BM1000 Lecture Notes - Lecture 2: Cell Theory, Cytosol, Lipid Bilayer

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coffeebear832

16 Jul 2018

School

James Cook University

Department

Course

BM1000

Professor

Lionel Hebbard

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Document Summary

Today: evolution through natural selection explains the diversity of modern cells. Light (from the bottom) passes through the specimen. Modern compound microscopes have one lens in the eyepiece and another lens (called the objective) near the specimen. Electron microscopes use a beam of electrons instead of light. Electromagnets help to focus the beam (like lenses in a light microscope) Resolution is about 100,000 times greater than the human eye. Tem: electron beam goes through the very thinly sliced (~ Objects appear darker if they absorb the electrons. Sem: electrons are directed to the surface of the sample, causing other e- to be emitted => Cells are frozen and then cracked open by a knife the electrons. The plasma membrane separates the living cell from its nonliving surround. Membranes separate organelles in eukaryotic cells from the cytoplasm. The membranes of cells are mostly comprised of: lipids and proteins. The lipids (fats) belong to a special category called phospholipids.

Related Questions

Select the statements that correctly represent the theory ofevolution. Select all that apply.

Evolution is partly about inheritance. Evidence of evolution isseen in structures such as wisdom teeth and the tail bone inhumans. These structures are thought to be âleft overâ from ourancestors and no longer appear to have any essential function inmodern humans.

Natural selection means that todayâs organisms are perfectlyadapted after millions of years of fine-tuning. No further changesare necessary because of all the progress that has been made bynatural selection.

We can see evidence of past natural selection in adaptationssuch as the camouflage of moths perched on the bark of their hosttree. We can also see natural selection at work today if we trackhow populations change in rapidly changing environments.

The theory of evolution does not apply to life today. It isstrictly about the history of life: what happened in the past asseen in fossils.

Scientists disagree about the main ideas of evolutionary theorybecause of incomplete or conflicting evidence.

Question 2

Select one answer.

10 points

The ability or tendency of organisms and cells to maintainstable internal conditions is called

metabolism

homeostasis

emergent property

evolution

Question 3

Select one answer.

10 points

Why do organisms maintain fairly steady conditions within theircells and bodies?

They need to keep conditions stable so that they can obtainfood.

Organisms just change along with whatever is happening in theoutside world, which is usually quite steady.

They must maintain stable conditions to keep their enzymesworking and generally to enable the chemical reactions of life.

Unstable conditions will destroy the DNA in cells; this is themost important risk for a cell facing physical or chemicalstress.

Question 4

Select one answer.

10 points

An organism or cell exhibits ____________ when it maintainssteady internal conditions despite changes in the outerenvironment.

homeostasis

evolution

balance

natural selection

Question 5

Select one answer.

10 points

Which type of molecule best illustrates the very strongrelationship between structure and function in biology?

enzymes

oxygen gas

all kinds of organic matter

water

Question 6

Select one answer.

10 points

Which best expresses how nutrients and energy move throughlife?

Nutrients flow from sunlight to organic matter to heat. Energycycles among all life forms.

Nutrients cycle among all life forms. Energy flows from sunlightto chemical energy to heat.

Nutrients and energy both are continually recycled in a greatcircle of life.

Question 7

Select one answer.

10 points

Which of the following is not a recurring theme in biology?

Living organisms maintain homeostasis.

Energy flows through living systems while matter isrecycled.

Evolutionary processes explain both the unity and adaptivediversity of life.

All of these are recurring themes.

Question 8

Select one answer.

10 points

Which statement about evolution is FALSE?

According to evolutionary theory, you are related to abacterium, to a yeast cell, to a snake, and to a whale. In fact,you are related to every species now alive on Earth, and to fossilspecies like dinosaurs as well.

Evolution occurs constantly, without end; there is no endpointin evolution.

Natural selection acts on genetic differences within apopulation to cause evolution. Individuals do not evolve.

