GENERAL BIOLOGY 1: SEM2 MIDTERM

Robert Hooke

devised the earliest microscope that can magnify materials

Antoine Van Leeuwenhoek

first to study magnified cells & invented simple microscope with 1 lens

Matthias Jakob Schleiden

focused on the study of plant cells

Theodor Schwann

focused on the study of animal cells

Rudolf Carl Virchow

stated that all cells come from other cells through the process of cell division

Cell Division

fundamental process when a parent cell divides into 2 or more daughter cells

Mitosis

a cell division process that occurs in somatic (body) cells, producing 2 genetically identical cells

Meiosis

a cell division process that occurs in germ (sex) cells, producing 4 genetically unique cells

Organic Cell Evolution

a hypothesis that states life originated from primitive cells (protocells) from inorganic & organic molecules in Earth’s prebiotic oceans

Protocells

formed by the polymerization of organic molecules in heated rocks or clay

Aleksandr Oparin

proposed that organic molecules might have been assembled in Earth’s primitive atmosphere in the presence of strong energy

Stanley Miller

designed an experiment to test Oparin’s hypothesis, but was disproven because their setup lacked oxygen

Miller-Urey Experiment

mixture of inorganic compounds in a closed system that resembled the strong reducing atmosphere of primitive Earth

Prokaryotic Cell

simple organisms possessing cells that are smaller in size with simple structures

Plasma Membrane

present in prokaryotic cell — semi-permeable membrane that allows waste to pass through & prevents diffusion of essential products to the external environment

Cell Wall

present in prokaryotic cell — rigid wall that maintains shape especially in high water influx

Capsule

protective layer of polysaccharides lying outside the cell wall

Nucleoid Region

present in prokaryotic cell — irregular-shaped region that houses genetic material (DNA)

Cytoplasm

present in prokaryotic cell — makes up cell’s internal environment; not organized into distinct interior compartments

Mesosome

folded invagination of the plasma membrane

Ribosome

site for protein synthesis

Plasmid

independent circular DNA structures, providing anti-bacterial resistance

Flagellum

tail-like appendage for locomotion of 360° rotation, propelling the bacteria

Fimbriae

smaller bristle-like fibers over the surface, helping to attach to surfaces

Conjugation Pili

tubular structures for cell-to-cell communication & pass DNA

Eukaryotic Cell

complex type of cell possessed by fungi, plants, animals & protists

Eukaryotic Cell

cells are membrane-bounded compartments & organelles are neatly arranged

Cell Membrane

present in eukaryotic cell — gatekeeper that regulates the passage of molecules, ions & gases in & out of the cell; secures the cell’s content

Phospholipid Molecule

contains a charged phosphate group, glycerol & 2 fatty acid chains

Phospholipid Head

polar molecule (can join H bonds with H2O molecules) that contains the glycerol & phosphate group; hydrophilic

Phospholipid Tail

non-polar molecule that consists of fatty acids; hydrophobic

Cholesterol

a cell membrane structure that strengthens cell membrane by making it more flexible & less fluid

Carbohydrates

a cell membrane structure that are identification tags, enabling cells to distinguish 1 type of cell from another

Transport Protein

proteins that extend from phospholipid bilayer to help materials cross the membrane

Channel Protein

proteins that form tunnels that help cells import or export needed materials & expel waste

Cell Recognition Protein

proteins that distinguish own cells from other organisms like pathogens

Enzymatic Protein

proteins that participate in metabolic reactions

Catabolic (Degenerative) Reactions

metabolic reaction that breaks down molecules into simpler ones, releasing energy

Anabolic (Synthetic) Reactions

metabolic reaction that builds complex molecules from simpler ones, requiring energy

Cytoskeleton Protein

proteins that act as muscle & skeleton to maintain cell shape & motility

Junction Protein

proteins that assist in cell-to-cell adhesion & communication between cells

Receptor Protein

proteins that exchange of signals with other cells by changing shape to allow a specific molecule, the ligand, to bind with it

Passive Transport

a cell transport that does not require any energy & moves with concentration gradient (high to low)

Simple Diffusion

a passive transport that allows some molecules (smaller) to easily pass through the bilayer

Facilitated Diffusion

a passive transport that uses the help of transport proteins to enter the cell, such as polar or large molecules like glucose & charged ions

Active Transport

a cell transport that forces molecules to go against their concentration gradient (low to high) that energizes the transport protein itself

Adenosine Triphosphate

energy present in a cell that is used when a cell tries to undergo active transport

Endocytosis

occurs in active transport — the fusing of molecules with the cell membrane to form vesicles that can be taken inside the cell

