IB BIO SL 1.2

Eukaryotes are compartmentalized what are some advantages of this?

*Efficiency of Metabolism* -enzymes & substrates can localized and much more concentrated *Localized Conditions* -pH and other factors can be kept at other levels *Toxic/Damaging substances can be Isolated* -digestive enzymes (that could digest itself) stored in lysomes *Number and Location of organelles can be changed* -depending on cell's requirements

Outline the major differences between prokaryotic and eukaryotic cells.

*Prokaryotic Cells* -Smaller (about 0.2 - 2 um) -DNA in nucleoid region (no nuclear membrane)No membrane bound organelles -Cell wall of peptidoglycan -Smaller ribosomes (70s) in cytoplasm -DNA is circular and without histone proteinsHas plasmid DNA -Asexual cell division *Eukaryotic Cells* -Bigger (10-100 um) -DNA in a true nucleus -Membrane bound organelles present -Cell wall of cellulose (plants) or chitin (fungus) -Larger ribosomes (80s) in cytoplasm and on ER//also has 70s ribosomes within mitochondria and chloroplasts// -DNA is linear with histone proteins -Do not have plasmid DNA -Asexual or sexual cell division

Structure of free ribosomes

-80s (eukaryote) -no membrane -appear as dark granules in the cytoplasm -synthesizes proteins in the cytoplasm to function

Outline binary fission, the process in which prokaryotes divide.

-DNA replicated semi-cons. -2 DNA loops attach to membrane -Membrane elongates and pinches off (cytokinesis) -Two daughter cells formed, genetically identical

Light vs. Electron: Resolution

-Human : 100 μm / 100,000 nm- Light : 0.2 μm / 200 nm Electron : 0.001 μm / 1 nm

Structure of mitochondria

-double membrane -smooth outer membrane and inner membrane with foldings -fold are cristae -variable in shape

Structure of chloroplast

-double membrane -stacks of thylakoids (flattened membrane discs) -variable but usually ovoid

Structure of RER

-flattened membrane sacs (cisternae) -located near nucleus -80s are attached to the outside of the cisternae

Ultrastructure of eukaryote

-image

Ultrastructure of prokaryote

-image

Structure of cell wall

-mainly consists of cellulose -permeable //doesn't affect transport in/out of cell -strong //gives support so plasma membrane won't burst -hard to digest //long-lasting as it's resistant to being broken down

Structure of nucleus

-pores in membrane -spherical double membrane -genetic info (DNA and ass. histone proteins) -mRNA is transcribed here, leaves via the pores

Structure of vesicles

-single membrane w/ fluid inside -small in size -transport materials inside the cell

Structure of vacuole

-single membrane w/ fluid inside PLANT -large and permanent -occupying majority of cell volume ANIMAL -small and temporary -used for various reason e.g absorb/digest food

Structure of lysomes

-spherical w/ single membrane -formed from Golgi vesicles -high conc. of enzymes so it stains heavily on microscopes

Structure of flagella

-thin projection from the surface of the cell -contains microtubules

Structure of cilia

-thin projection*s* from the cell's surface -contains microtubles

Structure of centrioles

-two groups of nine microtubules -mainly found in animal cells, not present in plant/fungal

Centrioles

A cell organelle that aids in cell division in animal cells only

Eukaryote

A cell that contains a nucleus and membrane bound organelles

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

/e Which organelle is involved in generating vesicles destined for the cell membrane? A. Golgi apparatus B. Smooth endoplasmic reticulum C. Rough endoplasmic reticulum D. Lysosome

A. Golgi apparatus

/e State on function of mitochondria

ATP production/site of aerobic respiration

/e Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C. Chloroplast D. Mitochondrion

B. Lysome

Lysomes

Breaks down food molecules from the Golgi apparatus with digestive enzymes

/e The following electron micrograph shows part of a palisade mesophyll cell. Which of the labelled structures controls the exchange of substances to and from the cell?

C.

/e An unknown cell is observed using a microscope. A cell wall, ribosomes and DNA are identified. What can be concluded from these observations? A. It can only be a prokaryotic cell. B. It can only be a eukaryotic cell. C. It could be a prokaryotic or eukaryotic cell. D. It can only be a plant cell.

