Bio Study Guide - Unit 1 - Sheet1 Flashcards
Questions
A query made to seek information, clarify a concept, or solve a problem in a scientific context.
Hypothesis
A testable idea or prediction based on observations, used to guide scientific experiments.
Prediction
Based on the hypothesis, predict the observable outcome (e.g., string movement).
Test
Conduct the experiment and observe the results.
Analyze
Evaluate the results; compare observations to predictions. Revise hypotheses as needed.
Conclusion
Explain the success or failure of the experiment and the reasons behind it.
Communicate & Collaborate
Share findings and work with others.
Control
The group or condition not receiving the treatment; used for comparison.
Independent Variable
The variable manipulated by the researcher; the presumed cause.
Dependent
The variable measured or observed; the presumed effect; depends on the independent variable.
What was the Early Atmosphere & Climate of Early Earth?
Early Earth had a dense, greenhouse atmosphere (CO2, NH3) due to impacts, volcanism, and radioactive heat, despite a faint young Sun.
Origin of Life
Life likely began in hot hydrothermal vents, utilizing sulfur compounds. Photosynthesis later introduced oxygen, forming the ozone layer and enabling life’s expansion onto land. Early life forms were extremophiles.
Asteroid Bombardment
Significant asteroid impacts occurred, potentially causing extreme heat and affecting geology and early life, but with a relatively modest impact on tectonics.
Extremophiles
Organisms thriving in extreme environments (high/low temperatures, pressures, radiation) demonstrate life’s resilience and adaptability.
Atmospheric Evolution
Early atmosphere: low oxygen, high CO2, likely significant methane. Evolution linked to planetary processes, impacts, magmatism, and the biosphere.
Crustal Evolution
Continental crust formed in stages: mafic oceanic crust, then TTG crust, finally granite. This involved partial melting, fractional crystallization, and likely a magma ocean in the early Earth.
Characteristics of Living Material
- Made up of cells
- Grow and develop
- Metabolize (either anabolize or catabolize molecules) for energy
- Excrete waste products
- Respond to surrounding (stimuli)
- Many move (not all living things move, ie. plants, corals, etc)
- Reproduction
How did Early Earth form?
- Space dust and matter, INORGANIC minerals, metals, ice, accrete to create the planet of molton magma and toxic gases.
- Asteroids and celestial bodies collide into earth and melt
- Atmosphere and lithosphere filled with CO2, H2O, CH4, NH3, S and P
Abiogenesis
The origin of life from non-living matter.
Spontaneous Generation
An outdated belief that living organisms arise spontaneously from non-living matter (Aristotle).
Creationism
The belief that life originated through a supernatural act of creation.
RNA from Sulfur Compounds
A hypothesis suggesting RNA, a precursor to life, formed from sulfur compounds in a primordial soup.
Protective Membranes
The formation of membranes around macromolecules to protect them from harsh environmental conditions.
Cell Formation
The cell membrane is made of phospholipids with water-loving heads and water-fearing tails. It controls what goes in and out of the cell and keeps it stable.
Ozone Layer
Photosynthesis released oxygen, forming the ozone layer, which protected life from UV radiation and allowed life to move from water to land.
Seafloor Processes
Life may have started in deep-sea vents, using sulfur and CO2 for energy, with molecules forming on minerals like pyrite.
Evolution of the Earth
Asteroid impacts in Earth’s early years, especially the late bombardment, likely boiled oceans, leaving only heat-loving organisms.
Biogeochemistry
Early Earth had low sulfate levels in the ocean, which influenced the carbon cycle. Sulfur isotopes in diamonds help understand this.
Earth Accretion and the Giant Impact Hypothesis
Early Earth was molten due to impacts and heat, leading to a “magma ocean” in the mantle.
Are We the First: Was There Life Before Our Solar System
Extremophiles show life’s ability to thrive in extreme environments like deep ocean trenches, hot springs, and frozen areas.
What Was It Really Like on Early Earth
Early Earth had a strong magnetic field, a CO2-rich atmosphere, and frequent meteorite impacts, all affecting life and climate.
