Midterm Bio Review
Biology: The Study of Life.
Evidence: The collected body of data from experiments and observations.
Quantitative Observations: Observations involving numbers, such as counting or measuring.
Qualitative Observations: Observations that are not easily counted or measured, such as color or texture.
Inference: Logical interpretation based on prior knowledge, experience, or evidence.
Hypothesis: A suggested, testable answer to a well-defined scientific question or a possible, testable explanation for observations.
Variable: A factor that changes in an experiment.
Independent Variable: The variable manipulated by the experimenter.
Dependent Variable: The variable responding to the manipulated variable.
Why do scientists only test 1 variable at a time? To guarantee that only that 1 variable is the factor affecting the outcome of the experiment. All other factors must be controlled.
Experimental Group: The group in an experiment that is manipulated. It contains the independent variable.
Control Group: The group in an experiment that experiences no manipulation. It does not contain the independent variable.
Scientific Theory: An explanation of some part of the natural world that has been thoroughly tested and is supported by a significant amount of evidence from observations and experiments.
Scientific Law: A description of a natural relationship or principle, often expressed in mathematical terms, and supported by a significant amount of evidence.
What hypothesis did Dr. Semmelweis test? If the doctors washed their hands after an autopsy, diseases would not spread as easily.
Was his hypothesis proven to be correct? Explain. Yes, he was correct. Once handwashing was implemented, when doctors would finish an autopsy and then wash their hands before visiting a living patient, the number of deaths decreased significantly.
List the 6 steps in the Scientific Method
1. Make an observation.
2. Ask a question.
3. Form a hypothesis
4. Make a prediction based on the hypothesis.
5. Test the prediction.
6. Iterate/Repeat: Use the results to make a new hypothesis or prediction.
What is the big idea from today’s reading? An introduction to biology and the proper way to conduct an experiment using the Scientific Method.
List 2 examples of how science is limited.
1. The types of questions science can answer are limited.
2. Human bias.
Explain spontaneous generation. The idea is that living things can form from non-living things.
Provide an example of spontaneous generation. When the meat was left out, maggots were formed from the nonliving meat.
What scientist challenged the law of spontaneous generation? Francesco Redi.
What did he find? He found that when the meat was left out, but isolated, no maggots formed.
Microorganisms: Living creatures that are too small to see with the naked eye.
Scientist Louis Pasteur proved what? He proved that microorganisms cannot spontaneously generate.
How could a scientific law that has been supported by hundreds of years of experiments be wrong? The experiments were flawed.
Abiogenesis: The idea that long ago, very simple life forms spontaneously appeared through chemical reactions.
Some scientists wanted their theory on spontaneous generation to be true. What did they do? They claimed that spontaneous generation occurred in microorganisms. They got away with this because microorganisms were not understood well at this point in time.
What is the big idea from today’s reading? Experiments completed incorrectly can lead to scientific laws, once thought true, to be proven false.
1st Criterion for Life: All living things consist of: cells.
Cells: The smallest units of an organism that are considered to be alive.
Unicellular: This means single-celled.
Multicellular: This means many-celled.
2nd Criterion for Life: All living things: grow.
Cells grow by: enlarging or dividing.
Organisms need what to live? Energy.
3rd Criterion for Life: All life must be able to do what with their surroundings that powers all life functions? Absorb energy and convert it.
What is this called? Metabolism.
Metabolism: The sum total of all processes in an organism that convert energy and matter from outside sources and use that energy and matter to sustain the organism’s life functions.
Anabolism: The sum total of all processes in an organism that use energy and simple chemical building blocks to produce large chemicals and structures necessary for life.
Catabolism: The sum total of all processes in an organism that break down chemicals to produce energy and simple chemical building blocks.
Photosynthesis: The process by which green plants and some other organisms use the energy of sunlight and simple chemicals to produce their own food.
Autotrophs: Organisms that are able to make their own food.
Herbivores: Organisms that eat only plants.
Carnivores: Organisms that eat only organisms other than plants.
Omnivores: Organisms that eat both plants and other organisms.
Heterotrophs: Organisms that depend on other organisms for food.
A large number of organisms on Earth can be classified into 2 categories:
1. Autotrophs
2. Heterotrophs
4th Criterion for Life: When external conditions are changing, all living organisms must maintain a: stable internal balance.
What is this called? homeostasis.
Homeostasis: The maintenance of stable internal conditions.
Birds and mammals are able to regulate their internal body temperature. What is this called? Endotherm.
Reptiles rely on the external environment to help maintain their body temperature. What is this called? Ectotherm.
Endotherm: Organism that is internally warmed by a heat-generating metabolic process.
Ectotherm: Organisms that lack an internal mechanism for regulating body heat.
