Bio Exam 2 Chap 4-6

Nutrients

chemical building blocks our bodies need to live, grow, and repair themselves, provide energy. Energy source for heterotrophs. Broken down into macro (Carbs, fats, protein) and micronutrients (nucleic acids, vitamins, minerals).

Energy

ability to do work, powers our activities, helps build complex muscles. Can be kenetic or potential

macronutrients

nutrients that organisms must ingest in large amounts to maintain health. Ex: carbohydrates, proteins, lipids (fats). Many foods contain all 3 types, proportion of each varies. Animal products contain more protein per gram than carbs, opposite for most plant products

a varied diet must include____

vegetables, oils, grains, meat, dairy products

digestion

process of breaking down huge food molecules (macronutrients) into smaller pieces so that our bodies can use them, series of chemical reactions to break the bonds that hold food molecules together, starts in the mouth and continues throughout the digestive system

Carbohydrates

broken down into simple sugars, used to build cell-surface markers, energy-storage molecules (glycogen)

Proteins

broken down into amino acids, used to assemble new proteins that have many different functions in the body. essential nutrient (9/20 amino acids can only come from diet)

Fats (Lipids)

broken down into fatty acids and glycerol, used to build molecules that form cell membranes

Nucleic acids are NOT macronutrients

are provided in smaller amounts, broken down into individual nucleotides, used to build DNA and RNA

Essential Nutrients

cells cannot synthesize them so they must be obtained through our diet, essential amino acids (20 used to build protein, 9 cannot be synthesized)

Malnutrition

result from chronic undereating, especially up to age 2 years; child lacks nutrients necessary for the chemical reactions of growth and development

Metabolism

all chemical reactions occurring in the body, can be catabolic (break bonds) or anabolic (make bonds). requires the assistance of helper molecules called enzymes (proteins that speeds up chemical reactions)

Catabolic reactions

break down larger structures into smaller ones (bond breaking)

Anabolic reactions

build new structures from smaller subunits (bond building)

Enzyme

protein that catalyzes (speeds up) a chemical reaction

Substrate

molecule to which and enzyme binds and on which it acts

Active site

part of an enzyme binds to the substrate

Activation energy

energy required for a chemical reaction to proceed; enzymes reduce activation energy for chemical reactions, so they happen quicker

Micronutrients

important for survival, but in smaller amounts, important to maintain health, play structural and functional roles into the body Ex: nucleic acids, vitamins, and minerals

minerals

inorganic elements required by organisms for normal growth, reproduction, and tissue maintenance Ex: calcium, iron, potassium, zinc

Vitamins

organic molecules required in small amounts for normal growth, reproduction, and tissue maintenance

Minerals act as cofactors

inorganic micronutrients required to activate an enzyme Ex: zinc, copper, iron

Vitamins act as coenzymes

small organic molecules required to activate enzymes

fossil fuels

sources of oil are finite, take millions of years for oil deposits to replenish, demand for oil will increase over the next 25 years

Algae as fuel

algae have the ability to capture the energy of sunlight and convert it into usable forms of energy, much is in the form of oils ideally suited to making fuel

Biofuels

renewable fuels made from living organisms, include fuels made from algae; algae and plants get energy from the sun, trap energy and store it in molecules, biofuel produced is high in chemical energy (currently expensive to produce)

Energy

capacity to do work, can have many forms such as being stored in chemical bonds, conserved (energy is never created or destroyed, but it can change form)

Potential energy

store energy in chemical bonds

Kinetic energy

the energy of motion or movement

heat

the kinetic energy generated by random movement of molecules or atoms

energy transformation (Second Law of Thermodynamics)

not efficient because each energy transformation loses energy to heat, which is why we need to keep supplying energy to any system. This is why our cars run out of gas and why animals produce heat as a result of all energy transformations

Ex: cyclist takes in potential energy in the form of an energy bar; cyclist digest bar, chemical bonds are broken down, and stored potential energy is released; as the cyclists climbs a hill, potential energy is transformed into kinetic energy and heat.

