Midterm #1 (1-5) Flashcards
What are the characteristics/properties of life/living organisms?
- Order and organization
- Evolutionary adaption.
- Response to environment.
- Ability to regulate.
- Energy processing.
- Growth and development.
- Reproduction.
Example of order and organization
Hierarchical structure (molecules, organelles cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems)
Example of evolutionary adaption
Darwin’s finches, peppered moths
Example of response to environment
Migration and hibernation
Example of ability to regulate
Sweating when warm and shivering when cold to bring body back to the regular temperature
Example of energy processing
Plants doing photosynthesis
Example of growth and development
Humans growing through the same stages (foetus baby child teen young adult adult elder)
Example of reproduction
Asexual: binary fission
Sexual : sex
What are the 10 levels of organization?
Molecules
Organelles
Cells
Tissues
Organs
Organs systems
Organisms
Populations
Communities
Ecosystems
What is systems biology?
The understanding of interaction and relationships within biological systems
(Interactions within a cell, not each individual protein or gene but how they interact with each other)
What’s reductionism
Studying complex structures by breaking it up into simple exponents
(Focussing on single heart cells or single proteins)
What are the two types of cells?
Prokaryotic
Eucaryotic
What is the difference between a prokaryotic cell and a eucaryotic cell?
Prokaryotic: simpler without membrane-brown, organelles or nucleus (DNA is in the nucleoid region) Generally, smaller and reproduces asexually (bianary fission)
Eucaryotic more complex with membrane bound, organelles, like the nucleus and mitochondria can reproduce asexually and sexually (fungi, protist, plants, and animal cells)
What are chromosomes
Chromosomes are thread like structures located in the nucleus made up of DNA and proteins. Humans have 46 chromosomes arranged in 23 pairs with one set from each parent 22 pairs of AutoZone and one pair of sex chromosomes (XX, XY)
What is DNA?
DNA (deoxyribonucleic acid): carries genetic information/blueprint. contains instructions for making proteins,
What are genes?
Segments of DNA that contain instructions for building specific proteins
What is the genome?
All the genetic information and organism has
What’s evolution?
The process which species change overtime explaining similarities and differences between living organisms
What is a negative feedback loop
Negative feedback loops counteract a change, bringing a system back to its normal state
(Ex: Your body sweating to cool you off when too hot)
What is a positive feedback loop
Amplifies changes driving the system away from its natural state
(Ex: blood cells creating a blood clot when the body gets an injury to stop the blood from flowing out of the body)
What are the three domains of life?
Bacteria : prokaryotic cells, simple, unicellular, no nucleus, diverse metabolic pathways
Archaea: prokaryotic cells, simple, unicellular, no nucleus, distinct genetic and biochemical pathways
Eukarya: complex, can be both Uni and multicellular organism, with a nucleus
What is a hypothesis?
A explanation that’s testable through experiments (EX: plants grow taller with more sunlight.)
What are the characteristics of a theory?
A broader explanation supported by a large body of evidence from observations and experiments (EX: the theory of evolution explains the diversity of life on earth, supported by fossils and genetic evidence.)
Why are control groups important?
They provide a baseline to compare the effects of what’s being tested
What are the four major categories of organic molecules in organisms?
Carbohydrates: provide energy and structural support
Proteins: perform various functions like catalyzing reactions, and building tissue
Lipids: store energy, and make up the cell membrane
Nucleic acid: store and transmit genetic information
What’s a dehydration reaction?
Joins two molecules together by removing a water molecule commonly forming larger molecules, like sugar or proteins
What is a hydrolytic reaction?
Breaks down a larger molecule by adding water commonly used in digestion to split carbohydrates, proteins and fats into simple sugars, amino acids and fatty acids
Name the monomers that starch, glycogen and cellulose are made of
Starch and glycogen are made up of a-glucose monomers (alpha) while cellulose is made up of B – glucose monomers (beta)
What are the functions of starch, glycogen cellulose and chitin?
Starch and glycogen: energy storage in organisms
cellulose and chitin: provide structural support in plants and animals
How do you unsaturated and saturated fatty acids differ?