When Did Life Develop
Life likely began around 3.5 billion years ago, with oxygen levels rising as cyanobacteria created photosynthesis.
Sharing Electrons
Atoms share valence electrons (electrons in the outermost shell) to achieve a stable electron configuration, often a full outer shell (octet rule).
What is the Strongest Bond?
Covalent bonds are strong and require significant energy to break, contributing to the stability of molecules.
Non-metal Atoms
Covalent bonds typically form between non-metal atoms, which have high electronegativity and strongly attract electrons. Sharing electrons is more energetically favorable than electron transfer between non-metals.
Single Covalent Bond
One pair of electrons is shared between two atoms (e.g., H-H in hydrogen gas).
Double Covalent Bond
Two pairs of electrons are shared between two atoms (e.g., O=O in oxygen gas).
Triple Covalent Bond
Three pairs of electrons are shared between two atoms (e.g., N≡N in nitrogen gas).
Nonpolar Covalent Bond
Electrons are shared equally between atoms with similar electronegativities (e.g., H-H).
Polar Covalent Bond
Electrons are shared unequally between atoms with different electronegativities, creating partial negative (δ-) and partial positive (δ+) charges on the atoms (e.g., H-O in water).
Covalent Bonds in Biology
Covalent bonds are crucial in the structure of biological molecules like proteins, carbohydrates, lipids, and nucleic acids, determining their three-dimensional shape and function.
Water as a Solvent
Water is a powerful solvent due to its polarity, allowing it to dissolve a wide variety of substances.
Importance of Carbon
Carbon’s versatility makes it the building block of life.
Amino Acids
Amino acids are the building blocks of proteins, consisting of a central carbon, a carboxyl group, an amino group, a hydrogen atom, and a variable R group.
Carbohydrates
Carbohydrates are organic molecules made of carbon, hydrogen, and oxygen, primarily used for energy and structure. They include sugars like glucose and starch.
Nucleotides
Nucleotides are the building blocks of DNA and RNA, made of a five-carbon sugar, a phosphate group, and a nitrogenous base, storing genetic information.
What are Phospholipids?
Phospholipids are molecules made of a hydrophilic (water-loving) phosphate head and two hydrophobic (water-fearing) fatty acid tails. They form the basic structure of cell membranes.
Covalent Bonds vs. Hydrogen Bonds:
Covalent bonds are strong intramolecular bonds sharing electrons, while weaker hydrogen bonds are intermolecular attractions between slightly charged atoms.
four primary classes of biomolecules
proteins, carbohydrates, nucleic acids, and lipids.
Polar is…?
hydrophilic, usually has a oxygen molecule
Non Polar is…?
hydrophobic, doesnt contain oxygen
Photosynthesis
The creation of energy by converting sugar in plants.
Photosynthesis Reactants and Products
Products: Glucose (C₆H₁₂O₆) and O₂. –> Reactants: CO₂, H₂O, and light energy.
Importance of 400-700 nm Range
The 400-700 nm range of light is used by plants for photosynthesis, as it contains the visible spectrum of light that plants can absorb efficiently.
Why Plants Are Green
Plants appear green because chlorophyll absorbs red and blue light, reflecting green light.
Trees’ Mass Source
The majority of a tree’s mass comes from carbon dioxide absorbed from the air during photosynthesis.
Explanation of Photosynthesis
CO₂ enters through leaf stomata, and water is absorbed by roots. Glucose is produced as energy for autotrophs, while oxygen supports aerobic organisms.
How is color determined by light’s wavelength?
Color is determined by light’s wavelength, with longer wavelengths being redder and lower in energy, and shorter wavelengths being bluer and higher in energy.
Cuticle
A waxy, waterproof layer covering the epidermis of leaves and other aerial plant parts; reduces water loss.
Upper Epidermis
The outermost layer of cells on the upper surface of a leaf; usually transparent to allow light penetration.
Palisade Mesophyll
A layer of elongated cells beneath the upper epidermis; contains many chloroplasts for photosynthesis.
Mesophyll
The internal tissue of a leaf, consisting of palisade and spongy mesophyll; the main site of photosynthesis.
