Biology 1.2 Prokaryotic vs Eukaryotic Cells

How to identify palisade cells

- chloroplasts are stringy circle like structures - large vacuole - nucleus is a structure similar to chloroplasts but has smaller holes - small oh

1.2.S1 Identify structures from 2.2.1 in electron micrographs of E. coli.

- may include the following -- cell wall (uniformly thick and drawn outside the plasma membrane) -- capsule (drawn outside the cell wall) -- plasma/cell membrane (drawn as a continuous line) -- ribosome (dark dot) -- nucleoid (irregular shape without nuclear membrane) -- pilli -- plasmid -- SIZE STATED TO BE 1-10 um

1.2.A2 Structure and function of organelles within palisade mesophyll cells of the leaf.

- mesophyll inside the leaf is the site of photosynthesis and includes the palisade cells all the way to the spongy mesophyll cells - palisade cells are rectangular cells under the upper surface of the leaf. Has most chloroplasts - looks like a rectangle under the surface

Bacteria

single-celled organism that lacks a nucleus; prokaryote.

Plasma membrane

Semi-permeable membrane that controls the substances moving into and out of the cell. It contains integral and peripheral proteins. Substances pass through by either active or passive transport.

Mitochondria

The organelle that produces ATP from carbohydrates through aerobic respiration using oxygen

2.3.6 Outline two roles of extracellular components.

The plant cell wall gives the cell a lot of strength and prevents it from bursting under high pressure as it is made up of cellulose arranged in groups called microfibrils. It gives the cell its shape, prevents excessive water up take by osmosis and is the reason why the whole plant can hold itself up against gravity. The animal cell contains glycoproteins in their extracellular matrix which are involved in the support, movement and adhesion of the cell.

ribosomes

They are the site of protein synthesis. Contributes to protein synthesis by translating messenger RNA.

membrane-bound organelles

organelles that are only found within eukaryotic cells. eg. golgi apparatus, nucleus, lysosomes, mitochondria, chloroplasts

1.2.S2 Draw and label a diagram of the ultrastructure of an animal cell.

- cell membrane (continuous line) - nucleus (double membrane and nuclear pores) - mitochondrion (double membrane and nuclear pores) - rough endoplasmic reticulum (drawn to connect nucleus with infoldings and dots to represent bound ribosomes) - golgi apparatus (series of saccs and drawn with evidence of vesicle formation) - free ribosomes (dots) - vesicles and lysosomes (empty ovals)

Draw a labeled diagram of a palisade cell

- cell wall shown with two continuous lines for thickness - plasma membrane shown as single continuous line (can be shown as inner line of the cell wall if clearly labelled) - Nucleus shown with double membrane and nuclear pores - vacuole drawn with single continuous line - chloroplasts shown with double line to indicate envelope and thylakoids - mitochondrion shown with double membrane and cristae

How to identify exocrine gland cells

- mostly made up of Rough ER, Golgi apparatus, and zymogen granules (large black circles) that store and secrete digestive enzymes and used exocytosis - look like a epithelial cell but is more triangular with black dots on the top

Light microscopes

- use lenses to bend light and magnify images - used to study dead or living cells in color - cell movement can be studied

Electron microscopes

- uses electron beams focused by electromagnets to magnify and resolve - requires cells to be killed and chemically treated before viewing so no movement can be seen - without dye no color can be seen

1.2.A1 Structure and function of organelles within exocrine gland cells of the pancreas

-pancreas made up of endocrine and exocrine glands (85% of pancreas) - ACINUS (Acinar cells) synthesize substances for secretion

Outline the steps of binary fission

1. Prepare for division: the parent cell must have enough energy and resources to divide 2. DNA replication: replication is semi conservative and depends on complementary base pairing 3. DNA attachment and cell growth: two DNA molecules attach to a different part of the cell membrane and the cell begins to build more. membrane and wall, elongating the cell 4. Pinching in: cell membrane and wall begin to grow and begin to pinch inwards creating furrows 5. Division: cell membrane and wall continue to grow with two eventually meeting (called a septum) to separate the two 6: Daughter cells: two daughter cells that result are genetically identical to the parent cell

2.3.4 Compare prokaryotic and eukaryotic cells.

1. Prokaryotic cells have naked DNA which is found in the cytoplasm in a region named the nucleoid. On the other hand, eukaryotes have chromosomes that are made up of DNA and protein. These chromosomes are found in the nucleus enclosed in a nuclear envelope. 2. Prokaryotes do not have any mitochondria whereas eukaryotes do. 3. Prokaryotes have small ribosomes (70S) compared to eukaryotes which have large ribosomes (80S). 4. In prokaryotes there are either no or very few organelles bounded by a single membrane in comparison to eukaryotes which have many of them including the Golgi apparatus and the endoplasmic reticulum.