Saturated fats form, no double bonds between carbon forming a straight chain making them solid at room temperature (EX butter)
unsaturated fats: form one or more double bonds forming a chain with kinks and bends, between carbon and are liquid at room temp (plant fish oils)
What are the functions of fats
Buoyancy: to keep organisms who live in the water, floating
Padding : to protect organisms and their organs
Insulation : to keep organisms warm
Describe the structure of phospholipids
Hydrophilic head: made of choline phosphate and glycerol
Hydrophobic tails : One tail being straight, the other, having a kink due to double bond
What are the three main groups of amino acids?
Amino group
Carboxyl group
R group (side chain)
What are the four levels of protein structure?
Primary structure: linear sequence of amino acids in a protein, determine by genetic encoding
secondary structure: folding patterns, such as alpha Helices and beta sheets stabilized by each h bonds
Tertionary structure: the overall three dimensional shape of a protein formed by interactions among amino acids chains
Quartinary structure assembly of multiple polypeptide chains into a functional protein complex held together by various interactions
What are the three components of monomers that make up nucleic acid?
Nitrogenous base: pyridamines- cytosine (C), Thymine in DNA (T), Uracil in the RNA (U)
Purines- Adanine (A), Guanine (G)
Ribose sugar: deoxyribose in DNA, ribose in RNA
Phosphate group: backbone of DNA and RNA, connects nucleotides, PO4
How are DNA and RNA different?
DNA: double helix red, 3’ to 5’
RNA: single strand red 5’ to 3’ can form complex 3-D structures through base pairing
What are the 6 functions of membrane proteins?
Transport: move substances across the membrane via channels carriers or pumps
Receptors: respond to signalling molecules, allowing cell communication
Enzyme activity: catalyze biochemical reactions at the membrane
Cell recognition: identify different cell types for immune response and tissue formation
Structural support: attached to the cytoskeleton to maintain cell shape
Inter cellular joining: connects adjacent cells, facilitating communication, and cohesion
What is selective permeability?
The ability of a cell membrane to allow certain substances to pass while blocking others helping maintain homeostasis by regulating the exit and entry of nutrients, ions and waste. This is achieved with the lipid by layer and membrane proteins which control movement based on size charge and solubility.
What is a concentration gradient?
The difference in concentration of a substance between two areas where a substance is more concentrated in one area than another. This gradient causes the movement of substances to go from higher to lower concentration until equilibrium reached (diffusion), which is essential for transporting materials across the cell membrane.
What are carrier proteins?
Membrane proteins that help transport specific proteins across the cell membrane they bond into a molecule then they change shape and then finally release it on the other side. They can function in both positive and active transport.
What is active transport?
Requires energy (ATP) move substances against the gradient (low to high), opposes equilibrium, includes and secondary active transport
What is passive transport?
No energy required, move substances down the gradient (high to low), aims for equilibrium, include simple and facilitated diffusion, as well as osmosis
What is simple, diffusion and facilitated diffusion
Simple diffusion: direct movement of small or nonpolar molecules (from high to low concentration) through the lipid bilayer rate of transport, depends on the gradient and the molecule
Facilitated diffusion: uses carrier proteins to help move, larger, or polar molecules (from low to high concentration) through the lipid bilayer rate of transport may be faster due to carry proteins, but limited by their availability
Difference in plant an animal cells
Animal cells: no cell wall (only plasma membrane), don’t perform photosynthesis therefore no chloroplast, has small vacuoles (if any), shapes irregular and varies in shape
Plant cells: rigid cell wall, contains chloroplast for photosynthesis, large central vacuoles, shape is usually rectangular
Describe the nucleus (structure and function)
Structure: nuclear envelope (double membrane with pores that control substances exchange), neucleoplasm (gel like substance inside the nucleus),
chromatin (DNA and proteins that condense to form chromosomes during cell division),
nucleolus [dense region where RNA is produced and ribosomes are assembled.]
Function: genetic material storage (houses DNA, which contains instructions for protein, synthesis, and genetic information),
regulation (controls cell activities by regulating gene expression),
ribosome production (produces rRNA for ribosome assembly, essential for protein synthesis.)
What are the five themes of biology?