Spongy Mesophyll
A layer of loosely packed cells beneath the palisade mesophyll; contains air spaces for gas exchange.
Lower Epidermis
The outermost layer of cells on the lower surface of a leaf; contains stomata.
Stoma (Stomata)
Tiny pores on the lower epidermis of leaves; regulate gas exchange (CO2 intake, O2 and H2O release).
Guard Cells
Specialized cells surrounding each stoma; control the opening and closing of the stoma, regulating gas exchange and water loss.
Calvin Cycle
Takes place in the stroma; involves carbon fixation, reduction, and regeneration. CO₂ is converted into G3P using ATP and NADPH, which is then used to create sugars or stored as starch.
Light Reactions
: Occur in the thylakoid membranes; use light energy to produce ATP and NADPH, which are used in the Calvin cycle. Water is split, releasing oxygen.
How do photosynthesis and cellular respiration relate to each other?
Photosynthesis produces the fuel (glucose) and oxidant (oxygen) for cellular respiration.
Cellular respiration produces the reactants (carbon dioxide and water) for photosynthesis
What are complex carbohydrates?
oligosaccharides (3-10 monosaccharides) polysaccharies (11+ monosaccharides)
What are simple carbohydrates?
Monosaccharides (just 1) and disaccharides (2)
How are monosaccharides connected?
Glycocidic bond
Fatty Acids
Long hydrocarbon chains with a carboxyl group at one end; can be saturated (no double bonds), monounsaturated (one double bond), or polyunsaturated (two or more double bonds).
Triglycerides
The most common type of lipid, composed of a glycerol molecule esterified to three fatty acids; primary form of energy storage in animals.
Phospholipids
Similar to triglycerides but with one fatty acid replaced by a phosphate group linked to a polar head group; amphipathic nature makes them vital for cell membranes.
Steroids
Lipids with a four-ring hydrocarbon structure; examples include cholesterol (a cell membrane component) and steroid hormones like testosterone and estrogen.
Saturated Fat
A type of fat with fatty acid chains that have no double bonds between carbon atoms; solid at room temperature.
Unsaturated Fat
A type of fat with fatty acid chains that have one or more double bonds; typically liquid at room temperature.
Which type of fat is easier to break down?
Unsaturated fat because of the doulbe bond
Caloric value of all fat
9
Triglycerides
Lipids that store unused calories and provide energy.
Cholesterol
A waxy, odorless lipid used to build cells, cell walls, and nerves.
HDL
High-density cholesterol.
LDL
Low-density cholesterol.
Lipoproteins
Triglycerides + LDL cholesterol + protein.
Atherosclerosis
A chronic inflammatory disease where plaque builds up in arteries, hardening and narrowing them.
Caloric Value of Fats
9 calories per gram.
Steroids
Four-ring hydrocarbon structures; include\ cholesterol (cell membrane component) and hormones (e.g., testosterone).
What is saturated fat?
Fat with no double bonds, solid at room temperature (e.g., butter, lard, coconut oil).
What is unsaturated fat?
Fat with one or more double bonds, liquid at room temperature (e.g., olive oil, sunflower oil).
What is monounsaturated fat?
Fat with one double bond, considered a healthier option for the heart (e.g., avocado, olive oil, nuts).
What is trans fat?
Unsaturated fats artificially hydrogenated to make them solid, linked to negative health effects (e.g., margarine, processed foods).
Amino Acid
Amino Acid: The basic building block of proteins; contains an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group).
Anabolism
Anabolism: Metabolic pathways that construct molecules from smaller units; requires energy (endergonic).
Catabolism
Catabolism: Metabolic pathways that break down molecules into smaller units; releases energy (exergonic).
Monomer
Monomer: A small molecule that can bond to other identical molecules to form a polymer.
Essential Amino Acid
Essential Amino Acid: An amino acid that cannot be synthesized by the body in sufficient amounts and must be obtained from the diet.
Non-Essential Amino Acid
Non-Essential Amino Acid: An amino acid that can be synthesized by the body.
Cytoplasm
The gel-like substance filling the cell, excluding the nucleus. It contains various organelles and is the site of many metabolic reactions.
