GEN BIO 12 FULL MIDTERM REVIEWER (copy)

Biology

The study of living things, including animals, plants, and microorganisms, and their life processes such as gathering and using energy, adapting and evolving, reproducing, and interacting with the environment.

Cell

The basic unit of life, which makes up all living things and is a microscopic membrane-bound system that controls the chemicals and molecules necessary for an organism's existence.

Cell Theory

The fundamental principles of biology that state that the cell is the basic unit of life, all living organisms are composed of cells, new cells are created from pre-existing cells, and cells of multicellular organisms are interconnected.

Microscope

A scientific tool used to magnify objects that cannot be seen by the naked eye, and is essential in the study of the fine structure of organisms, especially cells.

Cell Membrane

The outermost part of the cell that acts as a gatekeeper, controlling the entry and exit of materials into and out of the cell, and is composed of a phospholipid bilayer held together by van der Waals force.

Cytoplasm

The jelly-like substance inside the cell that contains various organelles and is the site of many cellular processes.

Nucleus

The central part of the cell that contains the genetic material (DNA) and controls the cell's activities.

Metabolism

The sum of all chemical reactions that take place inside a living cell or organism, including anabolism (building up) and catabolism (breaking down) of substances.

Reproduction

The process by which organisms produce offspring, ensuring the continuation of their species.

Genetic Material

The DNA contained within the cells of all organisms, which carries the instructions for the development, functioning, and reproduction of the organism.

Cell Wall

A rigid wall found in plant and bacterial cells which lies outside the cell membrane. Serves as secondary wall for plant and bacterial cells.

Cytoplasm

The area in the cell where the organelles are located. Composed of water, proteins, and salts. The liquid portion of the cytoplasm is known as cytosol. Contains enzymes that break down waste and enable metabolic reactions.

Cytoskeleton

Helps maintain the structure of the cell and is present in all cells.

Endoplasmic Reticulum

Responsible for transporting molecules across the cytoplasm and is also capable of assembling new lipids for export to other cells. There are two types of ER:rough or granular endoplasmic reticulum, which synthesizes and modifies proteins, and smooth or agranular endoplasmic reticulum, which synthesizes fatty acids and phospholipids.

Ribosomes

Site of protein synthesis. Present in both prokaryotic and eukaryotic cells. Some are attached to the rough endoplasmic reticulum, while others freely swim around the cytoplasm. Free ribosomes synthesize proteins mostly for use within the cell, while bound ribosomes synthesize proteins for export or use in lysosomes.

Vacuole

A fluid-filled vesicle enclosed by a membrane. This organelle stores chemicals within the cell.

Lysosome

Known as the "suicide bag" of the cell. Serve as digestion slots for cellular materials that are due for expiration or are no longer useful.

Golgi Apparatus

A system of irregular network of canals which functions as the manufacturer and the shipping center of the cell. It modifies, sorts, and packages the macromolecules synthesized by the cell.

Mitochondria

Powerhouse of the Cell. Serves as the site for cellular respiration. Mitochondrion has the responsibility to produce ATP (adenosine triphosphate) which is the energy of the cell.

Chloroplast

An organelle that can only be found in plants and photosynthetic protists. Serves as the site of energy conversion in plants. Contains the green pigment of the plant called chlorophyll.

Centrioles

Small cylindrical dark bodies, which occur in pairs hence sometimes called diplosome. Found outside the nucleus. Plays a major role in the formation of spindle fibers during cell division.

Nucleus

A spherical structure usually located near the center of the cell and enclosed by the nuclear membrane. It is the control center of the cell.

Nuclear Membrane

Double-layer membrane that envelopes the nucleus.

Nuclear Pores

Perforated holes in the nuclear membrane that permit the movement of selected molecules between the nucleus and the rest of the cell, while blocking the passage of other molecules.

Nucleoli

Site of synthesis of RNA and protein.