Organization: wife is structured in a hierarchial manner from molecules to ecosystems with emergent properties at each level
Information: genetic information in DNA guides, growth, development, and functioning and his past from one generation to the next
Energy and matter: living organisms require and transform energy and matter to grow, develop and maintain life
Interactions: organisms interact with each other and their environment affecting biological systems and influencing evolution
Evolution: evolution explains the unity and diversity of life as species, change overtime through natural selection and adaption
What is a cell and what do all cells have?
A cell is the smallest unit of
life all cells have:
Plasma membrane: controls what enters and leaves the cell
Cytoplasm: jelly like substance were reactions happen
DNA: contains genetic instructions
Ribosome: makes proteins
What is emergent properties?
New traits that appear when parts work together, which aren’t seen in the individual parts for example in individual cells can’t pump blood, but the heart as a whole can
What is bioinformatics?
The use of computers and software to analyze and interpret biological data like DNA sequences and protein structures
Why do organisms need negative feedback
Organisms need negative negative feedback to maintain homeostasis, keeping their internal environment stable
What is the biological definition of species?
A group of organisms that can inter breed and produce fertile offspring in natural conditions members of a species share, similar characteristics and genetic make up
Why do finches on the Galapagos islands have different shaped beaks?
Due to adaptation to their specific food, sources variations in beak shape, allow different species to exploit different types of food, such as seeds insects, or flowers this diversity helps them survive and reproduce in their unique environments illustrating evolution through natural selection
Explain how evolution can explain both the unity and the diversity of various lifeforms
Evolution explains the unity of life through common ancestry were species share similarities. It counts for diversity via natural selection leading to unique adaptations that helps species survive in different environments.
Natural selection depends on certain conditions name a few and what would happen if the condition wasn’t met
Variation: if not met, no traits selection, limiting evolution
Heritability: if not met, beneficial traits can’t improve future generations
Differential survival and reproduction: if not met, equal chances reduce the impact of natural selection
Competition: if not, abundant resources, lesson natural selections effects
A hypothesis must be_____ and______
Testable and refutable
Using a specific example, explain the steps of scientific method
Observation: noticed that plants seem to grow better under sunlight than under artificial light
Question: does the type of light source affect plant growth
Hypothesis: if plants are grown under sunlight, then they will grow taller than those grown under artificial light
Experiment: set up two groups of identical plants, one exposed to sunlight, and the other to artificial light both groups have the same water and soil conditions
Data Collection: measure and record the height of the plants over several weeks
Analysis: compare the growth data of both groups to see which plant grew taller
Conclusion: determine if the hypothesis is supported or refuted based on the data if plants under sunlight grew taller, the hypothesis is supported
Communication: share the findings in a report or presentation
What is the difference between a control group and an experimental group?
The control group is not exposed to the experimental treatment and serves as a baseline for comparison while the experimental group is subjected to the treatment being tested. The control group helps isolate the effect of the treatment on the experimental group, allowing for a clear conclusions about the treatments impact.
What are some examples of scientific theories?
Theory of evolution: explains how species change overtime through natural selection and adaptation, resulting in the diversity of life
Cell theory: states that all living organisms are composed of cells, and cells are the basic unit unit of life
Play tectonics describes the movement of earths, lithospheric plates, explaining earthquakes, volcanoes, and the continental drift
- a. Organic molecules are:
Organic molecules are carbon-based compounds that typically contain hydrogen and are often associated with living organisms.
- b. How the first organic molecules could have formed before life appeared on Earth (hint: Miller experiment):
The first organic molecules could have formed through chemical reactions between simple gases like methane, ammonia, hydrogen, and water, triggered by lightning or UV radiation, as demonstrated in the Miller-Urey experiment.
- Macromolecules are:
Macromolecules are large, complex molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.
- a) Covalent bonds are:
Covalent bonds are strong chemical bonds formed when two atoms share pairs of electrons.
B0. How many covalent bonds can each atom of C, H, N, O form?
• Carbon (C) forms 4 covalent bonds, Hydrogen (H) forms 1, Nitrogen (N) forms 3, and Oxygen (O) forms 2.
- What is so important about Carbon that makes it a base of life on Earth?
