Biology Review Flashcards

Flashcards covering key terms and concepts from the Biology lecture notes, including cell structure and cycling of matter in living systems.

Biology

The study of life, described from micro to macro levels.

Levels of Biological Organization

Molecules to organelle to cell to tissue to organ to organ system to organism to population to community to ecosystem to biosphere.

Abiogenesis

The theory that organisms can arise spontaneously.

Biogenesis

Reddi disproved it. Idea that new organisms come from pre-existing organisms.

Francesco Redi (1668)

Disproved spontaneous generation with his experiment involving meat, flies, and maggots.

Pasteur (1864)

Used an S-bend flask to allow air but not microorganisms to reach broth, disproving spontaneous generation.

Controlled Variables in Pasteur's Experiment

Light, temperature, broth type, flask type.

Manipulated Variable in Pasteur's Experiment

Access to air.

Responding Variable in Pasteur's Experiment

Growth of mold.

Leeuwenhoek

Discovered the microscope (~1680)

Hooke

Observed cork cells (~1680).

Cell Theory

All organisms are made of cells; all plants and animals come from cells; the cell is the basic unit of life; new cells come from pre-existing cells.

Three tasks accomplished by a Microscope

Produced a magnified image of the specimen, separate the details in the image, and render the details visible to the human eye or camera.

Simple Microscope

Light passes through only one lens; example: magnifying glass.

Compound Microscope

Lets light pass through an object and then through two or more lenses.

Stereoscopic (Dissecting) Microscope

Gives a three-dimensional view of an object; used for dissections.

Contrast in Microscopy

Cells appear colorless when light passes through. Staining fixes this, but kills the cells.

Resolution (Resolving Power)

The ability to distinguish between two structures that are very close together.

Electron Microscope

Uses a beam of electrons instead of light to magnify the image.

Scanning Electron Microscope (SEM)

Produces a 3D image of a specimen's surface features by bouncing electrons off a surface covered with electron-dense material.

Transmission Electron Microscope (TEM)

Allows observation of molecules within cells and magnification of objects in the order of 100,000s; provides a 2D view.

Confocal Laser Scanning Microscope (CLSM)

Uses a laser beam to illuminate spots on a specimen, and a computer compiles images to generate a 3D image; used on thick specimens.

Scanning Tunneling Microscope

Can resolve the bump caused by a single iron atom.

Microscope Magnification

An increase in the apparent size of an object, calculated as the product of the magnifying powers of the objective lens and the eyepiece.

Field of View

Area that can be seen through the microscope with a given objective lens.

Cell Theory

All organisms are composed of one or more cells; cells are the smallest living units; cells come from pre-existing cells.

Prokaryote Cell

No nucleus, single loop of DNA, few organelles; bacteria.

Eukaryote Cell

Enclosed nucleus, DNA in chromosomes, many organelles; plants, animals.

Cytoplasm

A jelly-like substance that supports the organelles inside a cell.

Cell Membrane

Encloses the cell contents; phospholipid bilayer with embedded proteins.

Nucleus

Contains genetic material (DNA); directs activities of the cell.

Nucleolus

Site of ribosome assembly.

Chromosomes

DNA of eukaryotes is densely packed into these structures.

Endoplasmic Reticulum (ER)

Serves as a system of channels from the nucleus for transport.

Rough ER

Has ribosomes attached (sites of protein synthesis).

Smooth ER

Lacks ribosomes.

Golgi Apparatus

Collect, package, and distribute molecules synthesized at one location in the cell and utilized at another location.

Lysosomes

Membrane-bound vesicles containing digestive enzymes; break down food particles and destroy old, worn-out cell parts.

Ribosomes

Site of protein synthesis; assembled in the nucleolus of the cell.

Mitochondria

Site of cellular respiration; converts stored energy into usable ATP energy.

Chloroplasts

Found only in plant cells; contain chlorophyll that absorbs sunlight and converts it into glucose.

Central Vacuole

Storage facility for water and other materials; some support for the cell.

Cell Wall (Plant)

Made of cellulose; provides support to the plant cell.

Animal Cells

Use a variety of proteins to provide support, strength, and resilience.

Centriole

Found only in animal cells; located outside the nucleus and plays a role in cell division.

Open System (Cell)

Exchange matter and energy with their surroundings and perform intake of nutrients, movement, growth, response to stimuli, exchange of gases, waste removal, and reproduction.

Cell Membrane Role

Separates the intracellular environment from the extracellular environment and selectively allows materials to cross; aka plasma membrane.

Cell Membrane Structure

Double layer, phospholipid bilayer; proteins are suspended in the bilayer.

Fluid Mosaic Model

Membrane proteins are interspersed through the membrane, with their hydrophilic and hydrophobic ends placed accordingly.

Biological Barrier (Cell Membrane)

Prevents many substances from entering cells; surrounds most organelles.