Chromosomes

Rod/thread-like structure carrying genes.

Gene

Basic unit of heredity and consists of a specific sequence of DNA or RNA.

DNA

Contains the genetic code.

Prokaryotic Cells

A cell with no definite or distinct nucleus. No membrane-bound organelles. Circular chromosome. No nuclear membrane. Has a cell wall and cell membrane. Found in bacteria.

Eukaryotic Cells

A cell with a definite or true nucleus. Has membrane-bound organelles. Its genetic material is enclosed in the nucleus. Structurally more complex.

Microvilli

Finger-like extensions that increase the surface area of the cell.

Flagella

Tiny whip-like structure that allows a cell to move.

Cilia

Tiny thread-like projections.

Pili

Slender hair-like extensions for attachment.

Plastids

Chloroplasts contain green pigment (chlorophyll). Chromoplasts contain yellow, red, and blue pigments. Leucoplasts are colorless plastids that contain organic substances such as oil, starch, and protein.

Meristematic Tissues

Consist of immature and undifferentiated cells. Regions of active cell divisions. Responsible for the increase in the height and width of the plant.

Terminal or Apical Meristem

Specialized tissues located at the growing points. Responsible for the increase in the height of the plant (primary growth).

Intercalary Meristem

Meristematic tissues found at the internodal region of the stem. Responsible for the increase of primary growth of plants. Disappear and transformed into permanent tissues.

Lateral Meristem

Meristem tissues found on the side of stems and roots. Responsible for the increase in girth or diameter of the plant body (secondary growth).

Surface Tissues

Tissues found in the outermost layer or covering of the plant body. Includes epidermis, cork, and stomata or guard cells. Serves as protection for the plants.

Fundamental Tissues

Basic tissues of any plant. Found in any organ of the plant. Includes parenchyma cells, collenchyma cells, and sclerenchyma cells.

Parenchyma Cells

Thin primary cell wall. Large centrally located vacuole. Thin cytoplasm. Contains chlorenchyma. Site for manufacturing food and storage of the product.

Collenchyma Cells

Cells with irregularly thickened primary wall. Strengthening and supporting.

Sclerenchyma Cells

Cells with heavily thickened cell wall due to the presence of lignin. Primary and secondary walls are present. Responsible for the strengthening and support of the plant. Usually forms in the skin of fruits.

Vascular Tissues

Conducting tissues of plants responsible for the transport of water and food inside the plant body.

Phloem

Responsible for the downward conduction of food in plants.

Xylem

Responsible for the upward conduction of water and minerals in plants.

Epithelial Tissue

Composed of closely packed cells found covering the surface of the body and lining the cavities of hollow organs.

Squamous Epithelial Tissue

Flattened cells located in the epidermis of the skin, pleura, pericardium, alveolus, and bowman's capsule.

Cuboidal Epithelial Tissue

Cube-like cells found in the collecting tubules of the kidney.

Columnar Epithelial Tissue

Tall and thin cells found in the oviduct, intestine, and stomach.

Simple Epithelial Tissue

Epithelial tissue with one layer.

Stratified Epithelial Tissue

Epithelial tissue with one or more layers.

Pseudostratified Epithelial Tissue

Epithelial tissue with false layers.

Connective Tissue

Most diverse and widespread tissue in the body, responsible for protection, support, connection, and binding.

Dense Connective Tissue

Connective tissue with fibers as its main matrix element, including dense regular, dense irregular, and dense elastic connective tissue.

Loose or Areolar Connective Tissue

Connective tissue with fewer cells and protein fibers, abundant in viscous ground substance.

Adipose Tissue

Connective tissue that stores energy and insulates organs, composed of fat cells.

Blood Tissue

Connective tissue composed of erythrocytes, leukocytes, and thrombocytes.

Supportive Connective Tissue

Connective tissue responsible for giving support to the human body, including bone and cartilage tissue.

