CHAPTER QUESTIONS: UNIT 4

What are the characteristics of passive transport?

- Does not require energy (it is a passive process) typically movement from HIGH to LOW concentration until equilibrium is reached involves smaller sized molecules

These are the factors that restrict the size of a cell:

-Surface area to volume ratio -Nucleo-cytoplasmic ratio -The fragility of the cell membrane -Structures of the cell

what is the metabolic rate of endotherms in comparison to ectotherms ?

5x higher than ectotherms

ways materials go in and out of cells...

Active Transport: Molecules move from area of low concentration to area of high concentration, Energy is required (ATP), Large molecules, ions

how do single - celled organisms maintain homeostasis?

By growing responding to their environment transforming energy reproducing IMPORTANT : Because they consist of just one cell, loss of homeostasis by a single-celled organism would mean the immediate death of the organism. They do no have any other cells that can perform the activities of life for them.

If the environment is ______, ectothermic animals:•Become slow moving and sluggish•Some animals must bask in the Sun (for example snakes or lizards)•Or move to a warmer area (for example some fish) before they can move about to hunt for food.

COLD

If an animal is _________________, they take on the temperature of their surroundings so they don't have to use food energy to keep warm.•This means they don't have to eat as often.

COLD-BLOODED

Endothermic animals must _____ much more often than ectothermic animals since it takes ENERGY to maintain a constant body temperature.

Eat

Describe the two major types of active transport.

Endocytosis is the process of TAKING material INTO the cell by means of pockets throughout the cell. Exocytosis is the process through which many cells RELEASE a large amount of material.

Why does the metabolic waste ammonia pose a problem for all animals?

Even in moderate amounts, ammonia is very poisonous to animals.

How do the differing water balance needs of freshwater animals and saltwater animals explain the difference in their excretion of nitrogenous wastes?

Freshwater animals = more salt than surroundings and LESS water saltwater animals = less salt than surroundings and MORE water.

If the temperature gets too _____, ectothermic animals:•Will need to find a cooler temperature. Or burrow in the ground to keep their bodies cool.

HOT

Ectothermic animals must gain ______ to perform internal activities (for example: digestion can't happen if it isn't warm enough).

Heat

why are most terrestrial animals, including humans, not able to survive by drinking salt water

Human kidneys can only make urine that is less salty than salt water. Therefore, to get rid of all the excess salt taken in by drinking seawater, you have to urinate more water than you drank. Eventually, you die of dehydration even as you become thirstier.

Homeostasis

Maintaining stable internal conditions, like temperature, either internally, or with the help of external environmental factors. Ex: mammals generally stay warm when they have obtained enough energy (food) A lizard stays warm by laying on a rock in the sun, and cools off by hiding in a shady area.

Endothermic = WARM!!!

Means warm-blooded. Body heat regulation comes from INSIDE the animal. Birds and mammals maintain a nearly constant internal temperature THEY do not change with the temperature of the environment.

ways materials go in and out of cells...

Passive Transport: Molecules move from area of high concentration to area of low concentration, No energy needed, Small molecules such as H2O, O2 and CO2

endotherms

People, polar bears, penguins, and prairie dogs, like most other birds and mammals, are endotherms. —are ectotherms.

The key factor that limits the size of a cell is:

Ratio of its surface area to its volume. Small cell size maximizes the ability of diffusion and motor protein to transport nutrients and waste products. Cell size affects the ability of the cell to communicate instructions for cellular functions.

How are transport problems of a freshwater organism difference from those of a saltwater organism?

Salt water: water tends to be removed from cells due to osmosis Fresh water: the opposite! Species that are adapted to those environments have to use ACTIVE TRANSPORT to adjust their water levels to the natural tendencies of osmosis in certain situations.

why are most terrestrial animals, including humans, not able to survive by drinking salt water

Seawater is toxic to humans and most terrestrial animals because your body is unable to get rid of the salt that comes from seawater. Your body normally gets rid of excess salt by having the KIDNEYS produce URINE, but it NEEDS FRESHWATER to DILUTE the SALT in your body for the kidneys to work properly. Normally that is not a problem, as you are always drinking water and eating food with water. Tissue in your body also contains freshwater that can be used. If there is too much salt in your body, your kidneys cannot get enough freshwater to dilute the salt and your body will fail.

Endotherms can survive in a wide range of environments- T or F

TRUE

how do multi- celled organisms maintain homeostasis?

The cells of multicellular organisms perform specialized tasks and communicate with one another in order to maintain homeostasis.

Compare a cell that has grown too large to be efficient with a wireless network that has too many users. Explain how both have the same two problems noted for the city shown in Figure 11.3. Illustrate how "division" helps in both cases.