Selective Filter (Cell Membrane)

Semi-permeable – only some particles can move in and out of the cell.

Three Functions of the Cell Membrane

Keeps wastes and toxins out, allows needed substances in; surrounds and packages materials in vesicles; is a selective filter.

Types of Transport Across Cell Membranes

Passive Transport, Active Transport, Endocytosis/Exocytosis

Passive Transport

High concentration to low concentration; no energy (ATP) is required; usually gases (CO2, O2, water) are involved.

Concentration Gradient

Different concentrations of dissolved particles (solutes) exist across a cell membrane.

Brownian Motion

Matter is made up of tiny particles that are in constant motion.

Kinetic Molecular Theory

Space between particles, particles make up all materials, attraction exists between particles, and particles are always moving.

Concentration Gradient

The difference in concentration between the high and low concentration areas.

Diffusion

Molecules always move randomly and from areas of high concentration to areas of low concentration.

Passive Transport - Diffusion

Small molecules move by diffusion (water, oxygen, carbon dioxide).

Osmosis

Water molecules move by diffusion across a membrane.

Hypertonic Solution

Excess of solutes exists in the extracellular fluid; water moves OUT of the cell.

Isotonic Solution

Solute concentrations across the cell membrane are in equilibrium; no net water movement.

Hypotonic Solution

There is a deficit of solutes in the extracellular fluid; water moves IN to the cell.

Honey as a Topical Treatment

Antibacterial, anti-inflammatory, and anti-fungal properties; applied to wounds, creates a hypertonic environment that kills bacteria.

Facilitated Transport (Facilitated Diffusion)

Molecules that are too large to cross the membrane by diffusion (i.e. glucose) use this type of transport.

Active transport

Work against the concentration gradient - low concentration to high concentration - energy (ATP) is required.

Importance of Active Transport

Maintains internal cell environments (i.e. cell’s electrical gradient, roots pull in minerals from soil, filtering blood in your kidneys).

Endocytosis/Exocytosis

Larger particles are involved; the cell membrane is used to create vesicles (endocytosis) or release particles from vesicles (exocytosis).

Phagocytosis

Solids are brought into the cell.

Pinocytosis

Liquids are brought into the cell.

Diffusion and Surface Area

Diffusion over long distances is very slow and inefficient; cells maximize surface area to volume ratio for quick diffusion.

Multicellular Organisms

Multicellular organisms add more cells rather than increase the cell size; cells specialize in many different types.

Levels of Organization

Cells -> Tissues -> Organs -> System -> Organism

Photosynthesis

Carbon dioxide + water -> glucose + oxygen.

Leaf - Cuticle

Waxy coating; protects leaf from water loss.

Leaf - Epidermis

Transparent to allow light to pass through to the underlying layer.

Leaf - Palisade Cells

Main cells for photosynthesis; contain lots of chloroplasts.

Leaf - Vascular Bundle (Vein)

Organizes the two transport tissues into 'highways' throughout the leaf.

Leaf - Xylem

Transports water and minerals from roots to leaves.

Leaf - Phloem

Transports sugar (made in the leaves) to the rest of the plant.

Leaf - Spongy Mesophyll

Loosely packed with many air spaces around them – this tissue helps in water and gas exchange with the environment.

Leaf - Stomata

Openings for gas exchange (CO2 and H2O in, O2 out).

Leaf - Guard Cells

Regulate the size of the stomata (opening) to control H2O loss.

Lenticels

Allow gas flow in the stem and roots of plants.

Plant Vascular System

Extend throughout the plant; made of Xylem and Phloem; transport water, minerals, and sugars throughout the plant.

Xylem

Transports water and dissolved minerals from soil to leaves; cells linked end to end to make long tubes (xylem vessels).

Plant Transport - Water Transport

Root pressure (osmosis), cohesion/adhesion of water in the xylem, and transpiration.

Root Pressure

Water uptake from soil; the soil outside the root is hypotonic to the root cell, so water enters the cell by osmosis.

Cohesion

The attraction of water molecules to other water molecules.

Adhesion

The attraction of water molecules to molecules of other substances (xylem walls).

Transpiration

Evaporation of water through the stomata and lenticels; the 'pull' moving water up into the leaves.

Turgor Pressure

Cell walls that surround the plasma membrane and prevent water from leaving the cell.

Phloem

Transport sugar (sap) from leaves to rest of the plant.

Tropism

Plant growth in response to a stimulus (tropo - turn); can be positive or negative.

Phototropism

The growth response of a plant in response to light direction.

Gravitropism

The growth of a plant in response to gravity.

F. W. Went (1926) and Auxin

Auxin is a hormone – manufactured in 1 area and transported to another location to initiate cell elongation.

Synthetic membranes

Synthetic membranes can be used for the controlled delivery of medication and filtration across membranes

Reverse Osmosis

semi-permeable membrane, contaminates are kept from passing through