5th Criterion for Life: To sustain life, an organism must have the ability to do what 2 things in its surrounding area? Sense and respond to changes.
Receptors: Special structures that allow living organisms to sense the conditions of their internal or external environment.
6th (Final) Criterion for Life: All life forms do what? reproduce.
Asexual Reproduction: Process by which a single organism produces genetically identical offspring. The offspring receives all its DNA from one parent.
Sexual Reproduction: Process by which two parents produce genetically different offspring. The offspring receives a combination of DNA from two parents.
Inheritance: The process by which physical and biological characteristics are transmitted from the parent(s) to the offspring.
Mutation: An abrupt and marked change in the DNA of an organism compared to that of its parents.
What is DNA? The set of instructions contained in chromosomes that arrange the chemicals that make-up life in just the right way to produce a living system.
What is the big idea from today’s reading? What life is made up of and what is needed to sustain life. Also touches on DNA and reproduction.
International System of Units: The metric system; the most widely used system of measurement in science.
What are the most used microscopes? Light Microscopes.
Compound Light Microscope: A microscope that shines light through a specimen using two lenses to magnify an image.
A compound light microscope can be used to study what 3 things?
1. dead organisms
2. living cells
3. aquatic microorganisms.
Transmission Electron Microscope: A microscope that transmits a beam of electrons through a thinly sliced specimen.
Scanning Electron Microscope: A microscope that passes a beam of electrons over the surface of a specimen.
What is the big idea from today’s reading? The metric system and the different types of microscopes.
Atoms: The basic building blocks of matter.
Matter: Anything that has mass and takes up space (has volume).
Mass: On Earth, if it has mass, it has weight. Matter is anything that has weight and takes up space.
What are the subatomic particles that atoms are made up of? Protons, neutrons, and electrons.
What is the nucleus? The center of the atom; contains the neutrons and protons.
What charge do protons have? Positive charge
What charge do neutrons have? No charge; they are neutral.
What charge do electrons have? Negative charge
Which subatomic particle circles around the nucleus? Electrons.
Are protons attracted to neutrons or electrons? Electrons.
All atoms have an equal number of what? Protons and electrons.
Atomic Number: The number of protons in an atom; unique to each type of atom.
Elements: A collection of atoms that all have the same number of protons.
Periodic Table: A table of the chemical elements arranged in order of atomic number.i.
Isotopes: One of several forms of an element, each containing the same number of protons but a different number of neutrons.
Atomic Mass: The sum of the protons and neutrons in an atom; this makes up the nucleus.
What are radioactive isotopes? Unstable isotopes because the nuclei break down or decay over time. As they break down, they give off radiation.
Molecule: Chemical that results when two or more atoms join together chemically.
The oxygen we breathe is made up of how many oxygen atoms? Two oxygen atoms.
Compound: A molecule that contains atoms of at least two different elements.
Carbon dioxide is the gas produced by humans and other organisms. When is this gas formed? This gas is formed when one carbon atom and two oxygen atoms chemically join together.
Chemical formulas are the abbreviations of compounds. The Carbon Dioxide chemical formula is CO2. C stands for Carbon and O stands for Oxygen. Since there is no number after the C, this indicates 1 atom. Since the O has a 2 after it, that tells us there are 2 oxygen atoms.
In the chemical formula for Methane, CH4…
How many Carbon atoms are there? 1 carbon atom.
How many Hydrogen atoms are there? 4 hydrogen atoms.
In the chemical formula for Glucose, C6H12O6…
How many Carbon atoms are there? 6 carbon atoms.
How many Hydrogen atoms are there? 12 hydrogen atoms.
How many Oxygen atoms are there? 6 oxygen atoms.
What two compounds are formed with Carbon and Oxygen and what is their Chemical Formula?
1. Carbon Monoxide (CO)
2. Carbon Dioxide (CO2)
In small amounts, which one is harmless to humans? Carbon Dioxide
Which one is poisonous to humans? Carbon Monoxide
As seen above with carbon and oxygen, the number of atoms a molecule contains completely changes its chemical makeup. What is another example of this? Oxygen (O2) vs. Ozone (O3).
Explain: Both are made of oxygen but since the number of atoms differs, they are completely different molecules.
How do atoms become more stable? They link together to become more stable.
Ionic Bond: A chemical bond formed when one or more electrons are transferred from one atom to another.
Ion: Positively or negatively charged atom (or group of atoms) resulting from the transfer of electrons.
NaCl=Na is the Sodium atom and Cl is the Chlorine atom.
Together they make what? Table Salt, also known as sodium chloride.