• Carbon’s versatility allows it to form four covalent bonds, creating complex and stable molecules essential for life, including long chains and rings.
5a. Isomers are:
• Isomers are molecules with the same molecular formula but different structures or arrangements
5b. Why do we care which isomer of a given molecule we are dealing with?
:
• Different isomers can have distinct chemical properties and biological effects, making their identification crucial for function.
- Name and describe the 3 types of isomers that we discussed in class.
• Structural isomers differ in the connectivity of atoms.
• Geometric isomers have different spatial arrangements due to restricted rotation (cis-trans).
• Enantiomers are mirror images of each other, often affecting biological activity.
- Draw the structure and name the 7 biologically important functional groups in Figure 4.10
1 Hydroxyl (-OH)
2 Carbonyl (>C=O)
3 Carboxyl (-COOH)
4 Amino (-NH2)
5 Sulfhydryl (-SH)
6 Phosphate (-PO4)
7 Methyl (-CH3)
- Four major categories of organic molecules:
1 Carbohydrates
2 Lipids
3 Proteins
4 Nucleic acids
- What are polymers?
• Polymers are large molecules made by linking repeating smaller units called monomers through covalent bond
10a. What is a dehydration reaction?
• A dehydration reaction is a chemical process where two molecules are joined by removing a water molecule, forming a covalent bond.
10b. What’s a hydrolysis reaction?
• A hydrolysis reaction breaks a covalent bond by adding a water molecule, splitting a polymer into monomers.
- Match these two reactions from P.10 with a) synthesis b) breakdown of molecules.
• Dehydration reaction: synthesis.
• Hydrolysis reaction: breakdown.
What are carbohydrates
• Carbohydrates are organic molecules consisting of carbon, hydrogen, and oxygen, serving as energy sources and structural components.
- Explain what monosaccharides, disaccharides, and polysaccharides are; give examples of each of these.
• Monosaccharides are simple sugars (e.g., glucose).
• Disaccharides are two monosaccharides linked (e.g., sucrose).
• Polysaccharides are long chains of monosaccharides (e.g., starch).
- Name the type of covalent bond that forms between two sugar molecules
Glycosidic bond.
- Name the monomers that starch, glycogen, and cellulose are made of
• Starch: α-glucose
• Glycogen: α-glucose
• Cellulose: β-glucose
- State the functions of starch, glycogen, cellulose, and chitin.
• Starch: Energy storage in plants.
• Glycogen: Energy storage in animals.
• Cellulose: Structural support in plants.
• Chitin: Structural support in fungi and arthropods.
- What important trait do lipids share?
• Lipids are hydrophobic, meaning they do not mix well with water.
- What are fats (triglycerides) composed of
• Fats are composed of three fatty acids attached to a glycerol molecule
- Fatty acids:
• Fatty acids are long hydrocarbon chains with a carboxyl group at one end.
- How do unsaturated fatty acids differ from saturated ones?
• Bonds: Unsaturated have double bonds; saturated have only single bonds.
• Shape: Unsaturated are bent; saturated are straight.
• Liquidity at room temperature: Unsaturated are liquid; saturated are solid.
21a. Why do animals use fats and not polysaccharides for long-term energy storage?
• Fats store more energy per gram due to their dense, hydrophobic nature, making them efficient for long-term storage.
21b. Why do plants use oils for some purposes instead of starch?
• Plant oils are lighter and provide a compact energy source, beneficial for seed dispersal and growth.
- State three functions fats can perform in animal bodies.
• Energy storage, insulation, and protection of organs.
- Describe the structure of phospholipids.
• Phospholipids have a glycerol backbone, two fatty acid tails, and a phosphate group attached to the third carbon
- Phospholipids are described as amphipathic. What does this mean?
• Amphipathic means they have both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.
- Phospholipids are an important component of what biological structure?
Cell membranes.
- Steroids:
• Steroids are lipids with a four-ring carbon structure, functioning as hormones or membrane components.
- Importance of cholesterol:
• Steroids are lipids with a four-ring carbon structure, functioning as hormones or membrane components.
- Proteins are composed of monomers or building blocks known as:
Amino acids.