Natural selection is about slow but steady progress. Through it,populations constantly get better-adapted. When this process iscompleted for all populations, evolution will come to a stop.

Question 9

Select one answer.

10 points

Imagine you have a peanut butter sandwich in front of you. Thesandwich is an example of _______.

matter

energy

Question 10

Select one answer.

10 points

You provide your gut bacteria with a warm place to live. Theyprovide you with vitamins and other services. This most directlyrepresents an example of...

shared ancestry of all life

natural selection

homeostasis

interdependence of life

It's a quiz for my life science class.

QUESTION 1

Organisms that have descended from the same initial group and have the ability to interbreed belong to the same

	A.	species.
	B.	family.
	C.	class.
	D.	genus.
	E.	order.

5 points

QUESTION 2

The simplest entity that exhibits all of the properties of life is called a(n)

	A.	molecule.
	B.	cell.
	C.	organism.
	D.	tissue.

5 points

QUESTION 3

In populations, adaptation usually arises through

	A.	responsiveness.
	B.	heredity.
	C.	metabolism.
	D.	natural selection.
	E.	development.

5 points

QUESTION 4

Scientists have found that ancient fossils

	A.	are less similar to present-day organisms than more recent fossils.
	B.	are just as similar to present-day organisms as more recent fossils.
	C.	are more similar to present-day organisms than more recent fossils.
	D.	are very similar to present-day organisms.
	E.	bear no resemblance to present-day organisms.

5 points

QUESTION 5

What is the term that describes the study of the relationship between living things and components of their environment?

	A.	herpetology
	B.	analogy
	C.	zoology
	D.	ecology
	E.	ichnology

5 points

QUESTION 6

Characteristics usually associated with life include all of the following except:

	A.	motility.
	B.	a high degree of organization.
	C.	lack of change from generation to generation.
	D.	reproduction.
	E.	responsiveness to stimuli.

5 points

QUESTION 7

The scientific name for the black-footed ferret is Mustela nigripes. The name Mustela indicates the _____________________ to which the organisms belongs.

	A.	phylum
	B.	class
	C.	family
	D.	species
	E.	genus

5 points

QUESTION 8

Which of the following is considered to be the most basic living unit?

	A.	organ system
	B.	molecule
	C.	organelle
	D.	cell
	E.	tissue

5 points

QUESTION 9

Which of the following concepts best describes the wide variety of dog species we observe, ranging from the domesticated golden retriever or the basset hound, to the wild dogs of Africa, to foxes?

	A.	preadaptation
	B.	special creation
	C.	inheritance of acquired characteristics.
	D.	taxonomy
	E.	evolution

5 points

QUESTION 10

If an ecologist is studying the cycling of carbon through a particular environment (which involes the movement of carbon through living things as well as through rock, air, and water), the scientist is studying at what level of ecology?

	A.	organismal
	B.	community
	C.	ecosystem
	D.	population
	E.	biosphere

5 points

QUESTION 11

Which list is organized from smallest to largest level of organization of life?

	A.	organisms, organ systems, organs, tissues, cells, organelles
	B.	organelles, cells, tissues, organs, organ systems, organisms
	C.	organelles, tissues, cells, organ systems, organs, organisms
	D.	tissues, cells, organelles, organs, organ systems, organisms
	E.	cells, tissues, organ systems, organelles, organs, organisms

5 points

QUESTION 12

When examining the hierarchy of life, which of the following terms is most inclusive?

	A.	biosphere
	B.	population
	C.	species
	D.	ecosystem

5 points

QUESTION 13

The units of inheritance are

	A.	evolutions.
	B.	heredities.
	C.	genes
	D.	twins.
	E.	metabolic activities.

5 points

QUESTION 14

Organisms that undergo asexual reproduction

	A.	require another organism to reproduce.
	B.	are usually very complex.
	C.	produce offspring that are different from each other.
	D.	do not require energy to reproduce.
	E.	produce offspring that are identical to each other and to the parent.