How many Sodium atoms are there? 1 sodium atom
How many Chlorine atoms are there? 1 chlorine atom
Covalent Bond: Chemical bond formed by the sharing of electrons between two or more atoms.
What is the big idea from today’s reading? The structure of atoms; Reading the Periodic Table of Elements.
Cells are the: basic units or building blocks of life.
In 1595, the Janssens invented what? The first compound 2-lense microscope.
In 1855, the “cell theory” was solidified. How? Rudolf Virchow was the first to identify and name leukemia because he observed blood cells under a microscope.
List the 3 facts the cell theory states:
1. All living organisms are composed of cells. They may be unicellular or multicellular.
2. The cell is the basic unit of structure and function in living organisms.
3. Cells arise from existing cells
Cytology: The study of cells.
Characteristics of Cells:
Ingestion: The ability to take in nutrients; this includes absorption, which is the ability to bring dissolved materials into the cell.
Digestion: The ability to break food or nutrients down into simpler forms (by hydrolysis or with the help of enzymes) so it can be utilized.
Respiration: The ability to release energy from the breakdown of food molecules.
Transport: The ability to distribute or circulate molecules from one part of a cell to another.
Homeostasis: The ability to maintain internal stability (also known as regulation).
Synthesis: The ability to combine simple compounds into complex molecules.
Secretion: The ability to release biosynthesized substances.
Excretion: The ability to remove soluble metabolic waste from the cell.
Egestion: The ability to remove non-soluble, undigested waste from the cell.
Irritability: The ability to respond to stimuli.
Movement: The ability to move.
Reproduction: The ability to produce more cells.
There is no such thing as what? A simple life form.
Cells are called organelles; what does this mean? Little Organ
Organelle: A tiny cellular structure that carries out a specific function necessary for the cell to survive.
Prokaryotic Cell: A cell that has no nucleus of other distinct, membrane-bound organelles.
Eukaryotic Cell: A cell with a membrane-bound nucleus and other distinct, membrane-bound organelles.
All cells contain what 4 things?
1. DNA
2. Plasma Membrane
3. Cytoplasm
4. Ribosomes
Plasma Membrane: The semipermeable membrane between the cell contents and the cell’s surroundings.
Cytoplasm: A Jelly-like fluid inside the cell in which the organelles are suspended.
Cytoplasmic Streaming: The motion of cytoplasm in a cell that results in a coordinated movement of the cell’s content.
Ribosomes: Non-membrane-bound organelles responsible for protein synthesis.
What is the big idea from today’s reading? What a cell is and some of its characteristics.
Cells are the basic units of life, exhibiting various structures and functions that enable them to maintain homeostasis and respond to their environment.
Middle Lamella: The thin film between the cell walls of adjacent plant cells.
The nucleus is called what? The control center of the cell.
Nuclear Membrane: A highly porous membrane that separates the nucleus from the cytoplasm.
Chromatin: Long strands of clusters of DNA and proteins in the nucleus of a cell.
Endoplasmic Reticulum (ER): An organelle composed of an extensive network of folded membranes that performs several tasks within a cell.
Rough ER: ER that is dotted with ribosomes.
Smooth ER: ER that has no ribosomes.
Golgi Apparatus: The organelles where proteins and lipids are stored and then modified to suit the needs of the cell.
Vacuole: Larger membrane-bound organelle used for storage of food, water, or waste.
Vesicle: Smaller membrane-bound organelle used mainly for the transport of food, waste, or products synthesized for secretion.
Secretory Vesicle: Vesicle that holds the products of biosynthesis and transports them to the plasma membrane for secretion.
Central Vacuole: A large vacuole that rests as the center of most plant cells and is filled with water.
Lysosome: The organelle in animal cells responsible for hydrolysis reactions that break down proteins, carbohydrates, and some lipids.
Peroxisome: A cell organelle containing enzymes that catalyze the decomposition of fatty acids and hydrogen peroxide.
Mitochondria: Double-membrane-bound organelles in which nutrients are converted to energy.
Plastids: Double-membrane-bound organelles found in the cells of plants, algae, and some protozoa, generally involved in either the manufacture or storage of food.
Chloroplasts: Plastids containing the green pigment, chlorophyll, used in photosynthesis.
Chromoplasts: Plastids containing yellow, orange, or red pigments used in photosynthesis.
Leucoplasts: Nonpigmented plastids that store starches or oils.
Cytoskeleton: A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement.
Microfilaments: Fine, threadlike proteins found in the cell’s cytoskeleton.
Intermediate Filaments: Threadlike proteins in the cell’s cytoskeleton that are roughly twice as thick as microfilaments.
Microtubules: Spiral strands of protein molecules that form a tubelike structure.
