College Level Bio - Exam #1: Intro to Bio, Biochem, Digestive System, Cellular Respiration, and Photosynthesis

What are the properties shared by all living things? (Note: my grouping of properties of life differs a little from the book. That won’t matter on the exam. Just be able to explain the properties of life and don’t worry if they add up to 8).

1. Organization: organisms are highly organized structures

2. Sensitivity/response to stimuli: respond to - or + environments

3. Reproduction: DNA (genes) to pass to offspring

4. Evolution and adaptation: traits evolve to allow better organisms to thrive in particular environments

5. growth and development: genes direct growth and development, immature —> adult

6. regulation and homeostasis: organisms require regulatory mechanisms to coordinate internal functions

7. energy processing: all organisms require energy to fuel activites

What is a hierarchy?

an arrangment/classification of things according to relative importantness or inclusiveness

What does it mean that living things or living systems are often arranged hierarchically?

It means that all living things are essentially connected, and contained within a larger group

Arrange the following living things, components of living things, and/or living systems in the correct hierarchical order: populations, species, atoms, cells, macromolecules, communities, ecosystems, molecules, tissues, cell components (or organelles), multicellular organisms, biosphere, organs

atoms, molecules, marcomolecules, cell components, cells, tissues, organs, mulitcellular organisms, populations, species, communities, ecosystem, biosphere

Define the term science.

science is the study of the universe in all aspects, always subject to change and examination with better evidence

Define the term biology.

Biology is the study of life

How are atoms, elements, and matter related?

Atoms make up elements, and elements make up matter. Matter is essentially anything that takes up space.

What are protons, neutrons, and electrons? Where is each found in an atom? How do they differ in their electrical charges?

Protons are positively charged and neutrons are neutrally charged, they make up the nucleus of an atom. Electrons are part of the outer shells/rings of the atom, being negatively charged

How do electron shells fill? How does this contribute to the formation of chemical bonds?

the innermost shell is able to hold 2 electrons, 2 and 3 are able to hold 8. Atoms are most stable when their outermost shell is full and thus contributing to the formation of chemical bonds because

What are the 3 types of chemical bonds? How do the three differ?

Ionic bond: a bond between ions, the anion donates an electron to the cation

Covalent: bond where atoms share an electron

Hydrogen bonds: between - and + H ions, if a polar covalent bond has an H, the shared electron is pulled towards the other nucleus, making the charge of the H slightly positive

What are ions? What is the difference between an atom and an ion?

Ions are atoms that do not have an even amount of protons and neutrons, causing them to be electrically charged

What is the difference between nonpolar and polar covalent bonds?

non-polar: electron is shared evenly

polar: electron shared unevenly because the shared electron(s) are pulled towards the nucleus of one atom

Briefly describe hydrogen bonds?

weak bonds between H atoms and other molecules

What are the 4 important properties of water?

1. Water is polar: allows it to bond with other polar substances and itself

2. Water is an excellent solvent: dissolves polar molecules

3. Water has a high heat capacity/stabilizes temp: the breaking and reforming of the H bonds causes water to absorb heat and release it slowly

4. Water is cohesive and adhesive: h2o stick together and to other substances

Why are certain molecules hydrophobic or hydrophilic?

Water is polar, meaning it can form h bonds with other polar substances, making them hydrophilic. Meanwhile non-polar substances are unable to do so, making them hydrophobic

How does water stabilize temperature?

In water’s liquid form, the H bonds of the h2o molecules constantly break and reform in higher temperatures. The broken H bonds absorb that heat to reform, causing the water to essentially slowly absorb and release heat.

How does the structure of water differ when it is a liquid, solid (ice), or gas?

Solid (Ice): The H bonds form a lattice structure due to the lack of heat that make the h bonds break and reform.

Liquid (Water): The H bonds constantly break and reform

Gas (Water Vapor): The H bonds are subjected to such high temperatures that they are unable to reform and only break, evaporating into a gas

How does water act as a solvent?

Water acts like a solvent b/c charged particles of solute form H-bonds with surrounding h2o molecules, which disrupt the ionic bonds and separates them in spheres of hydration

What does it mean that water is cohesive? Give an example from nature that illustrates how water is cohesive.

Water being cohesive means that it can stick to itself. An example would be water droplets collecting on grass. Cohesion causes the water to collect into little droplets

What does the pH scale measure? Which pH values indicate that a substance is an acid and which pH values indicate that a substance is a base

The pH scale measures the amount of H ions in a solution. A substance is acidic with the more H ions it has (1-6), and a substance is more basic with the less H ions it has/the more OH ions it has (8-14)

What are buffers? Why are they are important in living things?

