BIO 101 Exam 1: Chapter 3 (A tour of the cell)

What would lead to hyperglycemia?

1) A loss of insulin receptors 2) Destruction of insulin producing pancreas cells

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

Why are you able to fast for many hours without become hypoglycemic? What controls are in place in your body?

-

Structure of a chloroplast

- 2 phospholipid bi-layers (inner and outer membrane) - Stoma: A thick fluid inside the inner membrane - Thylakoids: Network of interconnected sacs in the stroma - Granum: Stack of thylakoids

Structure of a mitochondria

- 2 phospholipid bi-layers (inner and outter membrane) - Mitochondrial Matrix: A compartment within the inner membrane - Cristae: Folds on the inner membrane - Intermembrane Space: Narrow region between the outer and inner membranes

endomembrane system

- Cells network of internal membranes - ER - Golgi - Lysosomes - Nuclear envelope

Eukaryotic Cell

- Eukaryotic cells are distinguished by having a membrane- enclosed nucleus, which houses most of their DNA, and many membrane-enclosed organelles that perform specific functions.

Difference between an animal and a plant cell

- Found in animal cells but not plant cells: lysosomes and centrosomes - Plant cell has that an animal cell does not: Rigid, thick cell wall (which contains the polysaccharide cellulose), plasmodesmata (cytoplasmic channels through cell walls that connect adjacent cells), chloroplast (location of photosynthesis), and a large central vacuole (a compartment that stores water and a variety of chemicals)

Type II diabetics have enough insulin (at least earlier in the disease). How could they have high blood sugar if they have enough insulin? What else could be "broken"?

- Insulin resistant cell + defective signaling of insulin receptors

What is a lysosome? What is the function of lysosomes?

- Lysosome: A membrane enclosed sac of digestive enzymes - "Breakdown body" - They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. Lysosomes are like the stomach of the cell

What is the function of mitochondria?

- Mitochondria carry out cellular respiration in nearly all Eukaryotic cells. - Mitochondria use 02 and release CO2 in transforming the chemical energy of foods to form ATP that can be used for cellular work

What would make the best antibiotic target? -Mitochondria? -Cell membranes? -Ribosomes? -Cell wall? -DNA?

- Multiple answers - Some antibiotics work to break down the structure of the bacterium: destroy the cell wall - Other antibiotics work to destroy information pathways: a.interfere with the bacteria cell's ability to replicate its DNA (can't divide/reproduce without this). b.interfere with the cell's ability to make proteins at the ribosomes.

What barrier separates the cell's genetic information from the cell's cytosol?

- Nuclear envelope

Difference between prokaryotes and eukaryotes

- Prokaryotes are smaller and simpler in structure - No membrane surronds DNA in prokaryotes - Ribosomes differ slightly in prokaryotes - Prokaryotes do not have a nucleus or other membrane-enclosed organelles

How do materials enter and exit the nucleus ?

- Protein-lined pores

The rough ER and Golgi form a functional unit that help to do what for the cell?

- Secrete proteins out of your cells - The Golgi receives transport vesicles budded from the ER that contain proteins synthesized by bound ribosomes - One side of the Golgi stack serves as a receiving dock for transport vesicles produced by the ER - Products of the ER are modified as they progress through the stack - The Golgi finishes processing the proteins and dispatches transport vesicles to the plasma membrane, where the proteins are secreted - Various Golgi enzymes modify the carbohydrate portions of the glycoproteins, removing some sugars and substituting others

What is one disease associated with malfunction of the lysosomal enzymes?

- Tay sachs disease

What is the advantage for the cell in having "compartments" within a eukaryotic cell?

- The organelles perform specific tasks. - The organelles partition the cell into functional compartments in which many of its chemical activities take place - Also, because the cell's compartments provide different local environments that facilitate specific metabolic functions, incompatible processes can go on simultaneously inside the same cell.

Prokaryotic cells

- Type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles: found only in the domains of bacteria and archaea

How does the CTFR modulator Orkambi treat CF?

1. . Enable defective CFTR to be exported to the membrane 2. Increase the activity of the protein once it is there, supporting the flow of salt and fluids

What is the cause of cystic fibrosis?

: Lung cells produce CFTR but it cannot be successfully exported from the cell, thus there is no CFTR on the plasma membrane of lung cells.

Put these in size order: bacterium, human liver cell, ribosome, insulin (a protein), human egg, a carbon atom.

Carbon atom, insulin, Ribosome, Bacterium, Human liver cell, human egg

Why can't cells get very big?

Cells are so little, so they can maximize their ratio of surface area to volume. Smaller cells have a higher ratio which allow more molecules and ions move across the cell membrane per unit of cytoplasmic volume. Cells are so small because they need to be able to get the nutrients in and the waste out quickly.