Centrioles: Paired organelles that organize fibers required for cell division and are found in animal cells.
Centrosome: A small region near the nucleus that is the main organizing site for microtubules; in animal cells, it contains the two centrioles.
What is the big idea from today’s reading? More details about cells and their parts.
Functions of Cell Parts
Nucleus: The control center of the cell, containing DNA and coordinating cell activities.
Nuclear Membrane: A highly porous barrier separating the nucleus from the cytoplasm, controlling the exchange of materials.
Chromatin: Clusters of DNA and proteins in the nucleus, responsible for packaging DNA and regulating gene expression.
Endoplasmic Reticulum (ER): An extensive network of folded membranes performing various functions, including protein and lipid synthesis.
Rough ER: Ribosome-studded ER that synthesizes proteins.
Smooth ER: Lacks ribosomes; involved in lipid synthesis and detoxification processes.
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Vacuole: A large membrane-bound structure in plant cells for storage of substances such as water, food, or waste.
Vesicle: Smaller membrane-bound structures used for transporting materials in and out of cells.
Secretory Vesicle: Transports biosynthesized products to the plasma membrane for secretion.
Central Vacuole: A large vacuole in plant cells that stores water and helps maintain turgor pressure.
Lysosome: Contains enzymes for breaking down waste materials and cellular debris.
Peroxisome: Contains enzymes that break down fatty acids and detoxify hydrogen peroxide.
Mitochondria: Double-membrane-bound organelles where cellular respiration and energy production occur.
Plastids: Organelles involved in the manufacture and storage of food in plants; includes several types:
Chloroplasts: Contain chlorophyll for photosynthesis.
Chromoplasts: Store pigments for photosynthesis (yellow, orange, red).
Leucoplasts: Store starches or oils.
Cytoskeleton: A network of fibers that supports the cell's shape and aids in movement; includes:
Microfilaments: Thin protein strands involved in cell movement and structural support.
Intermediate Filaments: Provide mechanical support and maintain cell shape.
Microtubules: Hollow proteins that provide structure and facilitate intracellular transport.
Centrioles: Pair of organelles that organize microtubules during cell division in animal cells.
Centrosome: The main organizing center for microtubules near the nucleus, containing centrioles.
ATP stands for Adenosine Triphosphate. This is the energy molecule of cells.
ADP stands for Adenosine Diphosphate. This is the low-energy form of ATP.
Phosphorylation: The transfer of energy when a phosphate group is moved between molecules.
Pigment: An organic compound giving a specific color to plant or animal cells.
Chlorophyll: A group of pigments found in algae, green plants, and cyanobacteria. It is necessary for photosynthesis, allowing for the absorption of energy from light.
All organisms require a constant input of energy.
Most organisms – photosynthesis and/or cellular respiration.
Some – Chemosynthesis – do not require sunlight.
Photosynthesis Goal: Storing Energy
Cellular Respiration Goal: Releasing Stored Energy
ATP is a rechargeable, reusable energy source. It powers most cellular processes.
When ATP powers a cellular process, it loses energy and becomes ADP-the low-energy form of ATP.
Chemical Reactions and Glucose can recharge the ADP so it turns back to ATP.
This recharging process is called: CELLULAR RESPIRATION.
Photosynthesis depletes our supply of ATP.
Cellular Respiration recharges the molecules/ATP.
What is the big idea from today’s reading/video? Photosynthesis and Cellular Respiration.
Stroma: Gel-like fluid found inside the inner membrane of a chloroplast.
Thylakoid: Disk-shaped sac suspended in the stroma of chloroplasts. It is the site of the light reactions of photosynthesis.
Grana: Stacks of thylakoids.
Photosystem: A cluster of chlorophyll and other molecules in the thylakoid membrane that absorbs light energy.
Electron Transport Chain: A service of electron-carrying molecules within a membrane that transfers electrons and releases energy at each transfer.
The Calvin Cycle: Glucose is made from carbon dioxide and high-energy molecules from light reactions.
What is the big idea from today’s reading? More details on photosynthesis.
Remember: ATP is a rechargeable, reusable energy source. It powers most cellular processes. When ATP powers a cellular process, it loses energy and becomes ADP-the low-energy form of ATP. However, due to Chemical Reactions and Glucose ADP can recharge and turn back to ATP.
Aerobic: Requiring Oxygen.
Anaerobic: Without Oxygen.
There are Four Stages of Cellular Respiration. Describe each.
Stage 1: Glycolysis: The first stage of cellular respiration where glucose is split in half.
Stage 2: The Link Reaction: Acid is broken down and a protein is attached.
Stage 3: The Krebs Cycle: The stage of cellular respiration where carbon dioxide is used to complete the breakdown of pyruvic acid molecules, releasing energy.
