Flashcards BIOL 1000 Chapter 4

Cell theory

All living things are composed of cells and all cells come from other cells.

Cellulae

little cells

Light microscopes

Early microscopes, visible light passes through sample and glass lenses (objective/ocular lens), light bent to magnify

How are images from a microscope displayed?

Flipped image

Electron microscopy

Focuses beams of electrons through specimen, electromagnets bend electron path to magnify image, black and white, 100 fold improvement over light microscope.

scanning electron microscope

An electron microscope used to study the fine details of cell surfaces, sample coated with gold, electrons excite the gold, electrons scatter and are detected by screen. 3d image

Transmission electron microscope

electron microscope that is used to study the internal structure of cells. Electron beam through thin section of specimen, stains with heavy metals coat cell structure, electrons scattered by more densely stained parts, scattered electrons detected, image produced.

Small vs big cells

Large cells have less surface area, more volume

Plasma membrane

Flexible boundary between living cell and non-living surroundings, allows things to pass through, phospholipid molecules create its phospholipid bilayer

Prokaryotic cells

Earlier cells, bacteria/archaea, small and simple structure, no internal membrane structure

Eukaryotic cells

Evolved from prokaryotic cells, larger and more complex, membrane enclosed nucleus house DNA, partitioned in functional compartments

What structures do all life have?

Plasma membrane, ribosomes, cytosol, DNA, cytoplasm

Ribosomes

Cell components that use instructions from nucleus to make protein. No membrane. Interact with mRNA to build protein

DNA

One or more chromosomes

Cytosol

Aqueous solution filling cell

Cytoplasm

Entire contents inside cell, excluding interior of the nucleus

Structures only in prokaryotic cells

nucleoid, capsule

Nucleoid

Region of cell where chromosome is, nucleus like

Cell wall (prokaryotic)

Rigid, chemically complex, surrounds plasma membrane, protects and maintains shape

Capsule

Sticky layer on cell wall, glues cells to surface not all prokaryotes have

Flagella

Long projection that propels cells through environment, not all prokaryotes have

Organelle

a membrane-bound structure that performs a specific function in a cell

Functions of organelle

Genetic control of cell, manufacture, distribution and breakdown of molecule, energy processing in plants and animals, structural support/movement and communication between cells

Function of organelle: genetic control

Nucleus and ribosomes

Function of organelle: Manufacture, distribution, breakdown

Endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, peroxisomes

Function of organelle: energy processing

Mitochondria, choloroplasts

Function of organelle: Structural support/movement and communication

Cytoskeleton, plasma membrane, plant cell wall

Cellular metabolism

chemical activities of cells

Animal cells have...

Lysosomes, centrosome, flagella, sometimes cilia

Plant cells have...

cell wall made of cellulose, plasmodesma, chloroplast, large central vacuole, rarely cilia

Plasmodesma

Cytoplasmic channel that links adjacent cells

Chloroplasts

Location of photosynthesis, 2 membranes with thin intermembrane space, contains stroma and thylakoids

Large central vacuole

Stores water and other chemicals

Nucleus

Contains cell DNA, controls cell activities and directs protein synthesis

What do proteins do for DNA

Protein helps coil strands of DNA into chromosomes, human cells have 46 chromosomes

Nuclear envelope

Double membrane enclosing nucleus, regulates the flow of large molecules and connects nucleus to endoplasmic reticulum

Nucleolus

Where rRNA is synthesized. Proteins made in cytoplasm brough to nucleus to assemble rrna make ribosomes

Chromatin

Complex of proteins and DNA

Free ribosomes

suspended in the cytosol

Bound ribosomes

Attached to outside of Endoplasmic reticulum and nucleus. Makes proteins that will be exported from cell

Endomembrane system

regulates protein traffic and performs metabolic functions in the cell. Nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vesicles, vacuoles, plasma membrane

Membrane function

Divides cell into compartments. Either physically connected or linked by transport vesicles

Vesicles

Sac made of membrane

Endoplasmic Reticulum

Network of flattened sacs and tubules, largest part of EM system, linked to nuclear envelope, vesicles bud from it then are transported to other organelles

Smooth Endoplasmic Reticulum

An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down.

Rough Endoplasmic Reticulum

Membranes are rough due to the presence of ribosomes. Proteins are produced from ribosomes often excreted from cells. Grows own membrane and completed membrane transported as vesicles to appropriate area

Golgi apparatus

Stack of unconnected flattened sacs. Warehouse and processing station for molecules produced by ER

Processing in golgi apparatus

1. docking station

2. vesicle adds its membrane and contents to the sac

3. products are modified as they travel from one sac to

the next

4. shipping side

Secretory proteins

these are produced in rough ER and transported to golgi through transport vesicles

Lysosomes

cell organelle filled with enzymes needed to digest food, destroy pathogens, and recycle damaged cell components. Very acidic, protects rest of cell from acidity

Lysosomal diseases

Diseases where lysosomal enzymes are missing and become engorged

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Contractile vacuoles

Spokes collect water, main wheel expels water

Central vacuole

Absorbs water, allows plants to grow, stores vital chemicals and toxic waste products

Peroxisomes

Metabolic membrane bound compartment that does not originate in EM system, breaks down fatty acids for cell fuel, detox of harmful compounds in liver

Mitochondria

Carries out cellular respiration in eukaryotic cells, enclosed by two membranes, both phospholipid bilayers with proteins, inner membrane is highly folded

Mitochondrial matrix

The compartment of the mitochondrion enclosed by the inner membrane, contains DNA, ribosomes, enzymes that catalyze cell respiration

Stroma

Thick fluid in inner membrane of chloroplast, contains DNA, ribosomes, and enzymes

Thylakoids

Network of connected membranous sacs, primary site for photosynthesis

Granum

Stack of thylakoids

Chlorophyll

Embedded in thylakoid membrane to trap solar energy

endosymbiont theory

The theory that mitochondria and chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.

Cytoskeleton

A network of long protein strands (microtubules, intermediate filaments, microfilaments) in the cytosol that helps support the cell. Interacts with motor proteins

Microtubules

Straight hollow tubes composed of tubulins, grows out of centrosome in animals, supports and shapes cell, track where organelles can move, main component of cilia and flagella

Tubulin

Globular protein with two subunits

Centrosome

microtubule organizing center

intermediate filaments

Found in animal cells, threadlike proteins supercoil into cables, reinforces cell shapes and anchors immovable organelles, permanent fixture in cells, outer layer of skin

Microfilaments (actin filaments)

Rods composed of actin proteins, inside cell membrane supports cell shape, involved in cell movements

Actin protein

In microfilaments arranged as a twisted double chain

Why are microfilaments important in animal cells?

They do not have a cell wall so it supports the shape

Cilia

Appendages protruding from cell that move together in a sweeps motion, propel unicellular organisms

Extracellular matrix

Holds together cell in tissue, protects and supports plasma membrane, relays signals that affect gene expression, directs movement of embryonic cells, matrix of glycoproteins outside of plasma membrane (mostly collagen)

Integrins

In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton.

Tight junctions

plasma membranes of adjacent cells tightly knit together, prevents fluid leakage between layers of cells

Anchoring junctions

Intermediate filaments fasten cell together in strong sheets, tissue susceptible to stretching and mechanical stress

Gap junctions

Channels or pores that allow flow of small molecules from one cell to another

Animal cell junctions

anchoring, tight, gap

Cell wall

Found in plant cell, provides cellular support, made of cellulose fibers

Plasmodesmata

channels through cell walls that connect the cytoplasms of adjacent cells and transports nutrients