BIO 156-Module 5- Cell properties

what is the smallest unit of life

A Cell

what does the unified cell theory state regarding cells?

- all living things are composed of one or more cells. - the cell is the basic unit of life. - New cells arise from existing cells.

what are the structures that are characteristics of a prokaryotic cell?

Like eukaryotic cells, prokaryotic cells are surrounded by a plasma membrane and have DNA, cytoplasm, and ribosomes. Like plant cells, they also have cell walls. Unlike eukaryotic cells, they may have a cell capsule, and they have a single large chromosome that is not surrounded by a nuclear membrane. Prokaryotes may have flagella (also present in some eurkaryotes) for motility, pili for conjugation, and fimbriae for adhesion to surfaces.

How are eukaryotes different than prokaryotes?

Prokaryotes are unicellular smaller than eukaryotes and they lack a nucleus, its DNA is found in the center of the cell called the nucleoid which is NOT membrane bound. Eukaryotic cells can be unicellular or multicellular and they DO have a membrane bound nucleus and membrane bound organelles.

what limits cell size?

cell size is determined by its surface are and volume. the volume of the insides of the cell can only function if the surface area, the size of the outside of the cell, is large enough for things to pass in and out.

describe the role of cells in organims

structure and support, they are the fundamentals of all living things and make up tissues which make up organs etc. they process nutrients, store DNA, provide defense, and they detect and react to external signals.

Explain the relative sizes of different kinds of cells, and how they are visually studied

the small size of prokaryotic cells allows ions and organic molecules that enter them to spread out quickly to other parts of the cell. and the waste of the cell can move out quickly. large eukaryotic cells have evolved to enhance cellular transport and are highly folded such as cells in our intestines

what tissue do fat cells make up? and what does this tissue do?

Fat cells make up a tissue known as adipose, which is referred to as adipocytes. this tissue remove "fat" (ex: fatty acids and glycerol) from the blood stream and store it so that your body has energy available when needed.

what are the 4 common components ALL cells share?

1) A plasma membrane which is an outer covering that separates the cells interior from its surrounding environment.

2) Cytoplasm, a jelly like area where all the components of a cell are found in.

3) DNA, the genetic material of a cell

4) Ribosomes, particles that synthesize proteins

which organelle is not found inside the cytoplasm of the cell?

the Nucleus is not in the cytoplasm of a cell

what is the difference between the smooth and rough ER in terms of both structure and function?

The rough ER has ribosomes, and is thus involved in the production of proteins. The smooth ER does not have ribosomes. It is involved in the synthesis of lipids, carbohydrates, and steroid hormones, the detoxification of medications and poisons, and alcohol metabolism. Smooth ER does not make proteins.

Ribosomes are formed by what structure?

ribosomes are formed by the nucleus.

which organelle is involved in the production of energy in the form of ATP?

the Mitochondrion

Cellular locomotion is performed by what two organelles?

Cilia and Flagella

which organelles modifies, sorts, tags, packages and distributes lipids and proteins?

the Golgi Apparatus is a series of flattened membranous sacs where lipids and proteins gets packaged, tagged and sorted so they wind up in the right place.

In what ways are animal cells structurally different than plant cells?

Animal cells and plant cells have most of the same organelles, except that animal cells have lysosomes and centrioles, whereas plant cells do not, and plant cells have chloroplasts, large central vacuoles, and cell walls, whereas animal cells do not.

what are eukaryotic cells plasma membranes made up of?

a Phospholipid bilayer with embedded proteins that separate internal contents of the cell from its outside environment. A phospholipid is a lipid molecule composed of two fatty acid chains, a glycerol backbone and a phosphate group.

what is the purpose of a plasma membrane?

it regulates the passage of some substances such as organic molecules, ions and water. and preventing the passage of some to maintain internal conditions.

