4.1 -4.3 Studying cells, prokaryotic, and eukaryotic cells

Light vs electron microscopes

Light: Typically involves staining which might kill the cells “normal way to do it”

Electron: Beam of e instead of light, has increased magnification and detail

What are the three tenets of cell theory?

1. All organisms are made of cells

2. Cells are the smallest living things

3. Cells only come from pre-existing cells

Why are cells so small?

As the cell size increases its volume increases much more rapidly than its surface area

• diffusion needs to quickly happens to get nutrients in and waste out

Two adaptations to have cells grow larger

• long skinny cells (neurons) increases SA:V ratio

• Some have many small cells

What do all cells contain?

Plasma membrane, cytoplasm, DNA, and ribosomes

What makes up the plasma membrane of a cell

Glycoprotein (protein with carb attached)

Glycolipid (lipid with carb attached)

Peripheral membrane proteins

Integral membrane proteins

Cholesterol

Protein channels

Phospholipid bilaterally

Filaments of the cytoskeleton

What is a ribosome and why do all cells need them

Uses mRNA and tRNA to produce proteins

Key features of prokaryotic cells

• simple usually single-celled

• Lack a nucleus or other membrane-bound organelles

• DNA found in nucleoid region → in a ring structure

• Many have polysaccharide capsules allow cells to attach to a surface

What is a cell wall comprised of

Peptidoglycan

This is what most antibiotics target

• acts as an extra layer of protection

• helps cells maintain its shape

• prevents dehydration

Key features of eukaryotic cells

• Can be single or multicellular

• Contain a nucleus where DNA is stored in rod-shaped chromosomes

• Contain specialized membrane-bound organelles

Summarize endosymbiosis theory and evidence for it

• Proposes that some of today’s eukaryotic organelles evolved by a symbiosis arising between two cells that were each free-living

• Evidence: Mitochondria and chloroplasts have double membrane (proves it was engulfed), have their own DNA, have their own ribosomes, can copy themselves, divide, and replicate via fission (same size as bacteria)

Where is DNA stored in prokaryotic cells

Nucleotide

What structures do all eukaryotic cells have in common?

• nucleus and nucleolus

• Mitochondria

• Peroxisomes

• Cytoskeleton

• Vacuoles

• Vesicles

Endomembrane system:

• Endoplasmic Reticulum (Rough and smooth)

• Golgi apparatus

Why might some cells have more mitochondria than others what is an example of a cell that would require more mitochondria than others?

Cells requiring high energy for contraction, active transport, or signaling need more power

• muscle cells especially skeletal

Chromosomes and what makes up chromosomes?

Structures within nucleus that are made up of DNA, linear structures 46 in humans

Chromatin makes up chromosomes