Stage 4: The Electron Transport Chain (ETC): This is where the abundance of ATP production will occur.
What is the big idea from today’s reading? The stages of cellular respiration.
Fermentation: A cellular process producing ATP without oxygen.
Two Types of Fermentation:
1. Lactic Acid
2. Alcoholic Fermentation
Lactic acid fermentation is the type of glucose breakdown performed by your muscle cells when you are: exercising hard.
Lactic acid fermentation is also performed by some bacteria that make: yogurt, cheese, sauerkraut, pickles, soy sauce, or sourdough bread.
Alcoholic Fermentation is performed mainly by: yeast that makes bread, beer, and wine.
What is the big idea from today’s reading? Fermentation
Genetics: The science that studies how characteristics are passed from parent to offspring.
Genetic Factors: The general guideline of traits determined by a person’s DNA.
Environmental Factors: Those “nonbiological” factors that are involved in a person’s surroundings such as the nature of the person’s parents, the person’s friends, and the person’s behavioral choices. They also include things like exposure to chemicals, molds, extreme weather conditions, and allergens.
Spiritual Factors: The factors in a person’s life that are determined by the quality of his or her relationship with God.
Gene: The basic unit of heredity; a section of DNA that contains the code to produce a protein or a portion of a protein, thereby causing a trait.
Chromosome: Duplicated on pg. 221.
Chromatin: Duplicated on pg. 221.
What is the big idea from today’s reading? Genes and other factors that determine who we are.
DNA Replication: The process by which two identical DNA molecules are produced from one original DNA molecule.
Chromatin: Long strands of clusters of DNA and proteins in the nucleus of a cell.
Chromosome: Condensed threads of chromatin found in the nucleus of the cell.
Chromatid: One of the two identical copies of a replicated chromosome joined by a centromere.
Centromere: The region where two sister chromatids are joined tightly together.
Triplet: A three-base sequence on DNA.
Codon: A three-base sequence on mRNA that codes for a specific amino acid.
Anticodon: A three-base sequence on tRNA.
Excellent DNA Summary from Khan Academy: “DNA is the information molecule. It stores instructions for making other large molecules, called proteins. These instructions are stored inside each of your cells, distributed among 46 long structures called chromosomes. These chromosomes are made up of thousands of shorter segments of DNA, called genes. Each gene stores the directions for making protein fragments, whole proteins, or multiple specific proteins.”
1. DNA is the instruction manual for making proteins.
2. The instructions are stored in each cell and spread out among our 46 long structures called chromosomes.
3. These chromosomes are made up of shorter segments of DNA also called genes.
4. Each gene stores the instructions for making various proteins.
In looking at the big picture, the above video tells us that Mitosis is: A type of cell division done by most of your body cells. If cells didn’t divide, you wouldn’t grow. Mitosis also repairs damaged cells by making more identical cells.
Mitosis: A process of asexual reproduction in eukaryotic cells.
Interphase: The time interval between cellular reproductions.
Cytokinesis: The process, usually following mitosis or meiosis, in which the cytoplasm of a cell is divided in two.
Karyotype: The figure produced when the chromosomes of a species during metaphase are arranged according to their homologous pairs.
Diploid Cell: A cell with chromosomes that come in homologous pairs or two sets of chromosomes.
Haploid Cell: A cell that has only one representative of each chromosome pair or half the total number of chromosomes.
Diploid Number (2n): The total number of chromosomes in a diploid cell.
Haploid Number (n): The number of homologous pairs in a diploid cell (1/2 the total).
Excellent Mitosis Summary from Khan Academy: “Mitosis is used for almost all of your body’s cell division needs. It adds new cells during development and replaces old and worn-out cells throughout your life. The goal of mitosis is to produce daughter cells that are genetically identical to their mothers, with not a single chromosome more or less.”
1. 1st Purpose is to divide cells for growth to occur. This is how the zygote grows into a full-size baby in the womb.
2. 2nd Purpose is that it adds new cells during development and replaces the worn-out or damaged cells throughout your entire life.
3. Goal is to make daughter cells that are genetically identical to their mothers with the exact same number of chromosomes.
In looking at the big picture, the above video tells us that Meiosis: Makes sperm and egg cells also called gametes.
Every human has 46 chromosomes. In meiosis, each gamete only has 23 chromosomes, but when they join to create a human, the chromosomes combine to make 46.
Meiosis: The process by which a diploid (2n) cell forms gametes (n).
Gametes: Haploid Cells (n) produced by diploid cells (2n) for the purpose of sexual reproduction.
Zygote: The result of sexual reproduction when each parent contributes half of the DNA necessary for the offspring.
