepens to partition the cytoplasm of a mother cell into two daughter cells.