Cell Membrane
A selectively permeable barrier surrounding the cell, regulating the passage of substances into and out of the cell. Composed primarily of a phospholipid bilayer with embedded proteins.
Golgi Apparatus
A stack of flattened membrane-bound sacs that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles within the cell.
Lysosomes
Membrane-bound organelles containing digestive enzymes that break down cellular waste, debris, and foreign materials.
Mitochondria
Double-membrane-bound organelles responsible for cellular respiration, generating ATP (adenosine triphosphate), the cell’s main energy currency. Often called the “powerhouse” of the cell.
Nuclear Membrane/Envelope
A double membrane that surrounds the nucleus, separating it from the cytoplasm. It contains nuclear pores that regulate the transport of molecules between the nucleus and cytoplasm.
Nucleus
The control center of the eukaryotic cell, containing the cell’s genetic material (DNA) organized into chromosomes. It also contains the nucleolus.
Ribosomes
Small, non-membrane-bound organelles responsible for protein synthesis. They translate the genetic code from mRNA (messenger RNA) into a polypeptide chain. Can be free in the cytoplasm or bound to the rough ER.
Rough Endoplasmic Reticulum (RER)
A network of interconnected flattened sacs (cisternae) studded with ribosomes. It is involved in protein synthesis, folding, and modification, particularly for proteins destined for secretion or membrane insertion.
Vacuoles
Membrane-bound sacs that store various substances, including water, nutrients, waste products, and pigments. Plant cells typically have large central vacuoles.
Where are proteins manufactured?
Proteins are manufactured by ribosomes.
Identify the primary structure used in cellular respiration.
The primary structure used in cellular respiration is glucose.
Where are the blueprints stored?
The blueprints (genetic information) for cellular structures and functions are stored in the nucleus of eukaryotic cells, specifically within the DNA molecules.
List the macromolecules that make up the semipermeable cell membrane and which structures allow molecules into and out of the cells.
Transport Proteins
Facilitate the movement of specific molecules across the membrane (e.g., channel proteins, carrier proteins).
Receptor Proteins
Bind to signaling molecules, triggering cellular responses.
Enzymes
Catalyze reactions within the membrane.
Structural Proteins
Maintain the integrity and shape of the membrane.
Carbohydrates
These are often attached to lipids (glycolipids) or proteins
(glycoproteins) on the outer surface of the membrane. They play roles in cell
recognition and signaling.
Simple diffusion
Movement of small, nonpolar molecules directly across the lipid bilayer (e.g., oxygen, carbon dioxide).
Facilitated diffusion
Movement of molecules across the membrane with the help of transport proteins (e.g., glucose, ions).
Osmosis
Movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.
Active transport
This requires energy (ATP) and moves molecules against their concentration gradient (from low to high concentration) with the help of transport proteins.
Endocytosis
The cell engulfs extracellular material by forming vesicles.
Exocytosis
Vesicles fuse with the cell membrane, releasing their contents
outside the cell.
Phospholipids
Have hydrophilic heads and hydrophobic tails, forming
a bilayer.
Cholesterol
Maintains fluidity and supports cell communication.
Proteins
Enable molecule transport, communication, and membrane
anchoring.
Selective Permeability:
Non-polar molecules (e.g., oxygen) pass easily.
Polar molecules use transmembrane protein channels.
Plasma Membrane
A selectively permeable membrane that encloses the cytoplasm of a cell, regulating the passage of substances into and out of the cell. Composed of a phospholipid bilayer with embedded proteins.
Semi-permeable
A property of a membrane that allows some substances to pass through while blocking others. The permeability depends on factors like size, charge, and lipid solubility of the substance.
Simple Diffusion
The passive movement of a substance across a membrane from an area of high concentration to an area of low concentration, without the assistance of membrane proteins. Driven by the concentration gradient.
Facilitated Diffusion
The passive movement of a substance across a membrane from an area of high concentration to an area of low concentration, with the assistance of membrane proteins (channel or carrier proteins).