- Draw the general structure of two such monomers (so you can recognize one if shown on an exam).
• Amino acid structure includes an amino group, a carboxyl group, and a unique side chain (R-group).
- In q. 29, mark atoms on these two monomers that would be subject to dehydration to form a peptide bond
• The amino group of one and the carboxyl group of the other are involved in dehydration
31a. What are the three main groups of amino acids?
1 Nonpolar.
2 Polar.
3 Charged (acidic/basic).
31b. Can you tell to which of these 3 groups an amino acid belongs by its structure?
• Yes, based on side chain properties: hydrophobic, hydrophilic, or charged.
Name and explain the 4 levels of protien structure
1 Primary: Sequence of amino acids.
2 Secondary: α-helices and β-sheets.
3 Tertiary: 3D folding of a single polypeptide.
4 Quaternary: Multiple polypeptides assembling.
1a. State the 3 parts of the Cell Theory.
1 All living organisms are composed of one or more cells.
2 The cell is the basic unit of structure and organization in organisms.
3 All cells arise from pre-existing cells.
1b. What were Robert Hooke’s contributions to cell biology?
1 Coined the term “cell” after observing cork tissue under a microscope.
2 Built one of the earliest compound microscopes.
3 Published observations in Micrographia (1665).
ects:
1c. What were Antoni van Leeuwenhoek’s scientific contributions?
1 Developed powerful single-lens microscopes.
2 Discovered microorganisms, calling them “animalcules.”
3 Observed bacteria, sperm cells, and red blood cells for the first time.
2a. Explain the following microscopy terms:
• Magnification: The process of enlarging the appearance of an object.
• Resolution: The ability to distinguish two close objects as separate entities.
• Contrast: The difference in light intensity between an object and its background, enhancing visibility.
2b. What does the transmission electron microscope allow us to see?
1 Internal cell structures, such as organelles.
2 Fine details like membranes and molecular complexes.
2c. What can be seen with a scanning electron microscope?
1 Surface details of cells and tissues.
2 3D images of specimens.
2d. What is cell fractionation? Why is this technique used?
Cell fractionation separates cellular components by size and density. It is used to study organelles and their functions in isolation.
3a. In which Domains of Life are prokaryotic organisms found?
Prokaryotes are found in the Domains Bacteria and Archaea.
3b. What structures do both prokaryotic and eukaryotic cells have?
1 Plasma membrane.
2 Cytoplasm.
3 Ribosomes.
4 DNA.
3c. Draw a prokaryotic cell. Label the structures and state their functions.
(You can provide a sketch with labeled structures like the nucleoid, ribosomes, plasma membrane, cell wall, flagella, and capsule.)
4a. What is the major difference between prokaryotic and eukaryotic cells? .
Eukaryotic cells have membrane-bound organelles, including a nucleus, while prokaryotic cells do not
4b. How do prokaryotic and eukaryotic cells compare in size? .
Prokaryotic cells are smaller, typically 1–5 µm, whereas eukaryotic cells are larger, about 10–100 µm
4c. What is the cytoplasm?
The cytoplasm is the gel-like substance within the cell membrane, containing organelles and facilitating biochemical reactions.
5a and 5b. Draw and label animal and plant cells, stating their functions.
(Sketch should include the nucleus, mitochondria, Golgi apparatus, ER, etc., for both, with chloroplasts and vacuoles unique to plant cells.)
5c. What structures are found in plant cells but not animal cells?
1
Cell wall.
2
Chloroplasts.
3
Central vacuole.
5d. Reverse question: What structures are found in animal cells but not plant cells?
1 Lysosomes.
2
Centrioles.
- Describe the structure of the nucleus.
1
Enclosed by a double membrane
(nuclear envelope).
2
Contains nuclear pores for transport.
3
Houses DNA in the form of chromatin.
4 Contains the nucleolus, which synthesizes ribosomes.
Nuclear envelope:
Double membrane that protects the nucleus.
Nuclear pores
Openings in the nuclear envelope for molecule exchange.
• Chromosomes:
DNA molecules organized with proteins, carrying genetic information.
Nucleolus:
Site of ribosomal RNA synthesis.
Nuclear lamina:
Protein network that maintains nuclear shape.