C. It could be a prokaryotic or eukaryotic cell.

/e [images but,,,] Which organelle is involved in vesicle formation A. Mitochondria B. Chloroplast C. Leukocyte D. Nucleus

C. Leukocyte

/e What is the function of the Golgi apparatus? A. Transport of lipids B. Synthesis of polypeptides C. Processing of proteins for secretion D. Generation of most of the cell's supply of ATP

C. Processing of proteins for secretion

/e What is the role of the vesicles shown in the micrograph? A. To transport hormones between the rough endoplasmic reticulum and the Golgi apparatus B. To store glycogen when blood glucose levels are high C. To move enzymes out of the cell by exocytosis D. To digest cellulose

C. To move enzymes out of the cell by exocytosis

Chloroplast (plants only)

Converts sunlight energy into stored energy (sugar) via the process of photosynthesis. (glucose produced)

/e A cell has cytoplasm, a cell wall, naked DNA and ribosomes. Based on this information, what type of cell could this be? A. A cell from a pine tree B. A grasshopper cell C. A human red blood cell D. A bacterium

D. A bacterium

/e Which is a difference between prokaryote and eukaryote cells? D. No ribosomes vs. ribosomes D. No region containing DNA vs. region containing DNA D. No flagella vs. flagella D. No mitochondria vs. mitochondria

D. No mitochondria vs. mitochondria

/e What is a possible explanation for the total percentage resistance being larger than 100% in 2010? A. People do not take the antibiotics as prescribed. B. More people have been sampled in that year. C. There was an epidemic of Neisseria gonorrhoeae in that year. D. Some bacteria are resistant to more than one antibiotic.

D. Some bacteria are resistant to more than one antibiotic.

/e Where are proteins synthesized by free ribosomes used? A. Outside the cell after secretion B. Within the nucleus C. Within the lysosomes D. Within the cytoplasm

D. Within the cytoplasm

Nucleus

It contains DNA; it is the site of replication and transcription.

Light vs. Electron: Resolving

Light: 200 nm (500x better than our eyes) Electron: 0.2 nm (1000x better than light)

Light vs. Electron: Magnification

Light: 2000x (@ school only 400x) Electron: 250,000x (125x than avg. light)

Light vs. Electron: Field of view

Light: Larger Electron: Smaller

Light vs. Electron: Purpose

Light: Study dead or *living* cells in *colour* -cell movement can be studied -see the structure of the cell Electron: Requires cells to be dead and no stain is used -cell movement cannot be studied -see the ultrastructure of the cell

Can electron and light microscopes see viruses?

Light: cannot see viruses Electron: can see viruses

Structure of Golgi apparatus

Like RER has cisternae *BUT* -no attached ribosomes -close to plasma membrane -cisternae are shorter and more curved

/e [2 marks] State three structural difference between the cells of an onion and a honey bee

Onion Cell - cell wall, chloroplasts, large vacuole, fixed shape, starch stored no centrioles/centrosomes Honey Bee - *no* cell wall/chloroplasts/large vacuole/fixed shape - glycogen stored - centrioles/centrosomes

Golgi apparatus

Packages and releases (to vesicle) proteins from RER.

Microtubules

Play a role in cell division and are apart of flagella

Vacuoles

Stores food, water, wastes, and other materials

Cell wall (plants only)

The thick outer layer that surrounds the cell membrane of plant cells (extracellular component not an organelle)

Do chromatids stain dark?

Yes, they stain dark and are concentrated at the edge of the nucleus.

plasmid (prokaryotic)

a small circular piece of DNA carrying genetic information separate from the prokaryotic chromosome

What are ultrastructures ?

all the structures of a biological specimen that are at least 0.1nm in their smallest dimension

80S ribosomes

larger ribosomes found in eukaryotes

Vesicles

membrane sac containing proteins ready for secretion

Electron micrograph on mesophyll cells

mesophyll cells

Cilia (animals only)

move the cell or move fluids that are next to the cell

Smooth Endoplasmic Reticulum (SER)

no ribosomes present

Free ribosomes

site of protein synthesis

Structure of microtubules

small cylindrical fibres

70s ribosomes

smaller ribosomes found in prokaryotes

Rough Endoplasmic Reticulum (RER)

synthesizes and transports proteins (outside by the vesicles to the Golgi apparatus)

Mitochondria (mitochondrion singular)

the organelle that is the site of ATP (energy) production (inner membrane forms cristae)

Resolution

the shortest distance between two points that can be distinguished

Flagella (animals only)

used to move the cell