*A fertilized egg is a zygote. Once the zygote is made, mitosis begins. This is how the zygote grows and develops into a full-size baby.
Tetrad: Two homologous chromosomes consisting of four chromatids, two sister chromatids in each chromosome.
Crossing Over: The exchange of genes between homologous chromosomes.
Excellent Meiosis Summary from Khan Academy: “Meiosis is used for just one purpose in the human body: the production of gametes—sex cells, or sperm and eggs. Its goal is to make daughter cells with exactly half as many chromosomes as the starting cell.”
Meiosis Broken Down:
1. Purpose is to produce gametes/sex cells called sperm (has 23 chromosomes) and eggs (has 23 chromosomes).
2. Goal is to make daughter cells with exactly half the number of chromosomes (23) as the starting cell (46).
3. When the sperm and egg join their 23 chromosomes, the zygote/fertilized egg will have 46 chromosomes.
4. Once the zygote is made, mitosis begins.
Scientific Method
Scientific Method is summarised by OHEATL – Observation, Hypothesis, Experiment, Analyse Data, Theory, Law.
A hypothesis is an untested explanation for an occurrence, while a scientific theory is an explanation that has been tested and verified numerous times. A scientific law is a description of a natural phenomenon that has been tested and verified countless times.
Independent variables are the things that the experimenter changes, and the dependent variables are the variables that are observed to are respond to the independent variable being manipulated.
The limitations of science: science must conform to the scientific method, science is not 100% reliable, science cannot prove anything.
Criteria of Life
Criteria of Life: All living things: Have DNA and Can Reproduce, Have Cells, Require Energy, Undergo Growth, Sense and Respond to Surroundings, Perform Homeostasis.
DNA can be seen with a microscope, and humans have children; cells can be seen under a microscope; plants need the sunlight energy to live – if they are put in the dark they die; all animals grow from babies to adults; when flies fly into a spider’s web, he feels and goes to wrap them up; a lizard maintains stable internal temperatures by sunning himself on rocks when the weather is cold.
Cells are the basic unit of structure and function in all life.
Organisms extract energy from the environment by either producing their own food, eating other organisms, or decomposing dead organisms.
Autotrophs use the process of photosynthesis to produce their own food.
An autotroph is an organism that produces its own food, a heterotroph gains energy from eating other organisms, and a decomposer gains energy from breaking down dead organisms.
The process of cellular respiration converts food into a useable form of energy.
Metabolism is the sum of processes by which organisms use energy and matter from outside itself to sustain life inside itself. Anabolism is all metabolic processes that build, while catabolism is all metabolic processes that break down.
Homeostasis is when organisms maintain stable internal conditions. For example, cells monitor the amount of salt in the cytoplasm and adjust it if it is too high or too low.
Sense and Response enable organisms to avoid danger and take good opportunities to gain energy. A receptor is any organ or gland that allows an organism to sense its surroundings.
DNA allows organisms to pass on their traits through reproduction and acts as a manual telling the body how to make proteins and which proteins to make.
Asexual reproduction involves only one parent cell and produces two daughter cells identical to the parent cell, while sexual reproduction involves two parent cells, producing daughter cells that are different to either parent cell.
Tools of Biology
The metric system is used in science because it is simple, logical, and well-known. It provides a standard system of measurement all around the world.
Tables and graphs can be used to present data in a simple and informative way and to spot trends.
Types of microscopes: Compound Light Microscope: Focuses light with lenses. Can view living organisms in colour. Scanning Electron Microscope (SEM): Passes a beam of electrons over the surface of an organism or object. Can only view dead organisms and cannot show colour. Transmission Electron Microscope (TEM): Passes a beam of electrons through a thinly sliced specimen. Can only view dead organisms and cannot show colour.
The TEM has the greatest magnification, while the Compound Light Microscope has the least magnification.
Atoms are the smallest units of matter, while molecules are made up of multiple atoms bonded together and mixtures are made up of multiple types of molecules mixed together.
An atom is made up of protons (+ charge) and neutrons (neutral charge), which are located in the nucleus, as well as electrons (- charge), which orbit the nucleus.
The number of atoms of each element in a molecule is indicated by the subscript underneath that element’s symbol.
a) The formula for sucrose is C12H22O11, so it has 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms.
b) In a molecule of caffeine (C8H10N4O2), there are 8 carbon atoms, 10 hydrogen atoms, 4 nitrogen atoms, and 2 oxygen atoms.
The atomic number of an element is the number of protons it contains. This number is unique for every element. The mass number of an element is the sum of its protons and neutrons.
An isotope of an element is a form of the element with a non-standard number of neutrons.