Osmosis
The passive movement of water across a selectively permeable membrane from a region of high water concentration (low solute concentration) to a region of low water concentration (high solute concentration).
Passive Transport
The movement of substances across a cell membrane without the expenditure of energy. Includes simple diffusion, facilitated diffusion, and osmosis. Movement is always down a concentration gradient (high to low).
Active Transport
The movement of substances across a cell membrane against their concentration gradient (from low to high concentration), requiring the expenditure of energy (usually ATP).
Vesicles
Small, membrane-bound sacs within a cell that transport substances. Formed by budding off from membranes and can fuse with other membranes to release their contents.
Phagocytosis
A type of endocytosis where a cell engulfs large solid particles, such as bacteria or cellular debris, forming a phagosome.
Pinocytosis
A type of endocytosis where a cell engulfs extracellular fluid and dissolved substances, forming pinosomes. This is a less specific form of endocytosis compared to phagocytosis.
Glucose Carrier Protein
A transmembrane protein embedded in the cell membrane that facilitates the transport of glucose across the membrane. Different types exist (e.g., GLUT1, GLUT2, GLUT4).
Function
Mediates facilitated diffusion of glucose. It binds glucose on one side of the membrane, undergoes a conformational change, and releases glucose on the other side.
Specificity
Binds specifically to glucose molecules. Other sugars are not transported by these proteins.
Regulation
The activity of glucose carrier proteins can be regulated by factors such as insulin, glucose concentration, and other hormones or cellular signals.
Glucose Solubility
Glucose is highly soluble in water, which is crucial because it needs to be dissolved in extracellular fluid to be transported across the membrane by the carrier protein.
Photosynthesis function and location
Chloroplast, convert light into energy
ATP name
Adenosine - Triphosphate
ATP Cycle
ATP releases 1 phosphate which creates the energy - makes ADP -> ADP abosrbs another phosphate (food) to create ATP
NADH Cycle
NADH plays a key role in cellular respiration, particularly in the electron transport chain, where it donates electrons, helping to generate ATP.
NADH Steps
- NADH donates electrons to the electron transport chain (ETC).
- Electrons pass through protein complexes, pumping protons (H⁺) across the membrane.
- The proton gradient drives ATP synthase to produce ATP.
4.Oxygen accepts electrons and combines with protons to form water. - NADH is oxidized to NAD⁺ and recycled.
Benefits of using ATP and NADH rather than glucose
Glucose is difficult to transport, while ATP and NADH provide bite sized energy
3 steps of cellular respiration
Glycolisis, Krebs Cycle, ETC
Aerobic Respiration
Needs O2 (oxygen), occurs in mitocondira
Anaerobic Respiration
No O2, occurs in cytoplasm
Glycolisis is
Anaerobic Respiration, occurs in cytoplasm, splits glucose into pyruvate, Produces 2 ATP
Energy Payoff Phase
4 ATP are produced, along with 2 NADH, as the molecules are further broken down, resulting in a net gain of 2 ATP.
Energy Investment Phase - Stage 1 Glycolisis
2 ATP are used to phosphorylate glucose and its derivatives, preparing them for breakdown
Krebs cycle
occurs in the mitochondria matrix,citric acid is broken down, releasing carbon dioxide, high-energy electrons, and ATP. For each turn of the cycle, 3 NADH, 1 FADH₂, and 2 ATP are produced
Where does the ETC occur in the mitochondria?
The electron transport chain (ETC) occurs in the inner mitochondrial membrane. The proteins of the ETC are embedded within this membrane.
What chemicals carry electrons to the ETC?
NADH and FADH₂ are the primary electron carriers that deliver high-energy electrons to the ETC. These molecules are produced during glycolysis and the Krebs cycle
Why is oxygen required for aerobic respiration?
oxygen (O₂) is the final electron acceptor in the electron transport chain. Without oxygen, the electrons cannot be passed down the chain, and the process of oxidative phosphorylation (which generates the vast majority of ATP) comes to a halt.
How many ATP molecules can be produced from the ETC?
34 ATP
Products and Reactants of Cellular Respiration
C6H12O6 + O2 -> CO2 + H20 ATP (energy)
