BIO lectures 1-7

Cellular respiration can generate up to

32 molecules of ATP per molecule of glucose

Overall equation for photosynthesis

6CO2 + 6H2O + Light NRG -> C6H12O6 + 6O2

Carotenoids

Chloroplasts also contain a family of yellow-orange pigments absorb mainly blue-green light. It absorb and dissipate excessive light energy that might damage chlorophyll.

Potential energy

stored energy due to the interactions between objects or particles

bioethanol

type of alcohol that is made from wheat, corn, sugar beets, and other food crops and can be used directly as a fuel source in specially designed vehicles or as a gasoline additive.

photosynthesis

used by plants, algae (protists), and certain bacteria to transform light energy into chemical energy. The whole process uses carbon dioxide and water as starting materials, and releases oxygen gas as a by-product. The chemical energy produced via photosynthesis is stored in the bonds of sugar molecules. Organisms that generate their own organic matter from inorganic ingredients are called autotrophs. So the plants and other organisms that do this by photosynthesis are called photoautotrophs and they are the producers for most ecosystems.

history of oxygen on the earth

. Aerobic and anaerobic respiration start with glycolysis, the splitting of glucose to form pyruvic acid. Glycolysis is thus the universal energy-harvesting process of life. The role of glycolysis in both respiration and fermentation has an evolutionary basis. Between 3.5 and 2.7 billion years ago, before significant levels of oxygen were present in Earth's atmosphere, ancient prokaryotes probably used glycolysis to make ATP and generated ATP exclusively from glycolysis. The fact that glycolysis occurs in almost all organisms suggests that it evolved very early in ancestors common to all the domains of life. The location of glycolysis within the cell also implies great antiquity. The pathway does not require any of the membrane-enclosed organelles of the eukaryotic cell, which evolved more than a billion years after the prokaryotic cell. The figure here provides a time line of oxygen and life on the earth.

the citric acid cycle

. Each pyruvic acid loses a carbon as CO2. The remaining fuel molecules, with only two carbons left, are called acetic acid. Electrons are stripped from these molecules and transferred to another molecule of NAD+, forming more NADH. Finally, each acetic acid is attached to a molecule called coenzyme A (CoA) to form acetyl CoA. The CoA escorts the acetic acid into the first reaction of the citric acid cycle and is then stripped and recycled. the citric acid cycle finishes extracting the energy of sugar by dismantling the acetic acid molecules all the way down to CO2. First, acetic acid joins a four-carbon acceptor molecule to form a six-carbon product called citric acid and this is the name from for the series biochemical reaction. For every acetic acid molecule that enters the cycle as fuel, two CO2 molecules eventually exit as a waste product. Along the way, the citric acid cycle harvests energy from the fuel. Some of the energy is used to produce ATP directly. However, the cycle captures much more energy in the form of NADH and another electron carrier called FADH2. All the carbon atoms that entered the cycle as fuel are accounted for as CO2 exhaust, and the four-carbon acceptor molecule is recycled.

chemical energy

A form of potential energy that is stored in chemical bonds between atoms.

chlorophyll

A green pigment found in the chloroplasts of plants, algae, and some bacteria

Passive Transport (Diffusion)

A process that requires no energy to move molecules down their concentration gradient(from high to low concentration)

the struture of ATP

Chemical energy released by the breakdown of organic molecules during cellular respiration is used to generate molecules of ATP. ATP acts like an energy shuttle. It stores energy obtained from food, and releases it later as needed. Such energy transformations are essential for all life on Earth. ATP (adenosine triphosphate) consists of an organic molecule called adenosine plus a tail of three phosphate groups and is broken down to ADP, adenosine diphosphate, and a phosphate group, releasing energy. The release of the phosphate at the tip of the triphosphate tail makes energy available to cells.

electron transport

During cellular respiration, the electrons gathered from food molecules "fall" in a stepwise cascade down an energy staircase and unlock chemical energy in small amounts, bit by bit. The electrons from organic fuel which is food to NAD+ and converts it to NADH. The rest of the staircase consists of an electron transport chain reactions. Finally, Hydrogens, electrons and oxygen combine to form water. So oxygen plays a very important role in the cellular respiration.

