genbio

Biology

Is the scientific study of life

Cell

Smallest unit of life

Unicellular

Consist of only a single cell

Multicellular

Contain hundreds, thousands, even trillions of cells

Metabolism

Sum of biochemical reactions occurring in an organism

Energy

Powers life processes

Heterotrophs

Organisms that get energy from the food they eat

Autotrophs

Organisms that use energy from the sun to make their own food

Photosynthesis

The process by which autotrophs make their own food

Homeostasis

Maintenance of a stable internal environment, even in face of a changing external environment

Reproduction

The production of offspring

Asexual Reproduction

Involves a single parent organism

Sexual Reproduction

Requires two parents

Genetic Code

Store genetic information in molecules of DNA

Biological Organization

Hierarchy of biological structures

Atom

Smallest particle

Molecule

Two or more atoms bonded together

Tissue

Group of similar tissues working together

Organ/Organ System

Group of similar organs working together

Organism

Complete multicellular individual

Population

Group of the same species in an area

Community

Group of different species in an area

Ecosystem

All biotic and abiotic factors in an area

Biome

Area of the planet classified according to the plants and animals that live in it

Biosphere

Global ecological system (earth)

Eukaryotic Cells

Have nuclei and other membrane-bound organelles

Cell Cycle

Complex sequence of events through which eukaryotic cells grow and reproduce

Mitosis

Process of cell division for somatic cells

Binary Fission

Type of asexual reproduction common in prokaryotic cells

Respiration

Breaks down fuel using oxygen and generates ATP.

Cell Transport

Movement of materials across cell membranes, including passive and active transport.

Passive transport

Does not require energy.

Active transport

Requires energy to proceed.

DNA Replication

An important cell process needed for chromosome synthesis and cell division.

Cell theory

The idea that cells are the basic unit of structure and function in every living thing.

Modern Cell Theory

States that energy flow occurs within cells, DNA is passed on from cell to cell, and all cells have the same basic chemical composition.

Robert Hooke

In 1665, he used a microscope to examine a thin slice of cork and described cells as tiny boxes.

Anton Van Leeuwenhoek

In 1673, he was the first to view living organisms under a microscope, calling them 'animalcules'.

Unicellular organisms

Made up of only one cell that carries out all the functions needed.

Multicellular organisms

Composed of more than one cell, with groups of cells differentiating to take on specialized functions.

Plasma membrane

Outer covering that separates the cell's interior from its surrounding environment.

Cytoplasm

Jelly-like region within the cell in which other cellular components are found.

DNA

Genetic material of the cell.

Ribosomes

Particles that synthesize proteins.

Flagella

Long fibers attached to the basal body of the cell that help in movement/locomotion.

Fimbriae

Small hair-like projections used to adhere to one another or to attach to cell surfaces.

Pili

Hair-like hollow attachment present on the surface of bacteria used to transfer DNA to other cells.

Glycocalyx

Outer viscous covering of fibers extending from the bacterium used for protection and adhesion.

Cell Wall

Extracellular structure that encloses the entire cell, including the plasma membrane, providing protection and maintaining shape.

Cell Membrane

Confines the contents of the cell to an internal compartment and regulates the flow of materials inside and outside the cells.

Mesosomes

Extension of cell membrane folded inward. Functions: Form a complex of membranes along which many of the cell's metabolic reactions take place.

Nucleoid

A limited region where the genetic material (DNA) is located.

Plasmid

Contains extrachromosomal DNA which are small, circular, and double-stranded molecules. Function: Carry genes that confer advantageous traits such as antibiotic resistance.

Inclusion Bodies

Tiny particles found freely suspended and floating within the cytoplasmic matrix. Function: Helps in storage of carbohydrates, glycogen, phosphate, fats in the form of particles which can be used when needed.

Endospore

A highly durable non-reproductive structure formed by certain bacteria. Function: Highly resistant to ensure survival and preserve the genetic information under environmental stress.

Eukaryotic Cell

DNA in a nucleus that is bounded by a membranous nuclear envelope. With membrane-bound organelles. Cytoplasm in the region between the plasma membrane and nucleus. Generally much larger than prokaryotic cells.

Cell Membrane

Membrane-boundary of the cell made up of a double layer of lipids with some proteins scattered throughout; the proteins form tiny openings. Function: Helps to maintain homeostasis by allowing certain substances to flow in and out of the cell 'selective permeability'. Provides protection and support. Gives cells their shape and flexibility. Communicates with other cells.

Cytoskeleton

A web of long tubes and fibers made of protein found throughout the cytoplasm. Made of three major types of protein filaments: microtubules, microfilaments, and intermediate filaments. Function: Supports the cell and helps the cell keep its shape. Helps certain cells move.

Microtubules

Hollow tubes made of subunits of tubulin protein. Provide structural support; have holes in cell and organelle movement and cell division; components of cilia, flagella, centrioles, basal bodies.

Intermediate filaments

Tough fibers made of protein. Help strengthen cytoskeleton; stabilize cell shape.

