bio 3

Biofuels

Fuels produced from plant and animal products

Fossil fuels

Fuels produced from the decayed remains of ancient plants and animals; include oil, natural gas, and coal

Photosynthesis

Process by which plants capture energy from the sun and store it in the chemical bonds of sugars

Cellular respiration

The process by which all living organisms extract energy stored in the chemical bonds of molecules and use it for fuel for their life processes

Why are biofuels considered renewable?

The production of biofuels requires only the plant or animal source, sunlight, air, water, and a relatively short amount of time

In t biofuels, fossil fuels, and the food fuels energy from the \_____ is the source of the energy stored in the chemical bonds

sun

What products are released when hydrocarbons are broken down?

-Energy
-CO2
-Water

Energy

The capacity to do work

Work in terms of energy is...

Moving of matter against an opposing force

Kinetic energy

The energy of moving objects

Potential energy

Stored energy; the capacity to do work that results from an object's location, position, or composition

Chemical energy

A type of potential energy in which energy is stored in chemical bonds between atoms or molecules

Thermodynamics

The study of the transformation of energy from one type to another, such as from potential energy to kinetic energy

First law of thermodynamics

A physical law stating that energy cannot be created or destroyed; it can only change from one form to another

Second law of thermodynamics

A physical law stating that every conversion of energy is not perfectly efficient and invariably includes the transformation of some energy into heat

How much energy released from the sun is captured by living organisms?

About 1%

Where does the energy not captured by living organisms from the sun go?

It is reflected back into space (probably about 30%) or is absorbed by land, the oceans, and the atmosphere (about 70%) and mostly transformed into heat

In order to fuel chemical reactions in the cells of organisms the energy first must be captured in the bonds of a molecule called

ATP

Adenosine Triphosphate (ATP)

A molecule that temporarily stores energy for cellular activity in all living organisms. It is composed of adenine, a sugar molecule, and a chain of three negatively charged phosphate groups

Why do the PO4 groups in ATP contain a lot of energy?

They are held together with slightly unstable bonds and the instability of these high-energy bonds means that the three phosphate groups are like a tightly coiled spring. With the slightest push, one of the phosphate groups will pop off. In the process, a little burst of energy will be released that the cell can use

Resulting products from ATP molecule releasing energy are...

ADP (adenosine diphosphate), and a separate phosphate group (labeled Pi)

How can an organism rebuild its ATP stocks?

By using ADP, a free-floating phosphate, and an input of kinetic energy to rebuild them

ATP is considered to be a source of \_______ energy\> When ATP is converted into ADP, \_________ energy is released.

Potential, Kinetic

What other organisms are capable of photosynthesis?

Some bacteria and many other unicellular organisms, along with kelp and other multicellular algae

What does the term "photo" in photosynthesis mean, and what happens?

It means light is captured, what happens is light energy is captured and temporarily saved in energy-storage molecules

What does the term "synthesis" in photosynthesis mean, and what happens?

It means sugar is built, what happens is the energy in the energy-storage molecules is used to assemble sugar molecules from carbon dioxide from the atmosphere

Chloroplasts

The organelle in plant cells in which photosynthesis occurs

Stroma

In the leaf of a green plant, the fluid in the inner compartment of a chloroplast, which contains DNA and protein-making machinery

Thylakoids

Interconnected membranous structures in the stroma of a chloroplast, where light energy is collected and converted to chemical energy in photosynthesis

Photosystems

Two arrangements of light-absorbing pigments, including chlorophyll, within the chloroplast that capture energy from the sun and transform it first into the energy of excited electrons and ultimately into ATP and high-energy electron carriers such as NADPH

Where in the cholorplast is chlorophyll found?

Thylakoid

Light energy

A type of kinetic energy made up of energy packets called photons, which are organized into waves

Photons

The elementary particle that carries the energy of electromagnetic radiation of all wavelengths

Electromagnetic spectrum

The range of wavelengths that produce electromagnetic radiation, extending (in order of decreasing energy) from high-energy, short-wave, gamma rays and X rays, through ultraviolet light, visible light, and infrared light, to very long, low-energy, radio waves

Pigments

In photosynthesis, molecules that are able to absorb the energy of light of specific wavelengths, raising electrons to an excited state in the process

Chlorophyll

A light-absorbing pigment molecule in chloroplasts

Chlorophyll a

The primary photosynthetic pigment. It absorbs blue-violet and red light; because it cannot absorb green light and instead reflects those wavelengths, we perceive the reflected light as the color green

Chlorophyll b

A photosynthetic pigment similar in structure to chlorophyll a. It absorbs blue and red-orange wavelengths and reflects yellow-green wavelengths

Cartoneoids

Pigments that absorb blue-violet and blue-green wavelengths of light and reflect yellow, orange, and red wavelengths of light

The shorter the wavelength, the \____ energy the photon carries

more

Upon absorbing the photon, the electron briefly gains energy, and the \___________ energy in the chlorophyll molecule increases

potential

Two fates of an excited electron:

1) The electron can return to its resting, unexcited state, releasing energy in the process, some of which may bump electrons in a nearby molecule to a higher energy state

2) The excited electron itself can be passed to another molecule

In a chain of electron carrier molecules, would the first or the last electron carrier molecule have a greater affinity for electrons?