What is the approximate thickness of the plasma membrane of a cell?

10 nm

Cell membrane

A cell structure that controls which substances can enter or leave the cell. Present in all cells.

nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction; in eukaryotes only

Lysosome

An organelle containing digestive enzymes to hydrolyze macromolecules such as proteins and lipids into their monomers

What is a prokaryote

An organism that consists of a single cell that does not have a nucleus.

Chloroplast

Contains chlorophyll and is only present in plant cells; where photosynthesis takes place

Cytoplasm

Contains many enzymes used to catalyze chemical reactions of metabolism and it also contains the DNA in a region called the nucleoid.

1.2.U2 State the meaning and advantages of eukaryotic cells being compartmentalized

Eukaryotic cells have evolved to become efficient spaces where multiple functions can occur at the same time. This means that each region of the cell can be specialized and much more efficient ie. pH is regulated within mitochondria which helps them carry out their function of producing energy; nuclear envelope surrounds DNA so it is less susceptible to mutations

Define extracellular

Extracellular means any structure outside the cell membrane. ie. cell wall, pili, flagellum

Centrosomes

Found in all eukaryotes and necessary for cell division

Pili

Help bacteria adhere to each other for the exchange of genetic material.

1.2.U4 Electron microscopes have a much higher resolution than light microscopes (Electron v Light microscopes)

Light microscopes have a larger field of view, can be magnified up to 2000X, and can resolve objects 200mm apart Electron microscopes have a smaller feild of view, can be magnified up to 250,000 times, can resolve objects that are 0.2 nm apart

Flagella (singular flagellum):

Made of a protein called flagellin. Helps bacteria move around by the use of a motor protein that spins the flagellum like a propeller.

1.2.S3 Interpretations of electron micrographs to identify organelles and deduce the function of specialized cells.

Muscle cells: Have protein filaments that are stacked and overlapped to cause muscle contraction. Contain many mitochondria to provide energy for muscle contraction Nerve cells: have long extensions that connect different parts of the body Red blood cells: flexible disk shape increase surface area and allows O2 and CO2 to diffuse Sperm cells: have acrosome in head with digestive enzymes Skin cells: extremely flattened cells are highly keratinized

Endoplasmic Reticulum (ER)

Network in eukaryotic cells, composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Eukaryotes

Organisms made up of one or more cells that have a nucleus and membrane-bound organelles.

1.2.U1 State differences between plant and animal cells.

Plant cells - have cell walls - have a large central vacuole - store starch (animal cells store glycogen) Animal cells - have centrioles - have cholesterol in the cell membrane - plant cells generally have a fixed shape whereas animal cells are more rounded

What is a function of the plant cell wall?

Prevention of excessive water uptake and provides support

What is the function of the Golgi apparatus?

Processing of proteins for secretion

1.2.U3 State that prokaryotic cells divide by binary fission.

Prokaryotic cells divide by binary fission. Binary fission is a method of asexual reproduction involving the splitting of the parent organism into two separate organisms.

cell wall

Protects the cell from the outside environment and maintains the shape of the cell. It also prevents the cell from bursting if internal pressure rises.

Golgi body

Receives proteins from the rough endoplasmic reticulum and may further modify them. Organelle responsible for packaging and transporting proteins for use outside of the cell.

Nucleoid

Region containing naked DNA which stores the hereditary material (genetic information) that controls the cell and will be passed on to daughter cells.

Define resolution

Resolution is the smallest interval distinguishable by the microscope which then corresponds to the degree of detail visible in an image created by the instrument

Where are proteins synthesized by free ribosomes used?

Within the cytoplasm

State the function of life in Paramecium that is carried out by the contractile vacuole

homeostasis OR maintain osmotic balance / expels «excess» water / maintains «cell» water content

State the function of life in Paramecium that is carried out by cilia

movement/locomotion OR feeding/nutrition

Vacuole

stores materials like water, salts, proteins, and carbs; more common in plant cells