Bio 2000 Chapter 4 Flashcards

Resolution

Ability to observe two adjacent objects as distinct

from one another

Contrast

How different one structure looks from another

Contrast can be enhanced by special dyes to reveal

cellular structure.

Magnification

Ratio between the size of an image produced by a

microscope and its actual size

Light microscope

• Uses light for illumination

• Resolution 0.2 micrometer

Electron microscope

• Uses a beam of electrons for illumination

• Resolution 2 nanometer (100 times better)

What are the three types of light microscopy?

Standard (bright field), Phase Contrast, Differential interference contrast (DIC or Nomarski microscopy)

Types of Electron microscopes

Transmission electron microscopy and Scanning electron microscopy

Standard (bright field) Light Microscopy

Light is focused with glass lenses

Light passes directly through sample

Phase contrast light microscopy

Microscope amplifies differences in phase of light transmitted or

reflected by sample

Improved contrast of denser structures

Differential interference contrast (DIC or

Nomarski light microscopy)

Another method using optics to improve contrast

Good for internal cellular structures

Transmission electron microscopy

(TEM)

Beam of electrons transmitted

through sample

Thin slices stained with heavy metals

Some electrons are scattered while

others pass through to form an

image

Scanning electron microscopy (SEM)

Sample coated with heavy metal

Beam scans surface to make 3D

image

Two primary categories of life

Prokaryotes and Eukaryotes

Prokaryotes

Cell structures without nucleus

Eukaryotes

More complex cells

DNA enclosed within membrane-bound nucleus

Internal membranes form organelles

Two types of Prokaryotic Cells

Bacteria and Archaea

Bacteria

Small cells, 1 micrometer to 10 micrometer in diameter

Very abundant in environment and our bodies

Vast majority are not harmful to humans

Some species cause disease

Archaea

Also small cells, 1 micrometer to 10 micrometer in

diameter

Less common

Often found in extreme environments

What is included inside the typical bacterial cell

Cytoplasm, Nucleoid region, Ribosomes

What is included outside the plasma membrane

Cell wall, Glycocalyx, Appendages

Cytoplasm

contained within plasma membrane

Nucleoid region

where DNA is located

Ribosomes

synthesize proteins

Cell wall

provides support and

protection

Glycocalyx

traps water, gives protection,

help evade immune system

Image of typical bacterial cell

Appendages

pilli (attachment), flagella

(movement)

Eukaryotic Cells Characteristics

DNA is housed inside membrane-

bound nucleus

• Compartmentalized functions

• Organelles

Membrane-bound compartments

Each has a unique structure and

function

• Variety

Shape, size, and organization of cells

vary considerably

Differences between species

Differences between specialized cell

types

Image of animal cell

Image of plant cell

How does a single organism produce different types of cells?

The DNA in different cells is identical — but they have different

proteomes

As cells get larger,

the surface area-to-volume

ratio gets smaller.

What is the Cytosol

Region of an eukaryotic cell that

is outside the cell organelles but

inside the plasma membrane

Cytoplasm includes everything

inside the plasma membrane

Cytosol

Endomembrane system

Semiautonomous organelles

Catabolism

Breakdown of a molecule into smaller components

Anabolism

Synthesis of cellular molecules and macromolecules

Cytoskeleton consists of three types of protein filaments

A network of protein fibers that extend throughout the cytoplasm to provide structure for the eukaryotic cells. Microtubules, Intermediate filaments, and Actin filaments.

Microtubules

Long, hollow cylindrical

structures

Dynamic instability

Intermediate filaments

Intermediate in size

Form twisted, ropelike

structure

Actin filaments

Also known as microfilaments

Long, thin fibers

Motor Proteins

Use ATP as a source of energy for movement

What are the three domains of motor proteins?

The head, hinge and tail

What are the three kinds of movements for motor proteins

• Motor proteins carries cargo along the filament

• Motor protein remains in place, the filament

  moves

• Motor protein and filament both restrained – action of the motor protein exerts a force that bends the filament

Flagella

Usually longer than cilia

Present singly or in pairs

9 + 2 microtubule array

Cilia

Often shorter than flagella

Tend to cover all or part of the cell

surface

Also a 9 + 2 microtubule array

Network of membranes

enclosing the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles

Also includes plasma membrane

Also includes plasma membrane

Image of the nucleus and membrane system

What is included within the nuclear envelope?

Double-membrane structure

enclosing nucleus, Outer membrane of the nuclear

envelope is continuous with the ER

membrane and Nuclear pores provide passageways

Nucleus

• Chromosomes

Composed of DNA and proteins = chromatin

• Nuclear matrix

Filamentous network

Organizes chromosomes

• Ribosome assembly occurs in the nucleolus

Chromatin

Composed of DNA and Proteins

Endoplasmic Reticulum

Network of membranes that form

flattened, fluid-filled tubules or cisternae

ER lumen

Where the ER membrane closes in a single compartment

Rough endoplasmic reticulum (rough ER)

Studded with ribosomes

Involved in protein synthesis and sorting

Smooth endoplasmic reticulum (smooth

ER)

Lacks ribosomes

Detoxification, carbohydrate

metabolism, calcium balance, synthesis,

and modification of lipids

Golgi apparatus

• Stack of flattened, membrane-

bounded compartments

• Vesicles transport materials

between stacks

What are the three overlapping functions of golgi apparatus

Secretion, processing, and protein sorting

Lysosomes

Membrane bound organelles that helps to remove waste in animal cells.Contain acid hydrolases that perform hydrolysis

Autophagy

Recycling of worn-out organelles through endocytosis

Central Vacuoles

in plants for storage and support

Contractile Vacuoles

in protists for expelling excess water

Peroxisomes

Catalyze certain reactions that break down molecules by removing

hydrogen or adding oxygen

What is a byproduct of peroxisomes catalyzing

Hydrogen Peroxide (H2O2)

Catalase

Breaks down dangerous H2O2 into water and oxygen

Plasma membrane

Boundary between the cell

and the extracellular

environment

Functions of Plasma membrane

Membrane transport in and out

of cell, with selective permeability

Cell signaling using receptors

Cell adhesion

Mitochondria and chloroplasts

Grow and divide to reproduce

themselves (endosymbiotic relationship)

• Contain their own DNA, divide by

binary fission

Mitochondria and Chloroplasts are semiautonomous organelles because

They are not completely autonomous

because they depend on the cell for

synthesis of internal components

Mitochondria

• Primary function is to produce ATP

• Also involved in the synthesis, modification, and breakdown of several types of cellular molecules

Photosynthesis

• Capture light energy and use some of that energy to synthesize organic molecules such as glucose.

• Found in nearly all species of plants

  and algae.

Inner mebrane of chloroplast is called

Intermembrane space

Outer membrane of chloroplast is called

Thylakoid membrane

What process do both mitochondria and chloroplast go through?

Endosymbiosis

What kind of endosymbiosis does mitochondria go through?

Modern mitochondria were

derived from purple bacteria,

also called α proteobacteria

What kind of endosymbiosis does chloroplast o through?

Similarly, chloroplasts were

derived from cyanobacteria (a

photosynthetic blue-green

bacteria)

Important table to look at: A Comparison of Cell Complexity Among Bacterial, Animal, and Plant Cells