Buffers help maintain the pH in our bodies, as they resist change in pH by absorbing or releasing H or OH ions. This is important in living things because cells can only tolerate a certain pH, which buffers help maintain

In which situation would a buffer contribute hydrogen ions (H⁺) and in which situation would a buffer contribute hydroxide ions (OH^-)?

When a solution is getting too acidic, a buffer would contribute OH ions to it. When a solution is getting too basic, a buffer would contribute H ions to it

What is a macromolecule?

it is a large organic molecule (polymer) necessary for life as they make up major cell parts

What are the 4 types of biological macromolecules? What are the basic functions of each type?

1. Carbohydrates: energy storage (glucose), structural support

2. Proteins: enzymes, protection, storage, transport, cell regulation, membrane structure, etc

3. Lipids: long-term energy storage, insulation, cell membrane, components of hormones

4. Nucleic acids: genetic information carrier for cell instructions and functions

What are some examples of important polysaccharides found in living things?

Glucose, starch (plant glucose storage), Glycogen (animal glucose storage), Cellulose (plant cell wall), Chitin

What is a common polysaccharide that humans cannot digest?

Cellulose

What does it mean for a protein to become denatured? What can cause a protein to become denatured?

A denatured protein is a protein that loses its original shape due to changes in temp or pH, this in turn causes either temporary or permanent loss of function

Briefly describe the scientific method

It is a way to prove educated guesses through experimentation and observation

Define the term hypothesis

an educated guess

What is the difference between a hypothesis and a theory?

a theory is an explanation for a broad amount of research while a hypothesis can be proven wrong and tested through research

What is a variable?

they are things expected to change in an experiment

What is a control in an experiment?

a control is when the Independent variable (the variable the experimenter changes) is set to its default or zero

What are the 3 statements of the Unified Cell Theory?

1. All living things are made up of one or more cells

2. Cells are the basic units of life

3. All new cells come from pre-existing cells

What are the similarities between eukaryotic and prokaryotic cells? Which structures are shared by both cell types?

• DNA

• Plasma membrane

• Ribosomes

• cytoplasm

• Also consider: cell wall (plants and bacteria/archaea only), flagella

What are the differences between eukaryotic and prokaryotic cells? Which structures differ between them?

Eukaryotic cells have membrane bound organelles while prokaryotic cells don’t

Which two domains (major groups of organisms) make up the prokaryotes?

Bacteria and Archaea

Name 3 types of organisms that we have talked about in class that are included in the eukaryotes.

Animals, plants, fungi

What are the similarities and the differences between plant cells and animal cells? Which structures do they share?

They have membrane-bound organelles, and, DNA, Plasma membrane, Ribosomes, cytoplasm

What are the differences between plant cells and animal cells? Which structures exist in one and not the other?

• Plant cells: Cell wall, central vacuole, chloroplasts

• Animal cells” Lysosomes

What are the functions of the following cell structures (that exist in both prokaryotic & eukaryotic cells): flagella, ribosomes, plasma membrane, cell wall?

• Flagella: used to aid in locomotion

• Ribosomes: center of protein synthesis

• Plasma membrane: divides inner cell structure into other extracellular fluid

• Cell wall: made up of cellulose and provides sturcual structural support

What is an organelle?

Organelles are small structures in the cell that have specialized functions

Describe the basic structure of the plasma membrane. Briefly explain the Fluid Mosaic Model.

The plasma memebrane is made up of the phospholipid bilayer, with hydrophilic heads and hydrophobic tails. It is considered to be like a mosaic because of the proteins and carbohydrates scattered around.

Briefly describe the functions of the following organelles:

• Nucleus

• Mitochondria

• Chloroplasts

• Lysosomes

• Endoplasmic reticulum

• Golgi apparatus

• Central vacuole

• Nucleus: houses DNA

• Mitochondria: powerhouse of the cell, site of ATP production and cellular respiration

• Chloroplasts: site of photosynthesis

• Lysosomes: disposal, destroys pathogens

• Endoplasmic reticulum: Modifies proteins and synthesizes lipids and steroid hormones. SER: detoxification of metabolic by-products, drugs, and alcohol

• Golgi apparatus: sorts, tags, and packages proteins and lipids from ER for distribution

• Central vacuole: only in plant cells, 30-80% water, stores other substances

What is the difference between active transport and passive transport?

Active transport uses ATP, going from low to high concentration while passive doesn’t need ATP and goes from a high to low concentration

Describe the process of diffusion. 

Diffusion is the process of molecules moving from a high to low concentration till equilibrium is achieved

Describe the process of osmosis.

it is the movement of water from a low to high concentration of solutes

What is the difference between diffusion and osmosis? 