First

Why is the passing of electrons a critical first step in photosynthesis?

Process enables a plant to harness light energy from the sun and convert it to usable energy

How can an increase in particles in the atmosphere impact the process of photosynthesis?

They can block sunlight and reduce the excitation of electrons

Light-catching pigments that capture solar energy in the chloroplasts are called \________________________. This harvesting of solar energy occurs in the \________________________ of the chloroplasts.

chlorophyll, thylakoid

Primary electron acceptor

In photosynthesis, a molecule that accepts excited, high-energy electrons from chlorophyll a, beginning the series of electron handoffs known as an electron transport chain

From what molecule does the primary electron acceptor in each photosystem collect its electrons?

Chlorophyll a

Electron transport chain

The path of high-energy electrons moving from one molecule within a membrane to another, coupled to the pumping of protons across the membrane, creating a concentration gradient that is used to make ATP; occurs in mitochondria and chloroplasts

NADPH

Nicotinamide adenine dinucleotide phosphate; a molecule that is a high-energy electron carrier involved in photosynthesis, which stores energy by accepting high-energy protons. It is formed when the electrons released from the splitting of water are passed to NADP+.

The chlorophyll a molecule at the center of the photosystems differs from the other pigment molecules, how?

When its electrons are boosted to an excited state, they do not return to their resting, unexcited state. Instead, a nearby molecule, called the primary electron acceptor, acts like an electron vacuum, grabbing the excited electrons and leaving electron vacancies

The first photosystem produces \_______________ while the second photosystem produces \_________________.

ATP, NADPH

The terminal location of the electrons after they pass through both photosystems is:

NADPH

Calvin Cycle

In photosynthesis, a series of chemical reactions in the stroma of chloroplasts in which sugar molecules are assembled.

Rubisco

An enzyme (ribulose 1,5-bisphosphate carboxylase/oxygenase) involved in photosynthesis. It fixes carbon atoms from CO2 in the air, attaching them to an organic molecule in the stroma of the chloroplast. This fixation is the first step in the Calvin cycle, in which molecules of sugar are assembled. Rubisco is the most abundant protein on earth

The Calvin cycle occurs in the \__________ of the chloroplasts.

Stroma

In order to carry out the Calvin cycle, the items needed from the "photo" reactions are \_______________________and \____________________.

ATP, NADPH

Other than the items needed from the "photo" reactions, what is the additional item needed by plants in order to complete the Calvin cycle?

Carbon Dioxide

Fixation

Using an enzyme called rubisco, plants pluck carbon from the air, where it occurs in the form of carbon dioxide (which has one carbon), and attach, or "fix," it to an organic molecule (which has five carbon atoms) within the chloroplast. Not surprisingly, given its role as the critical chemical that enables plants to build food molecules, rubisco is the most abundant protein on earth.

Sugar creation

The newly built molecule immediately splits in two, and each half is chemically modified. First a phosphate from ATP is added, and then each of the two molecules receives some high-energy electrons from NADPH. The result is two molecules of a three-carbon sugar called glyceraldehyde 3-phosphate (G3P). For the net synthesis of one molecule of G3P from carbon in the atmosphere, three "turns" of the Calvin cycle are required to fix three molecules of carbon dioxide

Regeneration

Not all of the G3P molecules are used to produce sugars. In the third and final phase of the Calvin cycle, some G3P molecules are rearranged to regenerate the original five-carbon molecule. The rearrangement of G3P requires energy from ATP produced in the "photo" reactions of photosynthesis. Once the five-carbon molecule is regenerated, the Calvin cycle can continue to fix carbon and produce molecules of G3P

Not all of the G3P molecules produced in the Calvin cycle are used to make sugar. What sorts of problems would occur if all of the G3P molecules were used to produce sugars for the plant?

The cycle would not continue and would only happen once

What happens to the sugars produced at the end of the "synthesis" reactions?