Peroxisomes

peroxisomes are small, round organelles enclosed by single membranes. they carry out chemical reactions that break down fatty acids and amino acids. they also detoxify many poisons that may enter the body.

what's an example of peroxisomes at work?

peroxisomes in liver cells detoxify alcohol.

what are vesicles and vacuoles?

they are membrane bound sacs that function in storage and transport. vacuoles are larger than vesicles and the membrane of a vacuole does not fuse with the membranes of other cellular components. vacuoles function for long term storage.

why do plant cells have a large central vacuole

plant cells have a large central vacuole for water storage.

what is the endomembrane system

the endomembrane system is a group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins.

What organelles are in the endomembrane system?

the nuclear envelope, lysosomes, vesicles, the endoplasmic reticulum, and the Golgi apparatus. and the plasma membrane which technically isn't inside the cell.

Ribosomes

ribosomes are the organelles responsible for protein synthesis.

Mitochondria

the POWERHOUSE OF THE CELL because they are responsible for making ATP which is the cells main energy currency.

explain ATP

every time a cell works, it has to spend ATP so the more work a cell does the more mitochondria it needs to power that work.

what type of cells would have more mitochondria

Muscle cells have lots of mitochondria but a fat cell is much less active so it has fewer.

what does surface area give a cell

more ability to transport

what is cellular respiration?

the formation of ATP from the breakdown of glucose is known as cellular respiration.

what allows water filled plants to stand up straight?

their rigid cell walls

chloroplasts

Like mitochondria, chloroplasts also have their own DNA and ribosomes. Chloroplasts function in photosynthesis and can be found in eukaryotic cells such as plants and algae

endosymbiotic theory

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms

describe the fluid mosaic model of membranes, and what it means to be semi-permeable

The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components—including phospholipids, cholesterol, proteins, and carbohydrates—in which the components are able to flow and change position, while maintaining the basic integrity of the membrane.

passive transport

simple diffusion, facilitated diffusion and osmosis.

passive transport mechanisms do not require energy to occur. substances move DOWN their concentration gradient. like letting a ball fall down a hill it doesn't require the output of energy.

simple diffusion

involves the movement of a substance from an area where it is in high concentration to an area where it is lower in concentration, without the need of a transfer protein.

what molecules use simple diffusion to move in and out of a cell?

small, uncharged molecules like oxygen and carbon dioxide.

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels and transport protein ex: glucose, amino acids and other polar molecules.

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference. from low concentration to high concentration. like pushing a ball up a hill, it requires energy.

how is active transport preformed?

using pumps, like sodium-potassium pump, sodium ions are pumped out of the cell into the extracellular space while potassium ions are pumped into the cell, where they are already high in concentration.

how do proteins help molecules move across cell membranes?

Proteins help molecules move across cell membranes by acting as specialized tunnels and shifting gates that shield polar or charged substances from the hydrophobic (water-fearing) core of the lipid bilayer

Endocytosis

an active transport process where a cell engulfs extracellular material by folding its plasma membrane inward to create a small internal vesicle

Exocytosis

an active transport process where a cell expels large molecules and waste by fusing membrane-bound vesicles with the outer plasma membrane.

Describe the phospholipid bilayer in terms of what parts are polar (hydrophilic) and nonpolar (hydrophobic).

the plasma membrane is made of 2 layers of phospholipid molecules and each phospholipid has one hydrophilic head and two hydrophobic tails. the hydrophobic tails face each other and the hydrophilic layers face out creating a phospholipid bilayer.

What types of molecules can freely pass through the bilayer? What types of molecules need help?

lipid soluble material like vitamins A, D, E, K readily pass through the plasma membranes as well as fat soluble drugs. small molecules like oxygen and carbon dioxide can also get through the membrane easily.

larger polar molecules like sugars and carbohydrates need help from transport proteins.

Which of the mechanisms discussed are passive (down the concentration gradient; no ATP required)? Which are active (up the concentration gradient; ATP is required)?

osmosis, facilitated diffusion and simple diffusion require no ATP.

Define osmosis in terms of hypotonic and hypertonic.