Nucleus

Found within the cytoplasm; separated from the cytoplasm by the nuclear membrane. Largest organelle made up of 3 parts: nuclear membrane, chromatin, and nucleolus. Function: Controls all the cell's activities-specifies cell protein.

Chromatin

Thin threadlike structures made up of DNA; contains genes that control cell activities and provides the information to the ribosomes to make proteins.

Nucleolus

A granular body within nucleus; consists of RNA and protein; site of ribosomal RNA synthesis.

Ribosomes (Eukaryotes)

Granules composed of RNA and protein; some attached to ER, some free in cytosol. Function: Gets instructions for protein production from the DNA in the nucleus. Eukaryotes have 80S ribosomes which are further divided into two subunits - 40S and 60S (S stands for Svedberg unit).

Endoplasmic Reticulum

Network of folded tube-like internal membranes extending from the nuclear membrane to the cell membrane. Rough ER has ribosomes on the outer surface. Smooth ER lacks ribosomes.

Golgi Apparatus

Sort and modify proteins from the ER to do different jobs; these are then packaged in sacs (called vesicles) that break off the end of the stack; vesicles go.

Mitochondria

Rod-shaped structures that have a folded inner membrane within an outer membrane; scattered throughout cytoplasm. Release energy from the sugar (glucose) in food by combining it with oxygen (cell respiration); it stores this energy in special energy-rich molecules (called ATP) that the cell uses to do its work. The 'powerhouse' of the cell.

Lysosome

Small, round structures filled with digestive enzymes. Break down large food molecules into small ones so they can enter the mitochondria. Digest waste products, worn out organelles, and dead or injured cells to make room for new cells. Protect the cell from foreign invaders.

Peroxisomes

Membranous sacs containing a variety of enzymes. Site of many diverse metabolic reactions; e.g., break down fatty acids. The enzymes in peroxisomes are synthesized by free ribosomes and transported into a peroxisome from the cytoplasm.

Vacuole

Large membranous sacs (mostly in plants, fungi, algae) filled with fluid. Storage area for food, water, wastes, and other materials. When plant vacuoles are completely filled with water, the cells are pumped and the plant is firm; if it loses water, the plant wilts.

Chloroplast

Large oval-shaped double-membrane structure enclosing internal thylakoid membrane; chloroplasts contain chlorophyll in thylakoid membrane. Chloroplast is a site of photosynthesis, captures light energy; ATP and other energy-rich materials are produced and then used to convert carbon dioxide to carbohydrate.

Centrosomes

Found in cytoplasm; close to the nucleus, consist of two centrioles. Major microtubule-organizing center for the cell. Direct the movements of microtubes and other cytoskeletal structures and proteins allowing changes to the shapes of animal cell membranes.

Appendages

Cilia and flagella are locomotory attachments, which help in the movement of a cell towards positive stimuli. Cilia are shorter than flagella and numerous.

Animal cell

Do not have plastids.

Plant cell

Have plastids (e.g., chloroplast).

Prokaryotic cell

Small cells.

Cell Modification

A process that occurs after cell division where the newly formed cells are structurally modified so that they can perform their function efficiently and effectively.

Meristematic tissues

Plants can grow continuously due to the activity of meristems, unspecialized tissues composed of dividing cells.

Dermal tissue

Forms the outer protective covering of a plant.

Ground tissue

Fills the interior of a plant.

Vascular tissue

Transports water and nutrients within the plants as well as providing support.

Apical meristems

Located at the tips of roots and shoots, elongate shoots and roots, a process called primary growth.

Lateral meristems

Add thickness to woody plants, a process called secondary growth.

Intercalary meristem

Located at the internodes or the base of the leaves, occurs only in monocots, particularly grass.

Guard cells

Facilitate gas exchange in shoots.

Parenchyma

Most abundant type of plant tissue found in all organs but at least specialized.

Collenchyma

Provide support and flexibility to immature regions of a plant body by forming bundles just beneath the epidermis.

Sclereids

A type of plant tissue.

Xylem

Conducts water and dissolved minerals upward from roots into the shoots.

Phloem

Transports sugars from where they are made (primarily leaves) to storage structures or sites of growth.

Epithelial tissue

Covers the outside of the body and lines the organs and cavities within the body. Contains cells that are closely joined.

Connective tissue

Sparse cells in the extracellular matrix. Binding and support of other tissues.

Muscle tissue

Long cells (fibers) with contractile proteins. Movement of body parts

Nervous tissue

Neurons with branching extensions. Transmission of nerve signals.

Cuboidal cells

Epithelial cells that are shaped like dice.

Columnar cells

Epithelial cells that are shaped like bricks on end.

Squamous cells

Epithelial cells that are shaped like floor tiles.

Simple epithelial

A single cell layer of epithelial cells.

Stratified epithelial

Multiple tiers of epithelial cells.

Pseudostratified epithelial

A single layer of epithelial cells of varying length.