APBio Unit 4

Magnification

Ratio of objectt size to real size

Resolution

Measure of Image’s Clarity

• Minimum distance 2 points can be separated to be distinguished as 2 separate points

Scanning Electron Microscopy (SEM)

Shows a 3D image of the surface of a specimen

Transmission Electron Microscopy (TEM)

Shows a thin section of a specimen

Cell Fractionation

Breaks up cells in a blender to isolate organelles

• ribosomes are smallest

Prokaryotic Cells Domains

Bacteria & Archaea

Where are prokaryotes DNA concentrated?

Nucleoid

Cell Wall

Rigid structure outside of the plasma membrane

Plasma Membrane

Selective barrier enclosing the cytoplasm to allowpassage of nutrients and waste

Bacterial Chromosome

Circular located in nucleoid

Cytoplasm

Region between nucleus and plasma membrane containing cytosol

Flagella

Locomotion organelles

What makes cells so small?

Surface area to volume ratio.
Every micrometer of surface area allow a limited amount of a particular substance through plasma membrane per second

Microvilli

Long thin projections from cell’s surface that increase surface area

Nuclear Envelope

Double membrane enclosing the nucleus; outer and inner + nuclear lamina

Perforated/pierced by pores, proteins and connected to endoplasmic reticulum

Nuclear Lamina

Net-like array of protein filament that supports nuclear envelope to maintain nucleus shape

What are chromatin made of?

DNA and Histones (protein)

When does chromatin condense enough to see chromosomes

During mitosis

When can nucleoli be seen?

During anything BUT mitosis

Free ribsomes

Suspended in cytosol

Produces proteins that function within the cytosol

Bound ribosomes

Attache to outside of endoplasmic reticulum or nuclear envelope

Produces proteins that are destined for insertation into membrane