Biological Levels of Organization and Virology

Vocabulary flashcards covering biological levels of organization, organ systems, cellular structures, leaf anatomy, and the differences between cells and viruses.

Cell

The basic unit of all living things and the smallest level of biological organization that can support all the characteristics and functions of life.

Tissue

A group of similar cells working together to perform a specific job for the body.

Organ

A level of biological organization made of different types of tissue coming together to perform a specific job for the body.

Organ System

A group of many different organs working together to perform a major job for the body, such as digesting food.

Organelle

A specialized structure within a cell, made of many molecules put together, that carries out a specific role.

Biological Levels of Organization

The structural hierarchy of living organisms from smallest to largest: $\text{Atom} \rightarrow \text{Molecule} \rightarrow \text{Organelle} \rightarrow \text{Cell} \rightarrow \text{Tissue} \rightarrow \text{Organ} \rightarrow \text{Organ System} \rightarrow \text{Organism}$.

Four Main Human Tissue Types

Muscle tissue, nervous tissue, connective tissue, and epithelial tissue.

Mitochondria

The organelle that generates energy for the cell.

Ribosome

The organelle that builds proteins for the cell.

Neuron

A nerve cell responsible for receiving, processing, and transmitting messages through electrical and chemical signals.

Neuronal Network

A term used to describe many neurons working together.

Cardiac Tissue

A specialized type of muscle tissue that forms the heart, working alongside nervous tissue to pump blood throughout the body.

Brain

The main organ of the nervous system.

Heart

The main organ of the circulatory system.

Digestive System Organs

The series of organs making up the digestive system: mouth, pharynx (throat), esophagus, stomach, small intestine, large intestine, and rectum.

Leaf Tissue Layers

The structural tissue layers in a plant leaf, which include the cuticle, epidermis, palisade mesophyll, spongy mesophyll, veins (xylem and phloem), guard cells, chloroplasts, and stoma.

Virion

An inert, inactive virus particle located outside of a living host cell.

Metabolism

The total of all chemical reactions occurring within a cell.

Cytoplasm

The liquid 'soup' of nutrients, enzymes, and metabolic products present in all cell types.

Universal Cell Features

The four common features found in all cells: cytoplasm, cell membrane, DNA, and metabolism.

Cell vs. Virus Differences

Cells are larger ($100\,000\,nm$ vs. $50\,nm$), have organelles, possess metabolism, contain DNA, and reproduce independently; viruses lack organelles and metabolism, contain DNA or RNA, and require a host cell to reproduce.

Purpose of Body Organization

Careful organization allows body parts to specialize in specific jobs, working together to maintain homeostasis, function efficiently, and survive.