Phagocytosis

occurs in endocytosis — when it stretches out & pulls it in a vacuole

Receptor-mediated Cytosis

occurs in endocytosis — when it has to bind with the receptors

Pinocytosis

occurs in endocytosis — when it takes in fluids

Exocytosis

occurs in active transport — gets rid of cell waste by getting valuable materials that need to be used out of the cell

Cell Wall

present in eukaryotic cell — additional boundary that provides support, protection & shape to the cell

Polysaccharide Cellulose

a fibrous carbohydrate present in plants & algae

Chitin

strong carbohydrate as the building of an exoskeleton, present in fungi

Peptidoglycan

polymer of amino acid & sugar present in bacteria

Primary Cell Wall

a plant cell wall that is thin & flexible wall that allows cell growth, mainly made of cellulose

Secondary Cell Wall

a plant cell wall that is thick & strong wall that forms inside of the primary cell wall after growth & contains cellulose, lignin & hemicellulose — for mechanical support

Gram-Positive Bacteria

a bacterial cell wall that is a thick layer of peptidoglycan, retains crystal violet stain — less resistant

Gram-Negative Bacteria

a bacterial cell wall that is thin layer of peptidoglycan & an outer membrane, does not retain crystal violet stain; protects bacteria from anti-bodies — resistant

Cytoplasm

present in eukaryotic cell — fills the space between nucleus & cell membrane

Cytosol

the fluid portion consisting mainly of water & excluding the organelles in it

Nucleus

storehouse of genetic information in the form of DNA

Nucleus

directs all activities of the cell following the DNA instruction

Nucleus

protects DNA from damage & its instruction must be available for use at all times

DNA

long chain of molecules that can be segmented into genes

DNA

containing instructions for making proteins

Nucleolus

dense region where small organelles essential for making proteins (ribosomes) are assembled

Endoplasmic Reticulum

interconnected network of folded membranes arranged like a maze

Lumen

the interior of the maze as the sites for production of proteins & lipids

Rough ER

has ribosomes attached to its surface that join with amino acids to form proteins

Smooth ER

responsible for the production of lipids & breaking down drugs & alcohol

Golgi Apparatus

layered stack of membrane-enclosed spaces where proteins are processed, stored & delivered — possessing enzymes that modify proteins

Vesicles

part that cannot work without the help of other organelles where manufactured proteins from a part of the ER pinched off, form small-membrane bound sacs that enclose the proteins

Vesicles

short-lived & recycled as needed by the cell — may develop into lysosomes or vacuoles

Vacuoles

fluid-filled sacs for storage of materials needed by cells like water, food molecules, inorganic ions & enzymes

Central Vacuole

single large vacuole that takes up most space in plant cells with a watery fluid that strengthens the cell & supports shape

Lysosomes

round-shaped membrane-bound structure that contains chemicals that can break down materials in the cell — more present in animal cells

Lysozyme

enzyme that defends the cell from invading bacteria & viruses; helps break down damaged & worn-out cell parts — the “suicide” part of the cell

Peroxisomes

small vesicles around the cell surrounded by a single membrane that contains digestive enzymes for breaking down toxic materials

Peroxisomes

carries oxidative enzymes that require oxygen & are more present in the liver as they help break down alcohol

Mitochondria

the powerhouse of the cell that supplies energy & has its own ribosomes & DNA

Mitochondria

a round/oval shaped organelle with 2 membranes

Mitochondria

creates a series of chemical reaction that converts molecules from the food eaten into usable energy

Plastids

contain chloroplasts that help a plant convert solar energy to chemical energy, carrying out photosynthesis & has its own ribosomes & DNA

Thylakoids

membranes within the chloroplasts that contain chlorophyll — light-absorbing pigment that gives plants the green color

Granum

stacks of thylakoids inside the chloroplast

Stroma

the liquid portion of the chloroplast

Centrosome

dense region of the cytoplasm that serves as the main microtubule organizing center

Centriole

cylinder-shaped organelles made of 9 triplets of short microtubules arranged in a ring

Cilia

hair-like locomotory projections

Cytoskeleton

framework of flexible network of small protein subunits, forming long threads of fibers that crisscross the entire cell

Microtubules

lengthy & thick; gives cell shape & serves as an anchorage for other cell parts

Intermediate Filaments

rope-like, smaller; provides tensile strength to stretch out without breaking

Microfilaments

thinnest known as actin filaments; provides mesh work under plasma membrane

Cell Junctions

structures that connect cells to form tissues & allow coordinated function

Plasmodesmata

shares water, nutrients & chemical messages among plants

Tight Junction

a cell junction where 2 cells tightly together to form a leak-proof sheets

Adhesion Junction

a cell junction that acts like screws together with cytoskeletal fibers to form strong sheets