Elements of Life: The 6 Atoms Important to Biology | AP Biology 1.2

Summary

This video explores the six essential elements for life on Earth: carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur. It delves into the Miller-Urey experiment, demonstrating the formation of life's molecules in Earth's early atmosphere. The video explains carbon's unique ability to form four covalent bonds, central to organic chemistry, and how hydrogen and oxygen's polar nature is vital for life. It also covers hydrocarbons, isomers, and functional groups, highlighting their roles in creating complex biological macromolecules and the biological hierarchy.

Takeaways

• 🌐 The periodic table contains over 100 elements, but life on Earth primarily relies on six: carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur.
• 🔬 The Miller-Urey experiment demonstrated that the early Earth's volatile atmosphere could produce life's molecules without organisms, suggesting a common origin for life.
• 🌿 Carbon is central to life due to its unique ability to form four covalent bonds, which is the basis of organic chemistry.
• 💧 Oxygen and hydrogen are abundant and essential in life, forming water and participating in various biochemical reactions.
• 🔗 Hydrocarbons, composed of carbon and hydrogen, form the backbone of many biological macromolecules and can be modified to have diverse properties.
• 🔄 Isomers, molecules with the same elements but different structures, can have significantly different functions, affecting drug efficacy and biological processes.
• 🔄 Cis-trans isomers and enantiomers are specific types of isomers that can have different biological activities due to their spatial arrangements.
• ⚗️ Functional groups, such as hydroxyl, carbonyl, carboxyl, amino, and phosphate, add specific properties to molecules, enabling complex biochemical reactions.
• 🔬 The study of these elements and their compounds is crucial for understanding the structure and function of cells and organisms, as covered in the AP Biology curriculum.
• 📚 The video serves as a comprehensive guide for students preparing for AP Biology, offering insights into the elements of life and their significance in biological systems.

Q & A

What are the six elements that life on Earth relies heavily on?

Life on Earth relies heavily on carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur.

What is the significance of the Miller Urey experiment in understanding the origins of life?

The Miller Urey experiment demonstrated that the early Earth's atmosphere could create the molecules of life without an actual organism, suggesting that life's building blocks could have formed naturally.

Why is carbon considered the basis of most organic molecules?

Carbon is considered the basis of most organic molecules because it can form four covalent bonds with other molecules, allowing it to create a diverse range of complex structures.

How do the properties of water, which is composed of hydrogen and oxygen, contribute to its importance in living organisms?

Water's polar properties make it an excellent solvent and facilitate many complex reactions in living organisms, such as dehydration and hydration reactions.

What is a hydrocarbon and why are they important in cells?

A hydrocarbon is a chain of carbon and hydrogen atoms. They are important in cells because they form the basis for many biological macromolecules, and by adding different atoms and functional groups, they can take on various properties.

What is an isomer and why are they significant in biology?

An isomer is a molecule with the same elements but a slightly different structure. They are significant because different structural arrangements can lead to drastically different functions in biological systems.

What is the difference between cis and trans isomers?

Cis isomers have functional groups on the same side of a double bond, while trans isomers have functional groups on opposite sides. This difference in spatial arrangement can lead to different biological activities.

What are enantiomers and how can their structure affect their function in organisms?

Enantiomers are molecules that are mirror images of each other. Their structure can affect their function in organisms because they may interact differently with other chiral molecules, potentially leading to different biological effects.

Why are functional groups important in biological molecules?

Functional groups are important because they add specific properties and functions to molecules, enabling them to participate in a wide range of biochemical reactions and processes within living organisms.

How do different functional groups alter the properties of carbon chains in biological molecules?

Different functional groups alter the properties of carbon chains by introducing polarity, acidity, basicity, reactivity, or the ability to form crosslinks, which are essential for the diverse functions of biological molecules.

Outlines

00:00

🌐 The Fundamental Elements of Life

This paragraph introduces the six essential elements for life on Earth: carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur. It discusses the significance of these elements in the context of the AP Biology curriculum, specifically section 1.2, and sets the stage for a deeper exploration of their roles. The Miller-Urey experiment is highlighted as a pivotal historical experiment that demonstrated how life's molecules could originate from simple atmospheric compounds through natural processes like lightning. The paragraph also touches on the concept of biological hierarchy, suggesting a common ancestry for all life due to the shared use of these basic elements. Carbon's unique ability to form four covalent bonds is emphasized, which is fundamental to organic chemistry and the formation of complex organic molecules that are the basis of life.

05:00

💧 The Role of Hydrogen and Oxygen in Life

The second paragraph delves into the importance of hydrogen and oxygen, highlighting their prevalence in water and their roles in biological organisms. It explains how the polar nature of the water molecule, formed by the combination of hydrogen and oxygen, makes it an excellent solvent and a key participant in complex biochemical reactions. The paragraph further discusses hydrocarbons, which are the backbone of many biological macromolecules, and how the addition of different atoms and functional groups can alter their properties. The concept of isomers is introduced, explaining how molecules with the same elements but different structures can have vastly different functions. The paragraph concludes with a quiz for viewers to test their understanding of the material covered.

