Chloroplast and Nucleus Lecture Notes

Vocabulary flashcards covering the structural components of chloroplasts, types of plastids, and the detailed anatomy/history of the cell nucleus.

Stroma

The fluid surrounding the thylakoids that contains ribosomes and a small circular DNA; it is the part of the chloroplast where carbon dioxide is fixed to manufacture sugar.

Thylakoids

Flattened vesicles that arrange themselves into stacks to form grana.

Granum

A structure appearing as a pile of $50$ or more thylakoids stacked like coins, which appears green due to chlorophyll molecules arranged on the layers.

Intergranum

The non-green part of the chloroplast that interconnects one granum with another.

Chromoplasts

Organelles that impart color to plant parts other than green, such as flower petals and ripened fruits, aiding in pollination and seed dispersal.

Leucoplasts

Colorless plastids of various shapes (triangular or tubular) found mostly in underground plant parts used to store food.

Robert Brown

The person who reported the presence of the cell nucleus in $1838$.

Nucleus

An organelle typically about $10\,\mu{m}$ in diameter that controls metabolic activities and contains genetic information in the form of chromosomes and DNA.

Mono-nucleate

Cells that contain only one nucleus.

Bi-nucleate

Cells that contain two nuclei.

Multi-nucleate

Cells that contain more than two nuclei.

Nuclear membrane

Also called the nuclear envelope, it is composed of two membranes: an outer membrane continuous with the Rough Endoplasmic Reticulum (RER) and an inner membrane enclosing the nuclear contents.

Nuclear pores

Openings in the nuclear membrane that allow for the exchange of materials between the nucleus and the cytoplasm.

Nucleolus

A darkly stained, non-membranous body within the nucleus where rRNA (ribosomal RNA) is synthesized and stored.

Peripheral granular area

A region within the nucleolus composed of the precursor of ribosomal subunits.

Central fibrillar area

A region within the nucleolus consisting of rDNA and large molecular weight RNA.

Nucleoplasm

A colloidal mixture of organic and inorganic salts and ions that serves as a matrix for chromatin and stores enzymes and raw materials for DNA replication and RNA synthesis.

Waldeyer

The biologist who used the term chromosome in $1888$.