Nuclear matrix:
Scaffold-like structure
providing spatial organization.
8a. What is the function of ribosomes?
Ribosomes synthesize proteins.
8b. What are ribosomes made of?
Ribosomes are made of RNA and proteins.
8c. What are the 2 categories of ribosomes, where are they found, and what do they do?
1 Free ribosomes: Found in the
cytoplasm, synthesize cytoplasmic proteins.
2 Bound ribosomes: Attached to the ER, synthesize membrane and secreted proteins.
9a. What is the endomembrane system?
A network of membranes including the nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, and plasma membrane, involved in transport and synthesis.
9b. What are vesicles, and what is their function?
Vesicles are membrane-bound sacs for transporting and storing substances within and outside the cell.
- What are the two types of endoplasmic reticulum, and what are their functions?
1
Rough ER: Protein synthesis and folding.
2
Smooth ER: Lipid synthesis, detoxification, and calcium storage.
11a. Describe the structure and functions of the Golgi apparatus.
A stack of flattened membranes; modifies, sorts, and packages proteins and lipids for transport.
11b. Secretory pathway:
1
Proteins synthesized in rough ER.
2
Transported to Golgi.
3
Modified and sent to vesicles for secretion.
- What are lysosomes, and what functions do these structures have?
Lysosomes are organelles containing digestive enzymes to break down waste and recycle materials.
What are vacuoles give three examples and rolls
- Central vacuoles (plants): stores, water and nutrients.
- Contractile vacuole (protists): pumps excess water
- Food vacuole: stores ingested nutrients
- Draw and explain mitochondria and chloroplasts.
• Mitochondria: Site of ATP production via cellular respiration.
• Chloroplasts: Site of photosynthesis in plants.
- Explain the endosymbiont theory.
Proposes that mitochondria and chloroplasts originated from engulfed prokaryotic cells, forming a mutualistic relationship.
- Explain the functions of peroxisomes.
Break down fatty acids and detoxify harmful substances like hydrogen peroxide.
17a. What are the functions of the cytoskeleton?
1
Provides structural support.
2
Enables intracellular transport.
3
Facilitates cell movement and division.
17b. Name and describe the 3 types of protein fibers in the cytoskeleton.
1
Microtubules: Support and transport.
2
Microfilaments: Shape and motility.
3
Intermediate filaments: Structural stability.
Functions of cilia and flagella:
1
Movement of cells or substances.
2 Found on protists, respiratory epithelium (cilia), and sperm cells (flagella).
1a. What is metabolism?
Metabolism is the total of all chemical reactions occurring within an organism to maintain life.
1b. What is a metabolic pathway?
.
A series of interconnected chemical reactions that convert a starting molecule into a product through specific steps, each catalyzed by an enzyme
Catabolic pathways are:
1
Pathways that break down complex
molecules into simpler ones.
2 Release energy stored in chemical bonds.
1d. Anabolic pathways are:
1 Pathways that build complex molecules from simpler ones.
2 Require an input of energy.
2a. Give a definition of energy.
Energy is the capacity to do work or cause change.
What is kinetic energy?
Kinetic energy is the energy of motion, such as moving objects or molecules.
What is potential energy?
Potential energy is stored energy based on position or structure, like chemical bonds.
What are the 2 laws of thermodynamics?
1 Energy cannot be created or destroyed, only transformed (First Law).
2 Energy transfer increases the entropy of the universe (Second Law).
2e. What is free energy?
Free energy is the portion of a system’s energy available to nerform work at constant
What are exergonic and endergonic reactions?
Exergonic reactions: Release energy,
have a negative free energy change, and occur
spontaneously.
• Endergonic reactions: Require energy input, have a positive free energy change, and are non-spontaneous.
4a. What is ATP?
ATP (adenosine triphosphate) is a molecule that stores and transfers energy for cellular processes.
4b. How does ATP hydrolysis perform cellular work?
ATP hydrolysis releases energy by breaking the bond between its terminal phosphate group, driving endergonic reactions and cellular processes.
4c. Describe the ATP cycle.
ATP is broken down to ADP and inorganic phosphate during energy-releasing processes, then regenerated from ADP in energy-harvesting pathways like cellular respiration.