Skeletal Muscle

Muscular tissue attached to the bone, voluntary and striated.

Smooth or Visceral Muscle

Muscular tissue found inside internal organs, involuntary and non-striated.

Cardiac Muscle

Muscular tissue found on the walls of the heart, involuntary and striated.

Nervous Tissue

Specialized tissue that responds to stimuli and transmits impulses, composed of neurons and glial cells.

Neuron

Nerve cell responsible for transmitting impulses, including cell body, dendrites, axon, Schwann cells, myelin sheath, node of Ranvier, axon terminal, and synapse.

Sensory Neuron

Nerve cell that receives information from the environment and sends it to the brain.

Motor Neuron

Nerve cell allocated in the muscle that receives information from the brain and spinal cord to make the muscle contract or act.

Interneuron or Associative Neuron

Nerve cell allocated inside the brain and spinal cord connecting sensory neurons and motor neurons.

Cell Division

Mitosis & Meiosis:Processes of cell multiplication.

Chromosomes

Visible thread-like structures that bear the genetic information of an organism.

Homologous Chromosomes

Pair of chromosomes, one inherited from the male parent and the other from the female parent.

Genetic Locus

Location of a particular gene on a chromosome.

Deoxyribonucleic Acid (DNA)

Double helix organic molecule that carries genetic information.

Chemical component of DNA

Deoxyribose sugar

Chemical component of DNA

Phosphate group

Chemical component of DNA

Nitrogen base

Hydrogen bond

A weak bond that holds the two strands of DNA together

Diploid status (2n)

When the number of chromosomes in a cell is 46

Haploid status (n)

When the number of chromosomes in a cell is reduced to 23

Chromatin

Thread-like form of chromosomes during the G1 phase of the cell cycle

Sister chromatids

Replicated DNA joined by a common centromere during the S phase of the cell cycle

Histones

Highly alkaline proteins that package and order DNA into structural units called nucleosomes

Interphase

The stage of the cell cycle where the cell grows and carries out its usual metabolic activities

Cell division

The stage of the cell cycle where the cell reproduces itself through processes like mitosis and meiosis

Growth 1 phase (G1)

The first stage of interphase where the cell recovers from cell division and carries out normal metabolic activities

Synthesis phase (S phase)

The second phase of interphase where the genetic material is doubled through replication

Growth 2 phase (G2)

The last stage of interphase where the cell prepares for division by doubling all organelles

Mitosis

The division of body/somatic cells, excluding gametes, that occurs during embryonic development, growth, repair, and tissue replacement

Prophase

The first stage of mitosis where chromosomes start coiling, centrosomes migrate, nucleolus disintegrates, and nuclear membrane disappears

Metaphase

The second stage of mitosis where chromosomes align along the equatorial plate/metaphase plate under the direction of spindle fibers

Anaphase

The third stage of mitosis where sister chromatids separate and move to opposite poles guided by spindle fibers

Telophase

The fourth stage of mitosis where cytoplasmic division and nuclear reconstruction occur, chromosomes relax and uncoil, and two new diploid cells are formed

Meiosis

A type of cell division that occurs in reproductive cells, resulting in the reduction of the number of chromosomes to form haploid gametes

Prophase I

The first stage of meiosis where chromosomes become thicker, nuclear membrane disappears, and events like synapsis and crossing over occur

Metaphase I

The second stage of meiosis where bivalents align on the metaphase plate and spindle fibers form

Anaphase I

The third stage of meiosis where homologous chromosomes separate and move to opposite poles

Telophase I

The fourth stage of meiosis where chromosomes are still doubled, nuclear membrane reappears, and spindle fibers disappear

Prophase II

The first stage of the second meiotic division where the nuclear envelope breaks down and the spindle apparatus forms

Metaphase II

The second stage of the second meiotic division where chromosomes align at the metaphase plate and centromeres divide

Anaphase II

The third stage of the second meiotic division where separated chromatids move to opposite poles