Osmosis is the movement of water, diffusion of the movement of solute

What is a concentration gradient?

the difference between concentrations of like molecules in 2 regions, to which osmosis and/or diffusion takes place to make a balance

What are the 4 basic functions of the cytoskeleton?

1. Helps the cell maintain its shape

2. Keeps organelles in place

3. Separates chromosomes in cell division

4. Moves cytoplasm and vesicles within cell

What is the difference between autotrophs & heterotrophs?

Autotrophs make their own c-based food while heterotrophs consume other organisms to obtain c-based food

What were the different types of autotrophs and heterotrophs that we discussed in class?

• autotrophs: plants (photoautotrophs)

• heterotrophs:

  • herbivores: eat plants

  • carnivores: eat other animals

  • omnivores: eat both

  • detritivores: eat non-living organic material

What are the 4 steps of food processing?

1. Ingestion: swallowing food

2. Digestion: breaking down food

3. Absorption: done by cells lining digestive tract

4. Elimination: undigested food passes out of digestive tract

Why is digestion necessary?

It is necessary because food molecules are often too large for our cells to access for energy, so digestion breaks the food molecules down into a form that the cells can use for energy

List (in sequence) the parts of the alimentary canal that we discussed in class.

Food enters mouth, esophagus channels food to stomach, stomach churns and grinds food, chemical digestion and absorption occurs in intestines, undigested material is eliminated through the anus

Define peristalsis. What is the function of peristalsis?

It is the contraction and retraction of the muscles lining the digestive tract in only one direction

What is the difference between mechanical digestion & chemical digestion? Where does each occur in the alimentary canal?

Mechanical digestion is the physical breakdown of food, like the teeth smashing or grinding food. This makes it easier for chemical digestion, which uses enzymes to break down complex molecules to absorbable nutrients. Mouth, stomach, and small intestines do both

What is the function of each of the following structures in the digestion of food?

• oral cavity (mouth)

• esophagus

• stomach

• small intestine

• liver

• pancreas

• large intestine

• Mouth: in charge of breaking down food by grinding and smashing and tearing, exposing more SA for digestive enzymes in the saliva which neutralizes acids and lubricates food

• Esophagus: directs food from mouth into stomach

• Stomach: breaks down food with gastric juice and kills most bacteria and microbes, it churns food and in small portions it lets the chyme into the SI

• SI: Absorption of nutrients from chyme, breaking does larger molecules into smaller ones to do so with the help of the liver and pancreas

• Pancreas: helps digest proteins

• Liver: gets nutrients from small intestines thru blood and it removes excess glucose and stores it as glycogen. and aids in digestion of fat

• LI: Directs undigest material out of the body and reaborbs h2o to futher compact it.

Which characteristic of the small intestine allows it to be so effective at absorbing nutrients?

It is villi that expose more surface area for nurtient to get absorbed by

Briefly describe how toxic substances are detoxified in the liver (include the role of the smooth endoplasmic reticulum). You do not need to know the diagram of the liver that shows toxins entering the liver and exiting as waste.

Liver cells have an abundant amount of SER, which is the organelle responsible for detoxifying the cell. SER contains enzymes that allow for toxins to be eliminated easily and exit as urine.

What causes diarrhea?

The lining of the large intestine is inflamed, causing it unable to absorb water from the feces, making it leave the body all watery.

What are the negative health implications of diarrhea?

This is dangerous because it causes a loss of important vitamins and minerals

What causes constipation?

The large intestine having slow peristalsis, causing the poop to be stiffer as the LI sucks more and more water out

What are the main components of human feces?

75% h2o 25% solid waste (can be bacteria, plant fibers, bile, etc)

At which points do buffers play important roles in the digestive system?

Buffers are used in saliva to protect teeth and kill bacteria. The pancreas also uses buffers to help neutralize food that just came out of the stomach

Explain why having a high surface area to volume ratio is advantageous in parts of the body whose function is absorption.

It is advantageous because the more SA a substance has, the more space it has to be absorbed faster and more effectively.

Explain how the body digests lactose

Lactose is brought to the small intestines, where an enzyme called lactase breaks lactose into 2 sugar molecules, glucose and galactose which is absorbed by SI

What are the 3 basic things that animals (like us) get from food?

• fuel: to power activities

• organic molecules: to build animals own molecules

• essential molecules: substances the body cannot make and must get from food

Define metabolism.

the chemical reactions that happen in a cell that either consume or generate energy

What is the difference between an anabolic pathway & a catabolic pathway? Give an example of each.