10:00

🔬 Functional Groups and Their Impact on Biological Molecules

The final paragraph focuses on functional groups, which are essential for adding specific properties to carbon chains in biological molecules. It outlines seven main functional groups: hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, methyl, and phosphate groups, each contributing unique characteristics to molecules. The paragraph explains how these groups enable a wide range of biochemical reactions and interactions, such as the formation of proteins, the creation of rigid 3D structures in proteins, and the provision of energy for cellular processes. The importance of these groups in the formation of DNA and RNA is also mentioned. The video concludes with an invitation for viewers to engage with the content, ask questions, and subscribe for more AP Biology content.

Keywords

💡Miller-Urey experiment

The Miller-Urey experiment was a scientific experiment conducted in 1953 by Stanley Miller and Harold Urey to simulate the early Earth's atmosphere and demonstrate how simple chemical compounds could combine to form more complex molecules essential for life. The experiment showed that, under conditions mimicking early Earth’s atmosphere (water vapor, hydrogen gas, methane, and ammonia), with electrical sparks simulating lightning, organic compounds like urea could form. This supports the idea that life could have arisen from non-living chemicals.

💡Carbon

Carbon is a fundamental element for life, forming the basis of organic molecules due to its ability to form four covalent bonds with other atoms. This unique bonding capacity allows carbon to create long, complex chains and rings essential for macromolecules like proteins, lipids, and nucleic acids. The video emphasizes carbon's role as the 'backbone' of life, crucial for biological diversity and structure.

💡Hydrocarbons

Hydrocarbons are compounds made up entirely of hydrogen and carbon. In the context of biology, hydrocarbons serve as the foundation of many macromolecules. While hydrocarbons themselves are nonpolar and hydrophobic, adding functional groups like oxygen or nitrogen can alter their properties, making them vital in biological processes. The video explains how carbon chains with attached hydrogens form these hydrocarbons, which play a critical role in cell structure.

💡Isomers

Isomers are molecules that contain the same number and types of atoms but are arranged differently, leading to distinct physical and chemical properties. The video describes three types of isomers—structural isomers, cis-trans isomers, and enantiomers—highlighting their importance in biological function. For example, the video explains how the drug ibuprofen’s effectiveness depends on the arrangement of its isomers, with one form being active and the other inactive.

💡Functional groups

Functional groups are specific clusters of atoms attached to carbon chains that confer unique properties and reactivity to organic molecules. The video outlines seven key functional groups in biology, including hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, methyl, and phosphate groups. These groups allow molecules to participate in a wide range of biochemical reactions, influencing everything from protein folding to energy transfer in cells.

💡Phosphate group

Phosphate groups are a key component in biological molecules like ATP and DNA, playing a critical role in energy transfer and the formation of the DNA and RNA backbone. The video mentions that phosphate groups enable molecules to interact with water and release energy, making them essential for cellular functions. Phosphates are particularly important in energy storage and transfer, as seen in molecules like ATP.

💡Dehydration reaction

A dehydration reaction is a type of chemical reaction where water is removed as molecules bond together to form larger, more complex molecules. In biological systems, this process is essential for synthesizing macromolecules such as proteins and carbohydrates. The video references dehydration reactions as part of the process by which complex biological molecules are formed, contrasting it with hydration reactions, which break down these molecules.

💡Cis-trans isomers

Cis-trans isomers are a type of isomer where the positioning of atoms around a double bond differs. In cis isomers, the functional groups are on the same side of the double bond, while in trans isomers, they are on opposite sides. The rigidity of double bonds prevents rotation, giving these isomers different properties. The video explains how this difference in arrangement can affect the function of biological molecules.

💡Enantiomers

Enantiomers are molecules that are mirror images of each other, often around an asymmetric carbon atom. Even though they contain the same atoms, the spatial arrangement leads to distinct biological functions. The video uses the example of lactic acid and the drug ibuprofen to show how enantiomers can have vastly different effects in biological systems, despite being nearly identical in structure.

💡RNA

RNA (ribonucleic acid) is a complex molecule that plays a key role in coding, decoding, regulating, and expressing genes. The video refers to RNA when discussing how complex molecules could have formed on early Earth as a result of chemical reactions in the atmosphere and oceans. This highlights RNA's significance as one of the molecules that may have been central to the origin of life.

Highlights

Life on Earth relies on six key elements: carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur.

The Miller Urey experiment demonstrated the formation of life's molecules from an early Earth-like atmosphere.

Carbon is central to life due to its ability to form four covalent bonds, foundational to organic chemistry.