They are rearranged and regenerated using energy from ATP

Stomata

Small pores, usually on the undersides of leaves, that are the primary sites for gas exchange in plants

C4 photosynthesis

A method (along with C3 and CAM photosynthesis) by which plants fix carbon dioxide, using the carbon to build sugar. It serves as a more effective method than C3 photosynthesis for binding carbon dioxide under low CO2 conditions, such as when plants in warmer climates close their stomata to reduce water loss

CAM

Energetically expensive photosynthesis in which the stomata are open only at night to admit CO2, which is bound to a holding molecule and released to enter the Calvin cycle to make sugar during the day. In this type of photosynthesis, found in many fleshy, juicy plants of hot, dry areas, water loss is reduced because the stomata are closed during the day

What organisms perform cellular respiration?

all living organisms

Glycolysis

In all organisms, the first step in cellular respiration, in which one molecule of glucose is broken into two molecules of pyruvate

Pyruvate

The end product of glycolysis

To generate energy, fuels such as glucose and other carbohydrates, as well as proteins and lipids, are broken down into three steps:

(1) glycolysis, (2) the citric acid cycle, and (3) the electron transport chain

Citric Acid Cycle (Krebs Cycle)

The second step of cellular respiration, in which energy is extracted from sugar molecules as additional molecules of ATP and NADH are formed

While glycolysis occurs in the cytoplasm of cells, the remaining steps occur in the \__________________________ of cells.

mitochondria

Following glycolysis, three modifications to pyruvate must occur prior to the Krebs cycle. They are:

1. As each pyruvate is broken down, a pair of electrons (and a proton) are passed to NAD+, producing NADH

2. A carbon and two oxygen atoms sue released as carbon dioxide.

3. Coenzyme A attaches itself to the remaining molecule, creating acetyl-CoA

After pyruvate is modified, the molecule \______________________ enters the Krebs cycle.

acetyl-coa

Overall, the Krebs cycle involves a lot of rearrangements of molecules that allows for the transfer of high-energy electrons. The molecules that are ready to accept these electrons are called \______________ and \________________. When these molecules actually pick up the electrons they are called \________________ and \________________.

NAD+, FAD, NADH, FADH2

mitochondrial matrix

The space enclosed by the inner mitochondrial membrane, where the carriers NADH and FADH2 begin the electron transport chain by carrying high-energy electrons to molecules embedded in the inner membrane

The electron transport chain serves as the site of the big ATP payoff in cellular respiration. The high-energy electrons needed for this step are delivered by \_______________ and \______________ produced in glycolysis and the Krebs cycle.

NADH and FADH2

Explain the two features of the mitochondrial structure that contribute to its ability to produce energy in the electron transport chain.

1. bag within a bag structure that make s it possible for the regions inside and outside the inner bag to have different concentrations2. inner bag is studded with molecules which are sequentially arranged as a chain

A lack of oxygen has major consequences for how cells perform cellular respiration. When oxygen is in short supply, a certain step of cellular respiration is impeded. That step is the \____________________________.

electron transport chain

Under anaerobic conditions, there are two fermentation pathways cells can potentially use to survive. One of these pathways results in the production of \___________________ while the other pathway produces \__________________.

lactic acid, ethanol

Ethanol

The end product of fermentation of yeast; the alcohol in beer, wine, and spirits

Fermentation

The process by which glycolysis occurs in the absence of oxygen

DNA

A nucleic acid that carries information, in the sequences of its nucleotide bases, about the production of particular proteins.

Nucleotides

A molecule containing a phosphate group, a sugar molecule, and a nitrogen-containing molecule called a base. Nucleotides are the individual units that together, in a unique sequence, constitute a nucleic acid.

Nucleic acid

macromolecule that stores information

Nitrogen-containing bases

Adenine, Guanine, Thymine, Cytosine

Which nitrogen containing bases pair?

Adenine and Thymine, Cytosine and Guanine

Scientists involved in the discovery of DNA

Rosalind Franklin, Maurice Wilkins, James Watson, Francis Crick

What did Rosalind Franklin and Maurice Wilkins do

produced X-ray images of DNA that were critical to decoding its shape

What did James Watson and Francis Crick do

built a model that explained the structure of DNA

Code

In genetics, the base sequence of a gene. Information encoded within the genetic information can be translated into proteins.

Chromosomes

A linear or circular strand of DNA with specific sequences of base pairs. The human genome consists of two copies of each of 23 unique chromosomes, one from the mother and one from the father.

Genome

The full set of DNA present in an individual organism; also can refer to the full set of DNA present in a species.

Gene

The basic unit of heredity; a sequence of DNA nucleotides on a chromosome that carries the information necessary for making a functional product, usually a protein or an RNA molecule.

Locus

The location or position of a gene on a chromosome.

Alleles

Alternative versions of a gene

Trait

Any characteristic or feature of an organism, such as red petal color in a flower.

Introns

A noncoding region of DNA

Exons

The portion of a gene's DNA sequence that codes for amino acids.

Percentage of DNA in humans consisting of genes

about 1%