Photosynthesis

process by which plants and other autotrophs capture the energy of sunlight to make energy-rich molecules(glucose), occurs in chloroplasts (organelles present in cells of plants and algae)

Autotrophs

self-feeders that are able to create their own food and energy from transforming solar energy, sun is the ultimate source of energy for most organisms. Ex: plants and algae

Heterotrophs

obtain energy by eating other organisms

photosynthesis equation

sunlight + water (H2O) + carbon dioxide (CO2) = oxygen (O2) + glucose (C6H12O6); photons of light are absorbed by chlorophyll, electrons in the chlorophyll atoms become ‘excited’, excited electrons help generate an energy-carrying molecules known as ATP, ATP used to make sugar

Light energy

the energy of the electromagnetic spectrum of radiation, made of particles called photons (packets of light energy); photons of different wavelengths contain different amounts of energy and is responsible for color in visible light

Chlorophyll

a pigment present in the green parts of plants, absorbs photons of light energy from most colors of light but it reflects mostly green

carbon fixation

transformation of inorganic carbon dioxide to organic carbon glucose. photosynthesis captures carbon dioxide gas from the air and incorporates carbon atoms into sugar

Obesity

having an unhealthy amount of body fat, called Americas #1 health crisis, occurs over many years, problem of energy imbalance (taking in much more energy than we expend in our activities over time)

calories (lowercase c)

the amount of energy required to raise the temperature of 1g of water by 1*C, 1000 calories = 1 Calorie

Calories (capital C)

equal to 1,000 calories or 1 kilocalorie (kcal); Fat = 9 Calories/gram, Protein = 4 Calories/gram, Carbs = 4 Calories/gram

macromolecules are digested into ___

building blocks or subunits; body uses these to make new molecules and as a source of energy

macromolecules contain different amount of stored energy

fats-9 C/g, Proteins and carbohydrates-4 C/g, Nucleic acids- not a significant source of stored energy

using energy from food

different activities require different amounts of energy; not everyone burns calories at the same rate; genetics muscle mass, and gender all have an effect

balancing intake and use off energy

a healthy diet includes balancing calories from food with calories burned. An imbalance of energy in and out can lead to weight gain or loss

converting energy analogy

to buy things that we want, we cannot usually pay with gold, although gold is valuable. By exchanging for a currency, we can purchase items directly.

Aerobic respiration (requires oxygen)

a series of reactions that converts stored food energy into ATP. Occurs in the presence of oxygen. blood transports glucose from food and oxygen from the lungs. Cells release energy from glucose and captures it in ATP. Blood transports excess carbon dioxide to the lungs and water to the kidneys. Glycolysis, Citric Acid Cycle, Election Transport Chain

Aerobic respiration equation

Glucose (C6H12O6) + Oxygen (O2) = Energy (ATP) + Carbon Dioxide (CO2) + Water (H2O)

Aerobic respiration: Glycolysis

occurs in the cytoplasm, series of reactions that break down glucose into smaller units (pyruvate) and produces 2 ATP

Aerobic Respiration: Citric Acid Cycle

occurs in the mitochondria, series of reactions that helps extract electrons from pyruvate and break it down releasing carbon dioxide (byproduct) from food. NAD+ carries electrons to the electron transport chain to produce ATP.

Aerobic Respiration: Electron Transport Chain

NAD+ molecules bring electrons to fold on the inner membrane of the mitochondria. Electrons flow down the chain of molecules on the inner membrane of the mitochondria. At the end of the chain, oxygen accepts the electrons and combines with hydrogen atoms to form water (byproduct). The flow of electrons powers the production of most of the ATP in aerobic respiration. Produces the most energy but isn’t possible without oxygen.

Fermentation (Anaerobic respiration, when oxygen is scarce)

oxygen consumption exceeds oxygen intake, ETC has no oxygen to receive electrons. Glycolysis occurs in the absence of oxygen. Products now undergo fermentation in the cytoplasm instead of aerobic respiration in mitochondria. Produces a small amount of ATP and lactic acid (muscle fatigue and soreness). Ex: Fight or Flight

Glycogen

complex carbohydrate, which is made up of linked chains of glucose molecules. Used in our body as short-term energy storage, stored in muscle and liver cells

the cycle of photosynthesis and respiration

Photosynthesis and respiration from a continuous cycle, with the outputs of one process serving as the inputs of the other

Conservation of energy (First Law of Thermodynamics)

energy is never created or destroyed, but can be converted from form to form

Photosynthesis: Light dependent Reactions

light energy is converted to ATP. water molecules are split releasing oxygen as a byproduct. chlorophyll absorbs photons (light energy), and excites electrons, electrons are used to generate energy carrying molecules (ATP) that are needed in synthesis reactions.

Photosynthesis: the Calvin Cycle or Dark Reactions

carbon dioxide from the air and energy from photo step are used to convert CO2 into glucose.

ATP (adenosine triphosphate)

cellular energy currency. type of nucleic acid, like DNA and RNA. When cells need energy, ATP is broken down (3rd phosphate group is removed) To use it, the cells break the ATP bonds, releasing stored energy, which can then be used in chemical reactions. It is used anytime a muscle contracts or a neuron fires.

Triglyceride

stored in fat cells. Cells convert fats, amino acids, and sugars into triglycerides. Used for long term energy storage