In osmosis, water moves from the hypotonic solution to the hypertonic solution. Note that the water is what is moving, not the solutes, so it still follows the rules of passive transport. There is more water available to move ("free water") in the hypotonic solution, and less in the hypertonic solution.

What moves during osmosis?

only the water, not the solutes

Human blood cells have a solute concentration of about 0.9 percent. Predict what would happen to a blood cell if it was placed in distilled water (distilled water contains, 0 percent, or no solutes). Would the cell gain weight, lose weight, or remain unchanged?

If you draw an arrow from the HYPO solution (the outside, distilled water solution) to the HYPER solution (the solution inside of the cell), it is clear that the arrow is pointing into the cell. The cell will gain water, or gain weight.

What would happen if a blood cell was placed into a fluid with a higher solute concentration than that of the inside of the cell. Suppose you placed the blood cell into a 20 percent salt solution. Would the cell gain weight, lose weight, or remain unchanged?

If you draw an arrow from the HYPO solution (the solution inside of the cell) to the HYPER solution (the outside, 20 percent salt solution), it is clear that the arrow is pointing away from the cell. The cell will lose water, or lose weight.

What would happen to a blood cell if it was placed into a 0.9 percent solute solution? Would the cell gain weight, lose weight, or remain unchanged?

The solution within the cell would be the same as the solution outside of the cell, or in other words, the solutions would be isotonic. No movement of water would occur and the cell would remain unchanged.

In an experiment, a small dialysis bag is filled with a 30% sugar solution. It is placed in a beaker filled with a 55% sugar solution. Assuming that water can pass through the small pores of the dialysis bag, whereas the large sugar molecules cannot, what will happen to the size of the dialysis bag? Why?

If you draw an arrow from the HYPO solution (the 30% sugar solution inside the dialysis bag) to the HYPER solution (the outside, 55% sugar solution), it is clear that the arrow is pointing away from the bag. The bag will lose water, or lose weight.

In an experiment, a small dialysis bag is filled with a 65% sugar solution. It is placed in a beaker filled with a 20% sugar solution. Assuming that water can pass through the small pores of the dialysis bag, whereas the large sugar molecules cannot, what will happen to the size of the dialysis bag? Why?

If you draw an arrow from the HYPO solution (the 20% sugar solution outside of the dialysis bag) to the HYPER solution (the 65% sugar solution in the dialysis bag), it is clear that the arrow is pointing toward from the bag. The bag will gain water, or gain weight.

where direction does water move from in osmosis

FROM the hypotonic solution TO the hypertonic solution.

what happens if a cell gains or loses too much water?

it will either POP and die or shrink and die :(

what does BMI measure?

BMI is a measure of body fat based on a persons height and weight. Gender and age are also considered into the calculation.

who might be incorrectly placed into the category of overweight or obese based on their BMI?

Because muscle weighs more than fat, a person who is very muscular may be incorrectly considered overweight or obese on the BMI scale, even though their body fat is normal

In what areas is body fat most dangerous in terms of increasing the risk of getting various diseases?

Abdominal fat is the riskiest.

what are some health risks associated with being overweight or obese?

various heart problems and disease, hypertension, atherosclerosis (plaque in coronary arteries), stroke, type 2 diabetes, certain cancers, higher levels of bad cholesterol and lower levels of good cholesterol

how are type 1 and type 2 diabetes different? which one used to be mostly associated with adults? which one is related to body fat?

type 1 diabetes involves the loss of insulin as a result of destruction of insulin producing cells in the pancreas. it is not related to body fat. type 2 diabetes involves insulin resistance. it used to be very rare in children, nowadays it is much too common in children.

what are some of the risks associated with anorexia? which are associated with bulimia?

Anorexia risks: osteoporosis (loss in bone density), depression and anxiety, digestive problems, kidney problems due to electrolyte imbalances, and more. Death can occur. Bulimia: irregular heartbeat and heart failure, tooth and gum disease, drug and alcohol abuse, depression and anxiety, dependence on laxatives, kidney failure due to electrolyte imbalances (from dehydration), and more. If left untreated, death can result.