AP Bio Chapter 4 Unit 2: Tour of the Cell

Mitochondria is the powerhouse of the cell

Light microscope

A microscope in which visible light is passed through a specimen and then a glass lens, which can effectively magnify the image about 1000x size of the actual specimen

Magnification

Ratio of an object’s image size to its real size

Resolution

The clarity of the image

Contrast

Difference in brightness in the image

Electron microscope

A microscope that uses a beam of electrons to look at an image; 2 kinds; better but more expensive than light microscopes

Scanning electron microscope

The beam of electrons is focused onto the surface of the specimen, resulting in a 3D image

Transmission electron microscope

The beam of electrons is focused through the specimen, resulting in an image depicting the internal structure of the cell; requires a very thin sample

Cell fractionation

The process of breaking up cells and separating their components by using a centrifuge (centrifugation); the heavier the component, the longer the sample needs to spin for (the opposite for lighter components)

Organelles

A sub-cellular structure that has one or more specific jobs to perform in the cell

Eukaryotic cell

A cell that has a nucleus and membrane-bound organelles

Prokaryotic cell

Cells tat do not have a nucleus with the DNA in an unbound region called the nucleoid; no membrane-bound organelles

Basic features of all cells

Chromosomes, ribosomes, cell membrane, cytosol

Cytoplasm

Clear. jelly-like substance that fills the cell along with the organelles in it

Cytosol

Only the liquid part of the cytoplasm

Plasma membrane

Semi-permeable phospholipid bilayer that separates the cell from its outside environment

Nucleus

Organelle that regulates cell functions and contains the cell’s DNA

Nuclear envelope

Double membrane made up of lipid bilayers; separates the nucleus from the cytoplams

Nucleolus

Located within the nucleus and is the site of ribosomal RNA synthesis

Chromosomes

A threadlike, gene-carrying structure found in the nucleus that consists of DNA and proteins condensed together

Chromatin

Makes up chromosomes of eukaryotic cells; consists of DNA, RNA, and proteins

Nucleolus

The site of RNA synthesis; located inside of the nucleus

Ribosomes

Structure made up of proteins and RNA; synthesizes proteins by translating information from mRNA into amino acid strings

Free ribosomes

Synthesizes proteins used in the cytoplasm

Bound ribosomes

Synthesizes proteins that are inserted into membranes, packaged into organelles, or secreted from the cell

Endomembrane system

The system of organelles that work together to modify, package, and transport proteins; components are either continuous or transfer through vesicles

Example: nuclear envelope, ER, Golgi apparatus, lysosomes, vacuoles, plasma membrane

Vesicles

Small membrane-bound sacs that function in moving materials within a cell as well as interactions between cells

Smooth endoplasmic reticulum

Network of membranous tubules and flattened sacs that synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, stores calcium ions; lacks bound ribosomes

Rough endoplasmic reticulum

Network of membranous tubules and flattened sacs studded with bound ribosomes that secrete glycoproteins; distributes transport vesicles and works as a membrane factory for the cell

Glycoproteins

Proteins covalently bonded to carbohydrates

Golgi apparatus

Orgnalle consisting of flattened membranous sacs called cisternae; has a recieving side (cis face) and a shipping side (trans face); modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicles

Lysosome

Membranous sac of hydrolytic enzymes that can digest macromolecules; work best in an internal acidic environment; fuses with the food vacuoles so the enzymes digest the molecules

Autophagy

Process of recycling the cell’s own organelles and macromolecules

Food vacuoles

Large vesicles derived from the ER + Golgi; formed by phagocytosis

Central vacuoles

Found in many mature plant cells, serve as a repository for inorganic ions such as potassium and chloride

Contractile vacuoles

Found in many freshwater protists; pumps out extra water out of cells

Mitochondria

Organelle that generates ATP through cellular respiration; present in nearly all eukaryotic cells; composed of a smooth outer membrane and an inner membrane folded into cristae; inner membrane creates the intermembrane space and the mitochondrial matrix

Cristae

Folded inner membrane of the mitochondria; provides a large surface area for enzymes that synthesize ATP

Chloroplasts

Organelle that generates ATP through photosynthesis; contains chlorophyll + enzymes; found in the cells of leaves + other green organs

Plastids

Double-membrane organelles which are found in the cells of plants and algae; often contain pigments that are used in photosynthesis or to change the color of the cell; responsible for manufacturing and storing food

Endosymbiont theory

The mitochondria and chloroplast in eukaryotic cells were once prokaryotes that were ingested by a larger prokaryotic bacteria and formed a symbiotic relationship which eventually merged into a single organism

Peroxisome

Specialized metabolic compartments bound by a single membrane; detoxify harmful compounds such as alcohol by turning it into hydrogen peroxide and then water