The equation of photon energy E is

E= hc/λ

The third stage of cellular respiration is electron transport.

Electrons captured from food by NADH are stripped of their energy until they are finally combined with oxygen to form water. Electron transport from NADH to oxygen releases the energy your cells use to make most of their ATP.

conservation of energy

Energy cannot be created or destroyed

what is energy?

Energy is defined as the capacity to cause change.

kinetic energy

Energy of motion/movement.

Photosynthesis occurs in two stage

First stage is called light reactions. In the light reactions, chlorophyll in the thylakoid membranes absorbs solar energy, which is then converted to the chemical energy of ATP and NADPH. Meanwhile, water is split to provide a source of electrons and give off oxygen gas as a by-product. Then the photosynthesis goes to the next stage called Calvin cycle. The Calvin cycle uses the products of the light reactions to make sugar from carbon dioxide. ATP generated by the light reactions provides the energy for sugar synthesis. The NADPH produced by the light reactions provides the high-energy electrons that drive the synthesis of glucose from carbon dioxide. Thus, the Calvin cycle indirectly depends on light to produce sugar because it requires the supply of ATP and NADPH produced by the light reactions. The initial incorporation of carbon from the atmosphere into organic compounds is called carbon fixation. This can help reduce the concentration of carbon dioxide in the atmosphere. That's why nowadays we are advocating to keep forest and plant more trees to reduce the carbon produced by our human beings.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Theodor Engelmann hypothesis

Oxygen- seeking bacteria will congregate near regions of algae performing the most photosynthesis. He designed an experiment as the figure shows. In this experiment, he laid a string of freshwater algal cells in a drop of water on a microscope slide. He also added oxygen-sensitive bacteria to the drop and used a prism to create a spectrum of light shining on the slide. The results turned that most bacteria congregated around algae exposed to red-orange and blue-violet light, and very few moved to middle areas of green light.

the energy flow and chemical cycling in ecosystems

The chemical ingredients for photosynthesis are carbon dioxide (CO2) and water (H2O). CO2 passes from the air into a plant via tiny pores. H2O is absorbed from the soil by the plant's roots. Inside leaf cells, tiny structures called chloroplast use light energy to rearrange the atoms of these ingredients to produce most importantly sugar glucose (C6H12O6) and other organic molecules.

Fermentation alone is enough to sustain many microorganisms

The lactic acid produced by yeast using lactic acid fermentation is used to produce cheese, sour cream, and yogurt, soy sauce, pickles, cabbage, and olives, and sausage meat products. So without the fermentation, you may not experience so many tasty food. Yeast is capable of cellular respiration and fermentation. It can perform alcoholic fermentation to produce CO2 and ethyl alcohol instead of lactic acid.

There are two photosystems cooperating in the light reactions:

The main key points you need to remember her are that the light reactions are located in the thylakoid membrane, and the two photosystems and the electron transport chain that connects them transfer electrons from H2O to NADP+, producing NADPH.

ATP energizes other molecules in cells by transferring phosphate groups to those molecules... what does this energy do?

This energy helps cells change shape, enables the transport of ions and other dissolved substances across the membranes, and drives the production of a cell's large molecules.

aerobic metabolism

When there is enough oxygen reaching your cells to support their energy needs

glycolysis which is the first stage

a molecule of glucose is split into two molecules of a compound called pyruvic acid which are usually located in the cytoplasm. Next, the citric acid cycle (also called the Krebs cycle) uses enzymes that are dissolved in the fluid within mitochondria and completes the breakdown of glucose all the way to CO2, which is then released as a waste product.

glycolysis

a six-carbon glucose molecule is split in half to form two 3-carbon molecules by using 2 ATP molecules. Then each three-carbon molecule donates high-energy electrons to NAD+ to form NADH. When enzymes transfer phosphate groups from fuel molecules to ADP, each three- carbon molecule can produce 2 ATP molecules so the total ATP production for the electron transfer is 4 ATP molecule. Considering the earlier consumption of break down 2 ATP molecules, the glycolysis of one glucose thus produce a net of two ATP molecules.