In Oxygen-18, there are 8 protons, 10 neutrons, and 8 electrons.
a) Oxygen -15 is an isotope of Oxygen-18.
A covalent bond is a bond between atoms where valence electrons are shared between them, while an ionic bond is formed when one atom gives away one or more valence electrons to another.
Properties of Water
a) Autotrophs (producers) extract energy from the environment by using photosynthesis to make their own food from external energy, usually sunlight.
b) Heterotrophs (consumers) extract energy from the environment by consuming other organisms for food.
c) Decomposers, also known as saprophytes, extract energy from the environment by breaking down dead or decaying matter.
Trophic levels are representations of where organisms are in terms of the food web in a specific ecosystem. Food webs can show us which organisms rely on others for food, and to show relationships between organisms.
History of the Cell Theory
Cellular Structures
Ingestion (taking substances in), digestion (breaking down food), respiration (release energy from breaking down food), transport (moving molecules around the cell), homeostasis (maintain stable internal conditions), synthesis (make complex molecules), secretion (release biosynthesised substances), excretion (remove soluble waste from cell), egestion (remove nonsoluble waste from cell), irritability (respond to external stimuli), movement (move), reproduction (produce more cells).
Ingestion: cell membrane, vesicles, cytoplasm
Digestion: lysosome, peroxisome
Respiration: mitochondria
Transport: cytoplasm, vesicles
Homeostasis:
Synthesis:
Secretion:
Excretion:
Egestion:
Irritability:
Movement:
Reproduction:
Nucleus, ribosomes, Golgi apparatus, cytoplasm, cell membrane, vacuoles, vesicles, cell wall (for plants), lysosome, peroxisome (for animals), centrioles, ER, nucleolus, plastids, mitochondria
All cells have ribosomes, cytoplasm, cell membrane
Nucleus, ribosomes, Golgi apparatus, cytoplasm, cell membrane, vacuoles, vesicles, cell wall, lysosome, centrioles, ER, nucleolus, plastids, mitochondria
Nucleus, ribosomes, Golgi apparatus, cytoplasm, cell membrane, vacuoles, vesicles, lysosome, peroxisome, centrioles, ER, nucleolus, plastids, mitochondria
Phospholipids, proteins, and carbohydrates. The heads of the phospholipids are attracted to water and the tails hate water, so the tails point inwards and the heads point out.
Diffusion is when solutes move from an area of high solute concentration to an area of low solute concentration. Osmosis is when water moves from an area of high water concentration to an area of low water concentration.
Passive transport is when substances are transported without energy and active transport is when substances are transported with energy.
When a plant cell is in a ____ solution, they _____.
Isotonic, are too little.
Hypertonic, shrivel
Hypotonic, are normal
When an animal cell is in a ____ solution, they _____.
Isotonic, are normal.
Hypertonic, shrivel
Hypotonic, lyse, or explode
ATP:
ATP is adenine triphosphate. It has three phosphate groups, and when one breaks off, energy is released. It’s used because it is easy to make it release energy
Photosynthesis:
Light Reactions and Calvin Cycle. In the light reaction, high energy electron carriers are formed, and a few ATP are formed as well. All this occurs in the thylakoid membrane. The Calvin Cyle uses CO2 and H2O and light energy to produce glucose and oxygen gas. This occurs in the stroma of the chloroplast.
In photosystem II, pigment molecules absorb sunlight energy and the electrons in them jump to electron carriers. Water gives its hydrogen’s electrons to the pigments to replace the lost electrons, also forming oxygen gas and hydrogen ions.
During the electron transport train, electrons are passed between proteins to PSI, pumping hydrogen ions from the stroma into the thylakoid space
In photosystem I, the electrons are re-energised.
Oxygen is formed and released in photosystem II.
Carbon Dioxide is used during the Calvin Cycle, during carbon fixation
Cellular Respiration
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The four steps of cellular respiration are glycolysis, link reaction, Krebs cycle, and electron transport chain.
Glycolysis is in the cytoplasm, and the rest are in the mitochondria – link reaction and Krebs cycle are in matrix of the mitochondria, and the ETC is in the folded inner membrane.
Glycolysis produces pyruvic acid, NADH, and ATP, link reaction produces acetyl CoA and NADH, Krebs Cycle produces ATP, CO2, FADH2, and NADH, and ETC produces ATP and H2O.
Carbon dioxide is formed during the Krebs Cycle, and water is formed during ETC.
The ETC produces most of the ATP molecules.
Anaerobic cellular respiration only uses the glycolysis step.
A yeast cell produces ATP and ethyl alcohol at the end of its cellular respiration, while animals cells produce ATP and lactic acid at the end of their cellular respiration.
