Unit 2 Cell biology

All living thing have at least 1 cell

t/f

true
All living thing have at least 1 cell

Cell structure correlated to ____ ____

cell function

______ descend from existing cells

All cells

3 Domains of Life on Earth

ARCHAEA BACTERIA EUKARYA

Prokaryotic cells

No nucleus, no membrane-bounded organelles

Cyanobacteria were on Earth at least

3.5 bya

Cyanobacteria

Photosynthetic

Enabled evolution of oxygen-requiring life forms

Eukaryotic cells at least 2.7 BYA

2.7 BYA

EUKARYOTIC CELLS (DOMAIN Eukarya)

DNA in nucleus

Organelle

Cytoplasm = fluid + organelles

1665 Hooke

coined the word “cell”

Plasma (cell) membrane

selective barrier allows passage of oxygen, nutrients, waste….

what is this

Phospholipid bilayer

what is missing

Hydrophobic tail

Cells have a high surface to

Volume ratio

Larger organisms do have larger cells

t/f

false

Nuclear envelope (NE)

Double membrane; each a bilayer

Pores regulate entry and exit of molecules

Chromatin

is in the nucleus; chromosomes are DNA and associated proteins

Nucleolus

Assembles ribosomes

Ribosomes

Protein Factories

Assemble amino acids into polypeptides

• free ribosomes

• bound ribosomes – bound to NE and ER

what isn’t labeled

mRNA

what is the ?

Codon

what is the ?

large subunit

what is the ?

tRNA

The Endoplasmic Reticulum

• >half of total membrane

• continuous with nuclear envelope

Smooth ER

lacks ribosomes

Rough ER (RER)

has ribosomes

RER

1. Ribosomes assemble amino acids to make a protein

2. New protein enters the ER lumen

3. Protein folds in the ER lumen

The Golgi Apparatus

flattened membranous sacs called cisternae

Golgi has

a cis and a trans face

vesicle with protein from ER Vesicle ____ from the trans Golgi

budding

_____ proteins from ER

Modifies

Functions of the Golgi apparatus

• Modifies proteins from ER

• Add sugars, phosphate, sulfur etc…

• Sorts and packages protein into vesicles PROTEIN

what is happening?

protein synthesis

protein synthesis steps

1. mRNA "reads" the gene and carries the message to the ribosomes either free in the cytoplasm or attached to the endoplasmic reticulum

2. At the ribosomes on the RER, DNA's message gets uncoded and Proteins are produced (with the help of tRNA transfering amino acids (the building units of proteins) to the ribosomes

3. The proteins produced will be transport to the Golgi apparatus which will package the proteins

4. export proteins to the cell or other cells.

Lysosomes

membranous sac of enzymes that digest macromolecules

What do they do?(Lysosomes)

1. get rid of phagocytosed invaders

2. recycle cell parts (autophagy)

3. digest food in single celled organisms

Food vacuole formed via phagocytosis →

lysosome fuses with food vacuole and digests food

Vacuoles

-- Food vacuoles

-- Contractile vacuoles

Contractile vacuoles

• freshwater protists

• pump excess water out of cells

Central vacuoles

•found in many plant cells

• hold starch/water

Mitochondria

cellular respiration generates ATP (energy)

• contain mtDNA

• all eukaryotic cells have mt

• Some have 1, some 1000s

what is gone?

inner membrane

what is gone?

cristae

Plastids

Chloroplasts

Chloroplasts

•plants and algae

•sites of photosynthesis

Cytoskeleton

•Network of protein fibers

•Anchors organelles

•Maintains cell shape

3 proteins of the cytoskeleton

microtubules, microfilaments, intermediate filaments

Cytoskeleton

interacts with motor proteins/kinesins to transport cargo

what is missing

Cargo

missing?

cytoskeletal fiber

Centrioles

Microtubules involved in cell reproduction

Cilia and Flagella

For movement

• Controlled by microtubules

• Found in many protists

Extracellular materials

external to plasma membrane

Plants - cell wall

Composed mainly of cellulose

Composed mainly of ______

cellulose

Animal cells can have a ___ extracellular matrix (ECM)

large

The ECM _____ _____ ____ the cells

anchors and supports

Intercellular Junctions

• Adherence of one cell to another

• Communication through direct physical contact