Oxygen and hydrogen combine to form water, a polar molecule essential for life's solvent and reactions.

Hydrocarbons, composed of carbon and hydrogen, form the basis of many biological macromolecules.

Isomers, molecules with the same elements but different structures, can have drastically different functions.

Cis-trans isomerism arises from the rigidity of double bonds, leading to different molecular configurations.

Enantiomers, mirror-image molecules, can have different biological functions despite identical composition.

Functional groups attached to hydrocarbons give molecules specific properties and roles in biological reactions.

Hydroxyl groups add polarity to molecules, enabling interaction with water and other polar molecules.

Carbonyl groups facilitate a variety of bonds, classifying molecules as aldehydes or ketones.

Carboxyl groups form acids in water, crucial for biochemical reactions and energy transfer.

Amino groups are essential for protein formation, allowing the creation of long chains that fold into functional molecules.

Sulfhydryl groups enable crosslinking in proteins, contributing to their 3D structure and stability.

Methyl groups serve various roles in cells, including gene regulation through DNA methylation.

Phosphate groups allow carbon chains to interact with water and release energy, critical for ATP and nucleic acid backbones.

The video provides a comprehensive overview of the elements and molecular structures fundamental to AP Biology.

Transcripts

[Music]

if you look at the periodic table of

elements

there are over 100 elements that are

known to science

these elements have drastically

different properties based on the number

of protons and electrons they have

however life on earth relies heavily on

only

six of these elements specifically life

on earth requires

carbon oxygen hydrogen nitrogen

phosphorus and sulfur but why these

elements

the ap test will definitely ask this

question in one way or another

so come along with us as we tour the

elements of life

and find out why they are so important

this video covers section 1.2 in the ap

biology curriculum

the elements of life in this video we'll

start by looking at the miller uray

experiment

which helps scientists determine which

elements were most important to life

then we'll examine how carbon forms the

basis of most organic molecules

and why oxygen and hydrogen are also

important

then we'll start to look at how carbon

hydrogen and oxygen

form hydrocarbons and the role

hydrocarbons play in cells

after the quiz we'll see how different

forms of molecules called isomers

can create different functions finally

we'll take a look at how different

functional groups can be added to a

molecule

to allow it to serve different roles in

cells

if you only need to review one of these

topics feel free to skip to the times

outlined here

let's get started in one of the most

famous historical experiments ever

conducted

stanley miller and harold duray were

able to prove

that the highly volatile early

atmosphere of earth

would be able to create the molecules of

life without

an actual organism the team created a

system

in which water vapor was allowed to

react with simple atmospheric compounds

such as hydrogen gas methane and ammonia

while being subjected to powerful

electrical shocks

to stimulate lightning in the early

atmosphere

the scientists found that not only did

these molecules combined in unique ways

but they started to create some of the

same molecules produced by biological

organisms

such as the complex carbon-based

molecule urea

though this experiment was completed in

1953

much more recent research has confirmed

the results

and has shown that even more complex

molecules like rna

could have formed through early natural

reactions

in the earth's atmosphere and oceans

before getting into the complex

macromolecules that organisms need to

survive

we must first understand that there are

several elements that all life is

dependent on

hydrogen carbon nitrogen oxygen

phosphorus and sulfur

while all organisms use these substances

different types of organisms have

different ratios of these atoms in their

body

for example a grasshopper has a ratio of

five

carbon to one nitrogen whereas the grass

it eats

has a ratio of 33 carbon to one nitrogen

this means that the grasshopper's

metabolism incorporates less carbon into

its body

than nitrogen from the food that it eats

this is just one way that organisms can

use the same elements

to create very different structures and

since all organisms on earth use the

same basic elements

it suggests that life on earth has a

common ancestor

think about this though all life on

earth is based on the same set of atoms

organisms combine these atoms into very

different molecules

these molecules then determine the

structure and function of their cells

the structure and function of individual

cells creates organs and organ systems

with different purposes which eventually

creates

organisms that can function very

differently

this is known as the biological

hierarchy and it all starts with the

important atoms we are looking at in

this video

carbon is by far the most important of

the atoms presented earlier

carbon is special because it has the

ability to form

four covalent bonds to other molecules

the study of carbon-based molecules is

known as organic chemistry

carbon has the atomic number six meaning

that it has six

protons and six electrons this means

that carbon stores two electrons in the

inner shell

and four electrons in the outer valence

shell

since the second electron shell of an

atom can hold eight electrons

carbon is constantly trying to fill up

its outer valence shell

by adding four more electrons

this means that carbon naturally forms

four bonds with other atoms

whether that is four separate atoms or

multiple bonds with a single atom

the valence shells of atoms like oxygen

nitrogen or sulfur

do not allow for this many bonds and

therefore do not make the basis of life

on earth

about 71 of the earth's surface is

covered with water

a simple molecule made of one oxygen and

two hydrogen