What is the function of chloroplasts?

Chloroplasts are the photosynthesizing organelles of plants and algae

What is the function of a cytoskeleton?

Cytoskeleton is the network of protein fibers that extend throughout a cell for structural support as well as movement

All eukaryotes have mitochondria, but not all eukaryotes have chloroplasts. Can you propose an evolutionary explanation for this observation?

Endosymbiotic theory: - Mitochondria and chloroplasts were once primitive bacterial cells - Theory describes how a large host cell and ingested bacteria could easily become dependent on one another for survival, resulting in a permanent relationship -Over millions of years of evolution, all cells began to have mitochondria because it was needed for the production of ATP -Only those cells that needed it began to have chloroplasts

What is the difference between proteins that are made on either free ribosomes in the cytosol or Ribosomes attached to the ER or Nuclear envelope?

Free Ribosomes in the cytosol: Proteins function within the cytosol (e.g. enzymes that catalyze the first steps of sugar breakdown for cellular respiration.) Ribosomes attached to the ER or nuclear envelope: Proteins will be exported from the cell

What might happen if a person injected themselves with too much insulin? What might be the consequence?

Hypoglycemia

What is the function on insulin?

Insulin functions a bit like a key to a door. Without insulin the glucose transporters proteins will not make it to the surface of the cell and glucose will not enter a cell.

Insulin secretion

Insulin secretion in beta cells is triggered by rising blood glucose levels. Starting with the uptake of glucose by the GLUT2 transporter, the glycolytic phosphorylation of glucose causes a rise in the ATP:ADP ratio. This rise inactivates the potassium channel that depolarizes the membrane, causing the calcium channel to open up allowing calcium ions to flow inward. The ensuing rise in levels of calcium leads to the exocytotic release of insulin from their storage granule.

What are the three fibers that make up the cytoskeleton?

Microtubules (shape and support the cell and also act as tracks along which organelles equipped with motor proteins move) Intermediate Filaments: (reinforce cell shape and anchor some organelles) Microfilaments (reinforce cell shape and anchor some organelles)

Similarities between prokaryotes and eukaryotes

Plasma membrane, cytosol, chromosomes (which carry genes made of DNA), ribosomes (make proteins according to instructions from genes), and cytoplasm

Exocytosis

Process by which a cell releases large amounts of material

____________ cause diseases and antibiotics specifically target them List some types of those diseases:

Prokaryotes - Skin infections Food poisoning Ulcers Diarrhea Tuberculosis Ear infections Gum disease Pneumonia Urinary tract infection

DNA holds the instructions for making _________ ?

Proteins

What makes lipids?

Smooth ER

CTFR protein

The CFTR (Cystic fibrosis transmembrane conductance regulator) protein normally functions in various cells attached to the plasma membrane, allowing chloride ion transport.

A cell with many ribosomes tells you what about the cell's function?

The cell produces a lot of proteins

DNA How do materials enter and exit the nucleus?

The cell's genetic instructions inside the nucleus - Protein-lined pores

What is the structure and function of the plasma membrane?

The primary function of the plasma membrane is to regulate the flow of material into and out of the cell. - It is composed of phospholipids that form a layer called the phospholipid bilayer - The phospholipids' hydrophilic heads face outwards, exposed to the aqueous solutions on both sides of the membrane - The hydrophobic tails point inward, shielded from water. Proteins are also imbedded.

As cell size increases, what happens to its surface-to-volume ratio?

The surface-to-volume ratio gets smaller - When a cell grows, its volume increases at a greater rate than its surface area, therefore it's SA/V ratio decreases.

Why do type 1 diabetic have no insulin?

They don't have the beta pancreatic cells that produce insulin (Autoimmune reaction- their body destroys these cells).

What would happen to the system without insulin?

Without insulin the glucose stays in the blood and circulates while the cell starves for nutrition.

How is mRNA made?

by copying the code from DNA

Purpose of mRNA

act as an intermediary between the genetic information in DNA and the amino acid sequence of proteins

What does the Golgi apparatus do?

directs proteins (rough ER) and lipids (smooth ER) produced by the ER to their final destination, transported by vesicles

Muscle and liver cells that take up more glucose then they need can store it as ________ inside cells

glycogen!

What is hyperglycemia? symptoms?

high blood sugar - unquenchable thirst, frequent urination, blurry vision, weight loss etc.

What is hypoglycemia? Symptoms?

low blood sugar - shaking, sweating, fainting, seizure, coma

What carries genetic instructions for making proteins from the nucleus into the cytoplasm?

mRNA "The messenger)

Alpha cells

secrete glucagon

beta cells

secrete insulin

Two types of ER:

smooth and rough ER Rough ER has ribosomes attached to it