Ap bio unit 2 questions

List the differences between a prokaryotic & a eukaryotic cell.

Eukaryotic Cell:

• nucleus (has more DNA) that's bound by a double membrane

• endomembrane organelles in the cytosol (nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, plasma membrane, various types of vesicles & vacuoles)

• typically larger

Prokaryotic Cell:

• no nucleus, but has DNA (circular chromosome) that is concentrated in the nucleoid that's not bound by a membrane

• no endomembrane organelles

• typically smaller

List the similarities between a prokaryotic & a eukaryotic cell.

• plasma membrane

• cytosol (filler)

• chromosomes (carry genes in the form of DNA)

• ribosomes

• phospholipid bilayer

• vacuoles (Plant cells have one large vacuole; animal cells have multiple small vacuoles)

• cytoplasm

• cholesterol

Give two causes for size limits for certain cell types. Which would be considered the main reason for size limits?

The need for a surface area of sufficient area to support the cell's metabolic needs is a major cause of the size limits for certain types of cells.

A large surface area : volume ratio is helpful because nutrients needed to sustain the cell enter via the surface of the cell & are needed in quantities related to the cell volume.

The smaller the size of the object, the larger its surface area : volume ratio.

Ex: In the jelly auger cell lab, diffusion was most efficient in the smallest cube. The larger the cube, the less diffusion occurs because volume increases faster.

• Surface area : volume ratio needs to be small.

• DNA overload - the larger you get, the bigger the result & the more stuff. It cannot handle all the jobs it needs to do.

• As the cell gets bigger = the job of its DNA gets bigger

Function of Rough ER

• Produces proteins for export (protein transport = protein secretion*)

• Active & used in membrane synthesis (synthesizes phospholipids & proteins)

• Aids in synthesis of secretory & other proteins

• Makes membrane, phospholipids, structures

• Protein Production

Function of Smooth ER

• Synthesizes lipids

• Metabolizes carbohydrates

• Detoxifies drugs & poison

• Has a collection of enzymes that detoxify drugs, especially in the LIVER

• Stores calcium ions

• Active in membrane synthesis

Function of Ribosomes

• Make proteins

• Carry out protein synthesis

Function of Golgi Apparatus

• Active in synthesis, modification, sorting, & secretion of cell products

• Tags, sorts, & packages materials into transport vesicles ("UPS headquarters")

Function of Lysosomes

• Breaks down ingested substances, cell macromolecules, food (phagocytosis), & damaged organelles (autotrophy) for recycling

• Gets rid of damaged organelles & waste

• Mainly in Animal Cells

• Active during & help Apoptosis (cell suicide; self-destruct mechanism)

• Turgid (cell membrane is pushing against cell wall & makes the cell stiff)

Function of Vacuole

• The digestion, storage, waste disposal, water balance, plant cell growth & protection.

• Contractile Vacuoles (Animal Cells): pump out excess water in freshwater organisms.

• Food Vacuoles (Animal Cells): fuse with lysosomes (phagocytosis).

• Central Vacuoles (Plant Cells): larger & used for storage of water, & growth.

• "Chaperone"

Function of Mitochondria

• Where cellular respiration occurs

• Where ATP is generated

• In all plant ells

• Powerhouse of the cell

Function of Chloroplast

• Performs photosynthesis

• Converts energy of sunlight to chemical energy stored in sugar molecules

• Contain thylakoids (individual pancakes) that holds the chlorophyll

Function of Cell Membrane

• Encloses the cell

• Selective barrier allowing the passage of oxygen, nutrients, & waste to service the whole cell

• Regulates what enters & leaves the cell (selectively permeable)

Function of Peroxisome

• Contains a collection of enzyme catalysts that breaks down hydrogen peroxide into water & oxygen.

• Digestive enzyme sacs

• Helps detoxify alcohol & other poisons in liver cells

• Break down fatty acids

Function of Cytoskeleton

• Organizes the structures & activities of the cell

• Reinforces the cell's shape & gives mechanical support to the cell

• Interacts with motor proteins to function in cell motility (to move molecules around the cell)

• Provides a track for vesicles & other organelles to travel throughout the cell

• Flexible (can manipulate the plasma/cell membrane so that it bends inward to form food vacuoles)

• Makes up the centrioles in the Animal cell

• Intermediate microfilaments

• Provides structure & helps in movement*

List the all similarities of a nucleus, chloroplasts and mitochondrion.

• Semi-autonomous (can almost live on their own & can grow & divide like a cell)

• Slowly able to function by itself

• Contains their own DNA

• Double-membrane

• Contains ribosomes

• Nuclear division (how we get a new cell)

Explain the process of the Golgi apparatus in modifying proteins and lipids, using transport vesicles, cis and trans sides, cisternae, and secretion vesicles.

(Textbook Pg. 81)

1. Nuclear envelope is connected to rough ER, which is also continuous w/smooth ER.

2. Membranes & proteins produced by the ER flow in the form of transport vesicles to the Golgi.

3. Golgi pinches off transport vesicales & other vesicles that give rise to lysosomes, other types of specialized vesicles, & vacuoles.

4. Lysosome is available for fusion w/another vesicle for digestion.

5. Transport vesicle carries proteins to plasma membrane for secretion.

6. Plasma membrane expands by fusion of vesicles; proteins are secreted from cell.

DNA (Nucleus) >> Rough ER (Ribosomes; form of DNA) >> Golgi Apparatus (cis, cisternae, trans) >> secretion vesicles.

Explain the need for lysosomes and possible results/disease with nonfunctioning lysosomes.

If a lysosome breaks open/leaks its contents, the released enzymes are not very active b/c the cytosol has a neutral pH. The lysomal enzymes dismantle the enclosed material, & the resulting small organic compounds are released to the cytosol for reuse. With the help of lysosomes, the cell continually renews itself.

The cells of people w/inherited lysosomal storage diseases lack a functioning hydrolytic enzyme normally present in lysosomes. The lysosomes become engorged w/indigestible material, which begins to interfere w/other cellular activities.

Ex: Tay-Sachs disease: lipid-digesting enzyme is missing/inactive, & the brain becomes impaired by an accumulation of lipids in the cells.

The lipid grows bigger, & results in nonfunctioning disease in brains cells, which causes the child to digress & die.

Give those organelles which are part of the endomembrane system.

• Nuclear envelope

• Endoplasmic Reticulum (Rough ER & Smooth ER)

• Golgi Apparatus

• Lysosomes

• Plasma Membrane

• Various kinds of vesicles & vacuoles

Why are some organelles part of the endomembrane system?

• Only in eukaryotic cells

• Carries out a variety of tasks in the cell: synthesis of proteins, transport of proteins into membranes & organelles or out of the cell, metabolism & movement of lipids, detoxification of poisons