atoms so it should not be surprising

that hydrogen and oxygen are also

heavily used in living organisms

together oxygen and hydrogen create a

polar molecule

with one side more positive than the

other

this polar property not only makes water

a great solvent

but many molecules utilize this property

to create more complex reactions

for example many large complex

biological macromolecules

are created using dehydration reactions

and the same molecules are broken apart

by hydration reactions

we will cover these reactions in detail

in section 1.3

the basis for almost all biological

macromolecules is long carbon chains

with attached hydrogens

called hydrocarbons hydrocarbons are

naturally nonpolar

and hydrophobic however by adding

different

atoms and functional groups to a carbon

chain it can take on a wide variety of

other properties

for instance by adding oxygen and

hydrogen to a hydrocarbon chain

it becomes a polar molecule

this imbalance of electrons makes the

molecule much easier to combine and

store within cells

this is essentially how complex

molecules like nucleic acids

lipids and many other biological

macromolecules are created

now that we have covered carbon oxygen

and hydrogen

let's see if you can answer a few ap

style questions

you can pause the video now and take

this short quiz

you can find answers to all the

questions in this video through the

quick test prep link in this video's

description

to see how you did

the fact that carbon can form four

distinct bonds with other

atoms also leads to the phenomenon of

isomers

isomers are molecules with the same

elements but a slightly different

structure

structural isomers contain all of the

same atoms

but they are arranged in a slightly

different order these different shapes

can lead to drastically different

functions

cis trans isomers contain double bonds

since double bonds are rigid and cannot

rotate

this leads to different forms of a

molecule based on where the various

functional groups are attached

if the functional groups fall on the

same side of the double bond

the molecule is called the cis isomer if

the functional groups are bonded on

opposite sides of the double bond they

are known as trans-isomers

lastly enantiomers are molecules with

the same atoms

that are arranged like mirror images of

each other around a carbon that forms an

asymmetric center

for example if we flip this mirror image

of d

lactic acid around into the same

orientation

we see that the oh group now projects in

the opposite direction

enantiomers may be either l or d l for

level or

left and d for dextro or right

enantiomers can have vastly different

functions and organisms

based on this relatively minor

structural change

the important thing about isomers is

that they do not always function in

similar ways

consider the drug ibuprofen this is the

active form

it has a methyl group that sits in this

orientation

and a hydrogen atom on the other side of

this asymmetric carbon

in the inactive form the methyl group

changes position

with this hydrogen that tiny change

renders the molecule useless as a

medicine ibuprofen can no longer bind to

the specific receptors throughout the

body

that cause its physiological reactions

isomers are one reason

why it is very difficult to develop

useful medicines

even the best things in life get boring

if you do them for too long

now's a time to take a quick break when

we come back

we'll finish up by looking at the many

different functional groups that give

molecules specific functions

while carbon itself gives rise to the

possibility of isomers

it is also very important what other

molecules are attached to carbon in a

biological molecule

in fact there are several very common

structures that get added to

hydrocarbons that give

molecules different properties they are

called functional groups

namely because they add specific

functions to molecules

and are needed for many complex

biological reactions

there are seven main functional groups

used in biology that add specific

properties to carbon chains

hydroxyl groups add polarity to a

molecule

allowing it to interact with water and

other polar molecules

hydrocarbon chains with a hydroxyl group

at the end are known as

alcohols carbonyl groups

allow a variety of bonds to be formed at

the double bonded oxygen atom

molecules with carbonyl groups are

called aldehydes when the group is at

the end of the molecule

and ketones when it isn't in the middle

carboxyl groups form an acid in water

which allows the molecule to donate a

hydrogen to complete a large variety of

biochemical reactions

similar to how carboxyl groups create an

acid amino groups

act as a base because they are

negatively charged and can attract a

proton

amino groups are crucial for forming

proteins as they allow for the bonds

between two amino acids to form into

long chains

that eventually fold into functional

molecules

sulfhydryl groups can form crosslinks

with other sulfhydryl groups in other

molecules

this is used by many proteins to create

a rigid 3d structure

methyl groups are not reactive but they

serve many roles within a cell

for instance dna methylation makes the

cell

ignore certain genes in the dna code

lastly phosphate groups give carbon

chains the ability to interact with

water

and release energy for other reactions

phosphate groups allow molecules like

atp

to provide energy to many different

reactions that would not be possible

otherwise

phosphate is also a critical atom in the

formation of the dna and rna backbone

that's it for isomers and functional

groups were you following along

you can now pause the video again to

test your knowledge

answers to all the questions in this

video can be found through the quick

test prep link in this video's

description

along with a number of other resources

that can help you study

for ap biology thanks for watching

if you like this video and found it

helpful please like the video

leave us any comments or questions you

have about the elements that are

important to life

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all of our ap biology content good luck