The larger a cell becomes, the more demands the cell places on its DNA. larger cell == less efficient in moving nutrients and waste materials across cell membrane. Information "Overload" Living cells store critical information in a molecule known as DNA. As a cell grows, that information is used to build the molecules needed for cell growth. But as a cell increases in size, its DNA does not. If a cell were to grow too large, an "information crisis" would occur. To get a better sense of information overload, compare a cell to a growing town. Suppose a small town has a library with a few thousand books. As more people move in, more people will borrow books. Sometimes, people may have to wait to borrow popular books. Similarly, a larger cell would make greater demands on its genetic "library." After a while, the DNA would no longer be able to serve the needs of the growing cell—it might be time to build a new library. Exchanging Materials There is another critical reason why cell size is limited. Food, oxygen, and water enter a cell through its cell membrane. Waste products leave a cell in the same way. The rate at which this exchange takes place depends on the surface area of the cell, which is the total area of its cell membrane. The rate at which food and oxygen are used up and waste products are produced depends on the cell's volume. Understanding the relationship between a cell's surface area and its volume is the key to understanding why cells must divide rather than continue to grow.

Describe how molecules enter and leave a cell without the use of the cell's energy.

Through passive transport molecules move from an area of high concentration of low concentration, this process is diffusion. Flagella and cilia also help with the movement of cells.

Volume of a sphere

V=4/3 π r³

The volume of a sphere increases with the cube of its radius. If the radius of a sphere increases from 2cm to 6cm, by what factor does its volume increase? REALLY KNOW THIS!!!!

Volume Of Sphere= 4/3 * π * r³ Radius Increase From 2cm to 6cm ***first do this 4/3 = 1.3 and π is equal to 3.14 so---multiple those two to get 4.2 NOW---you have your RADIUS in the formula--- They gave us a radius of 2 cm---remember to cube it so 2 cubed is 8 so for first one - radius of 2 cm---we have 4.2 X 8 = 33 ***now ---we already know what this is do this 4/3 x π -------it is 4.2 NOW---you have your next RADIUS in the formula--- They gave us a radius of 6 cm---remember to cube it so 6 cubed is 216 so for first this next one - radius of 6 cm---we have 4.2 X 216 = 907 So, Volume When Radius Is 6/Volume When Radius Is 2 we get - 907 / 33 = 27 That Means Volume Has Increases By 27 Times When Radius Increases From 2cm To 6cm

Describe the process of osmosis?

WATER MOLECULES! molecules from an area of HIGH concentration move to an area area of LOWER concentration. Selectively permeable membrane

Ways endotherms cool off.

When the outside temperature is too hot, the animal can sweat, pant, change position, or change location. Sweating and panting generate heat loss through evaporating water. Changing position and location allow the animal to find a cooler environment in the shade or shelter.

name 2 ways multi- celled organisms maintain homeostasis?

become specialized for a task and cooperate with other cells. communicate with one another.

Ectothermic = COLD **EC = COLD

cold blooded. Body heat depends on OUTSIDE of the animal. Animals, including fish, amphibians, and reptiles, and all invertebrates, have an internal body temperature that changes with the temperature of the environment.

ways materials go in and out of cells...

diffusion (small gases) osmosis (water) facilitated diffusion (ions)

what can animals be classed as depending on how they maintain and control body temperature ?

ectotherms or endotherms

two major types of active transport.

endocytosis exocytosis

ectotherms core body temperatures heavily dependent on what?

environment!!

what animals are ectotherms ?

fish, amphibians, reptiles Iguanas and rattlesnakes

Endotherms generate most of the heat they need ?????

internally.

what do endotherms adaptations allow them to do?

maintain body temperature and to take advantage of warmth from environment

what do endotherms rely upon to warm up ?

metabolic processes

why is endotherms metabolic rate so much higher?

need to consume more food to meet metabolic needs than an ectoderm of the similar size

why do ectotherms on land have a bigger problem with temperature regulation ?

temperature of air can vary dramatically both between seasons and over a 24 hour period from middle of day to end of the night

what do ectotherms living in water not need to do and why ?

thermoregulate , because high heat capacity of water means that the temperature of environment doesn't vary too much

The reason that the cell can grow to a certain limit is its surface area to volume ratio. For example as you air a balloon it expands to a certain volume but there is a limit you can fill air inside the balloon otherwise it will blast. T or F

true

what do endotherms usually maintain?

very stable core body temperature regardless to the temperature of the environment

develop an analogy to explain why specialization and communication are important in your own life (school, dance, violin)

violin----I specialize / concentrate on this instrument alone so I can perfect the tone, notes, technique all my parts need to work together---my brain, fingers, arm, posture, I also have to communicate between my TEACHER and MYSELF----she will give me suggestions or corrections, and I need to make adjustments in order to "survive" or at least improve....

ectotherms they use their surroundings/environment to ???

warm their bodies