5a. What are enzymes, and what do they do?
Enzymes are biological catalysts that speed up chemical reactions by lowering activation energy without being consumed.
Most enzymes are ______; however, some are RNA moles
Protiens
Activation energy
The energy required to start a chemical reaction
Transition state
A high energy unstable intermediate in a chemical reaction
Substrate
The specific reactant that it enzyme binds an act upon
Active site
The region of a enzyme where the substrate binds and the reaction occurs
Induced fit
The enzymes active site changes shape to better fit the substrate
Cofactors
Non-protein, molecules, or ions that assist enzyme function
Coenzymes
Organic cofactors often derived from vitamins that assist enzymes
Explain how enzymes carry out their function
Enzymes bind substrates at their active sites lower activation, energy, stabilize, the transition state and facilitate the conversion of substrates into products
What environmental factors affect enzyme activity what examples did we discuss?
Temperature: optimal temperature increases activity extreme temperature can denature enzymes
PH: each enzyme functions best at a specific pH range
Inhibitors: competitive noncompetitive molecules reduce enzyme function
Competitive inhibitors
Bind to the active site of the enzyme, competing with the substrate and preventing its binding
Non-competitive inhibitors
Binding to a different site on the enzyme, altering its shape and reducing its activity
Name three types of cellular work made possible by ATP
One mechanical work [muscle contraction] transport work (pumping ions membrane)
chemical work (endergonic reactions)
Name and describe the two catabolic pathways cells use for ATP production
Aerobic respiration: uses oxygen to fully breakdown, glucose into carbon dioxide and water, generating ATP
anaerobic respiration: occurs without oxygen, using other molecules as final electron acceptors
Explain what redox reactions are
Redox reactions involve the transfer of electrons were one substances oxidized, and the others reduced
How is energy release during a redox reaction?
Energy is released when electrons moved to lower energy states often captured by molecules like naD positive
12a. Why don’t reactions proceed spontaneously in organisms?
High activation energy barriers prevent uncontrolled reactions, which would waste resources or damage cells.
12b. What is the role of enzymes in helping these reactions to happen?
Enzymes lower activation energy, allowing reactions to proceed under controlled conditions.
- Name the three stages of cellular respiration and state where they occur in eukaryotic cells.
1 Glycolysis: Cytoplasm.
2 Citric Acid Cycle (Krebs Cycle):
Mitochondrial matrix.
3
Electron Transport Chain: Inner
mitochondrial membrane.
- What is NAD+ and what is its role in cellular respiration?
NAD* is a coenzyme that acts as an electron carrier, becoming NADH during redox reactions, and shuttles electrons to the electron transport chain.
- Briefly describe the 3 stages of cellular respiration.
1 Glycolysis: Breaks glucose into two pyruvate molecules, producing ATP and NADH.
2 Citric Acid Cycle: Completes glucose breakdown, producing COz, ATP, NADH, and FADH2.
3
Electron Transport Chain: Uses NADH and FADH, to drive ATP production
- What is the role of oxygen in cellular respiration?
Oxygen acts as the final electron acceptor in the electron transport chain, forming water and allowing ATP synthesis.
- Where are the electron transport components found in prokaryotic cells?
In the plasma membrane.
- What are two ways for cells to produce ATP without oxygen?
1
Anaerobic respiration.
2
Fermentation.
19a. What are obligate anaerobes?
Organisms that cannot survive in the presence of axvaen
19b. What are facultative anaerobes?
Organisms that can use oxygen when available but can also perform fermentation or anaerobic respiration.
- Explain the difference between anaerobic respiration and fermentation.
• Anaerobic respiration: Uses an electron transport chain with a molecule other than oxygen as the final acceptor.
• Fermentation: Produces ATP solely through glycolysis, regenerating NAD* without an electron transport chain.
- Describe the two types of fermentation discussed in class.
1 Lactic acid fermentation: Converts pyruvate to lactate, regenerating NAD* (e.g., in muscle cells).
2 Alcohol fermentation: Converts pyruvate to ethanol and COz, regenerating
NAD* (e.g., in yeast).