The Calvin cycle functions like

a sugar factory within a chloroplast and regenerates the starting material with each turn. With each turn of the cycle, there are chemical inputs and outputs. The inputs are CO2 from the air, ATP and NADPH produced by the light reactions. The Calvin cycle constructs an energy-rich sugar molecule called glyceraldehyde 3-phosphate (G3P) using carbon from CO2, energy from ATP, and high-energy electrons from NADPH. The plant cell can then use G3P as the raw material to make glucose and other organic compounds.

Chloroplast

are light-absorbing organelles and it is the site of photosynthesis. Chloroplasts are found mostly in the interior cells of leaves. Their green color is from chlorophyll which is a pigment in the chloroplasts that plays a central role in converting solar energy to chemical energ

"self-feeders"

are organisms that make all their own organic matter, including carbohydrates, lipids, proteins, and nucleic acids, from nutrients that are entirely inorganic which are carbon dioxide from the air, water and minerals from the soil

Beta-carotene

bright orange or red pigment found in pumpkins, sweet potatoes, and carrots

Lycopene

bright red pigment found in tomatoes, watermelon, and red peppers and it is an antioxidant that is being studied for potential anti-cancer properties.

biofuels

energy obtained from living materials

Stroma

fluid portion of the chloroplast; outside of the thylakoids

Muscle cells have to obtain this energy (For many endurance athletes, the rate at which oxygen is provided to working muscles is the limiting factor in their performance. When your muscles need a continuous supply of energy to perform work.)

from the sugar glucose through a series of chemical reactions that depend upon a constant input of oxygen (O2).

The many chemical reactions that make up cellular respiration can be grouped into three main stages

glycolysis, the citric acid cycle, and electron transport

sunlight

is a type of energy called radiation, or electromagnetic energy.

Cellular respiration

is aerobic harvesting of chemical energy from organic fuel molecules. This is the main way that chemical energy is harvested from food and converted to ATP, and an aerobic process which requires oxygen.

calorie

is defined as the energy required to raise the temperature of 1 gram (g) of water by 1°C.

Fermentation

is the anaerobic (without oxygen) harvest of food energy. After functioning anaerobically for about 15 seconds, muscle cells begin to generate ATP by the process of fermentation. Fermentation relies on glycolysis to produce ATP. T

aerobic capacity

is the maximum rate at which O2 can be taken in and used by your muscle cells and hence the most strenuous exercise that your body can maintain aerobically.

Metabolism

is the total of all chemical reactions in an organism

. The main function of cellular respiration

is to generate ATP for cellular work. The process can produce around 32 ATP molecules for each glucose molecule consumed. Most often, the fuel molecule used by cells is glucose which is a simple sugar (monosaccharide) with the formula C6H12O6. Cellular respiration consists of many chemical steps, with more than two dozen reactions in all. It also involves specific enzymes to catalyze each reaction. Cellular respiration constitutes one of the most important metabolic pathways for nearly every eukaryotic cell, and provides the energy these cells need to maintain the functions of life. This equation summarizes the transformation of 1 glucose during cellular respiration.

A by-product of photosynthesis

oxygen gas (O2). Both animals and plants use the organic products of photosynthesis as sources of energy. A chemical process called cellular respiration harvests energy that is stored in sugars and other organic molecules. Cellular respiration uses O2 to help convert the energy stored in the chemical bonds of organic fuels to another source of chemical energy called ATP. Cells expend ATP for almost all their work. In plants and animals, the production of ATP during cellular respiration occurs mainly in organelles called mitochondria. The waste products of cellular respiration are CO2 and H2O, the very same ingredients used for photosynthesis. Plants store chemical energy via photosynthesis and then harvest this energy via cellular respiration. Plants usually make more organic molecules than they need for fuel. This photosynthetic surplus provides material for the plant to grow or can be stored, as starch in potatoes which can be human's food.

autotrophs as... heterotrophs as...

producers consumers

anaerobic metabolism

the demand for oxygen in your muscles will outstrip your body's ability to deliver it, and your muscle cells will switch to an "emergency mode" in which they break down glucose very inefficiently and produce lactic acid as a by-product. Every living organism depends on processes that provide energy and cells harvest food energy and put it to work with the help of oxygen.

Stromata

the small openings on the undersides of most leaves through which oxygen and carbon dioxide can move

Heterotrophs

which are other-feeders include humans and other animals and they cannot make organic molecules from inorganic ones.