DNA, Genes, and Chromosomes
The monomers of DNA are nucleotides, which are made up of a deoxyribose and phosphate backbone, with a base attached: either thymine, adenine, guanine, or cytosine. The monomers of RNA are also nucleotides, but with some differences: they are made of a ribose and phosphate backbone with a base attached, either uracil, adenine, guanine, or cytosine.
The DNA molecule is arranged in a double helix structure, with the bases of corresponding nucleotides (A-T, C-G) paired together between the chains of the backbones. Sugar and phosphate groups make up the backbone. The “rungs” of the “ladder” are made up of the base pairs.
DNA is a double helix, while RNA is a single helix. DNA has thymine as its base to pair with adenine, while RNA has uracil. Also, DNA has deoxyribose as the sugar in its backbone, while RNA has ribose.
A gene is a sequence of DNA that codes for a specific protein, or part of a protein. It is the basic unit of heredity.
Chromosomes are the condensed form of chromatin, found in the nucleus of a cell. Chromatids are the chromosome before being duplicated, but after being duplicated, there are two identical chromatids in one chromosome. The centromere of a chromosome is the region where the two sister chromatids join.
DNA Replication
DNA replicates by first being split in two down the middle by helicase, then corresponding base pairs are added by DNA polymerase. Finally, ligase seals all the bonds.
Protein Synthesis
The first step in protein synthesis is transcription, where RNA is made with complementary base pairs to a portion of DNA in the nucleus. Next comes translation, where the RNA is transcribed into proteins in the ribosomes.
In transcription, the DNA is unwound, and mRNA base pairs are added to the exposed DNA bases. This forms an opposite image of the DNA. In translation, the mRNA is paired up with tRNA, which carries amino acids. These amino acids link together to form proteins.
mRNA carries the opposite image of the DNA and travels from the nucleus to the ribosomes. tRNA carries the amino acids and arrives one at a time at the ribosome to add the correct amino acid to the protein chain. rRNA is the RNA that makes up the ribosomes.
What are the 6 common characteristics of Class Aves? 1) Porous, lightweight bones. 2) Toothless beak. 3) Four-chambered heart. 4) Oviparous, amniotic egg with lime-covered shell. 5) Endothermic. 6) Covered with feathers.
Identify the structures of an egg and explain their function. Shell – protects the contents of the egg while exchanging gases with the environment. Albumen (white) – prevents pathogens from growing and reaching the embryo, stores water, absorbs shock, stores proteins. Chorion – membrane enclosing yolk, allantois, and embryo. Allantois – membrane-enclosed sac of blood vessels, allows embryo to respirate and excrete waste. Yolk sac – membrane enclosing yolk. Yolk – nutrients used to sustain the embryo. Amnion – membrane enclosing embryo. Embryo – Developing baby animal.
What are the 5 common characteristics of Class Mammalia? 1) Endothermic. 2) Four-chambered heart. 3) Hair covering skin. 4) Nourish young with milk produced by special glands. 5) Usually viviparous, internal fertilisation.
Identify an egg-laying mammal. What order does it belong to? A platypus is an egg-laying mammal that belongs to Order Monotremata.
Identify a pouched mammal. What order does it belong to? One pouched animal is the kangaroo, which belongs to Order Marsupialia.
What is the difference between marsupials and monotremes? Marsupials are nonplacental viviparous mammals, while monotremes are oviparous.
Explain how the major life functions are carried out in each of the classes.
Day 3, pgs. 642-650
Five Characteristics of Mammals:
1. Hair covering the skin
2. Reproduce with internal fertilization and usually viviparous
3. Nourish their young with milk secreted from specialized glands
4. Endothermic
5. Heart with four chambers
What are some of the functions of hair? Insulation to keep animals warm, camouflage, defense mechanism (porcupine), etc.
Nonplacental Mammals: Babies are not fully developed at birth and continue to develop outside the mother’s uterus.
Placental Mammals: Babies that are provided nutrients via the placenta inside the womb, where they fully develop.
Placenta: A structure that allows an embryo to be nourished with the mother’s blood supply.
Gestation: The period of time during which an embryo develops before being born.
Mammary Glands: Specialized glands in mammals that produce milk to nourish the young.
What does it mean for a mammal to be endothermic? They are able to regulate their own internal temperature and keep it constant.
Mammals are divided into what three groups? Monotremes, Marsupials, and Placenta Mammals.
What are the only two living members of monotremes? Duck-billed platypus and Echidna.
Are marsupials Nonplacental Mammals or Placental Mammals? Nonplacental.
Where does the baby go to finish developing? Their mother’s pouch where they attach to a nipple. This is how they receive the needed nutrients to grow.
The largest group of mammals are: Placental Mammals.