• anabolic: consumes energy, creates larger molecules from simpler ones. ex: creation of glucose in plants

• catabolic: generates energy, breaks down larger molecules into simpler ones. ex: break down of glucose

What is the basic chemical formula for cellular respiration (you won’t be asked to write this out on the exam, but you might be asked to recognize it)?

C6H12O6 + 6O2 —> 6H20 + 6CO2 + energy (ATP)

How does ATP can act as the cell’s principal energy carrier (or ‘rechargeable battery’)? Make sure to include the fact that high energy chemical bonds between phosphate groups take energy to create and release energy when broken.

Chemical bonds have a lot of potential energy within them because it takes energy to create them, so that energy used to create them can be released as kinetic energy. With ATP, the 3rd phosphate group has a high amount of energy within its bond because it takes a high amount of energy to attach them. That energy is used to fuel activities

After the phosphate bond is broken to release energy, how does ADP become ATP (i.e., how is ADP ‘recharged’ to ATP)?

ADP goes back to ATP by adding the third phosphate group back on

Where does the energy come from to recharge ADP to ATP? That is, how is that energy generated by the cell?

Digestion of food gives energy to recharge ATP, which is done through cellular respiration

Is the chemical energy in chemical bonds potential energy or kinetic energy? Briefly explain your answer.

It is potential energy because the chemical energy in bonds is ‘resting’, using energy to stay in place and has the potential to do work.

How does activation energy relate to the function of enzymes?

Activation energy is the energy needed to start chemical reactions. It is often too high for the body to do naturally, requiring different temperatures or pH that the body cannot handle, so enzymes lower that energy significantly.

Briefly describe what an enzyme is and why it is so important to living things.

Enzymes allow for the chemical rxs the body needs to still occur within the body’s normal limits.

What is a substrate with respect to enzymes?

Substrates are the molecules that bind to an enzyme , to which the enzyme makes the breaking down or formation of chemical bonds occur more easily

What is the basic chemical formula for aerobic respiration (you won’t be asked to write this out on the actual exam)?

same as 70: C6H12O6 + 6O2 —> 6H20 + 6CO2 + energy (ATP)

What is the basic function (purpose) of cellular respiration?

Cellular respiration produces ATP to give the body energy for activites

What are the 3 main steps of cellular respiration?

1. Glycolysis

2. Citric Acid Cycle

3. Oxidative Phosphorylation

What is the relative amount of ATP produced in each of the 3 stages of cellular respiration?

• G: 2 ATPS

• CAC: 2 ATP

• OP: 34 ATP

What molecule enters glycolysis? What are the products of glycolysis (you do not need to know the names of the electron carriers)?

6 C- glucose into 2 3-C pyruvate sugar molecules

What are the products of the Citric Acid Cycle (you do not need to know the names of the electron carriers)?

for each molecule of glucose, CAC makes 4 co2, 2 ATP, and 6 high energy electron carriers

In which organelle does the Citric Acid Cycle take place?

Mitochondria

Why is the Electron Transport Chain important?

It is important because it is the final and most ATP producing step of Aerobic Respiration

Why is O₂ (oxygen) important in the Electron Transport Chain (i.e., why is O₂ important in cellular respiration)?

It is the final electron acceptor in the ETC, and without it the electrons can be removed from the system and the ETC would stop, meaning no production of ATP

Where does the oxygen necessary for cellular respiration come from?

From the air we breathe in

In which of the three steps of cellular respiration is the greatest amount of ATP produced?

Oxidative Phosphorylation

Why is chemiosmosis important in cellular respiration?

It allows for H ios to diffuse back into the matrix of the mitochondria. The energy released from this movement is used to attach the 3rd P group back onto the ADP and turn it into ATP

What is the origin of the carbon atoms in the CO₂ (carbon dioxide) that is released as a byproduct/waste product of cellular respiration? How is the CO₂ released by the body?

The CO2 comes from the C in Glucose that was broken down and then released as you exhale

91. What were the types of photoautotrophs highlighted in class?

plants, algae, cyanobacteria

What is the basic chemical formula for photosynthesis (you won’t be asked to write this out on the exam, but you might be asked to recognize it)?

6CO2 + 6H20 —> C6H12O6 + 6O2

How is glucose stored in plants?

It is stored as starch

In which part of the plant does most photosynthesis typically take place?

in the leaves, but it can be any green part of the plant

What is the function of chloroplasts?

Chloroplasts are the sites of photosynthesis

What is the function of stomata?

tiny openings on the bottom surface of leaves that responsible for regulating gas exchange, co2 in, o2 and water vapor out

Which wavelengths of light are absorbed by plants? What pigment molecule absorbs the light?

Chlorophyll pigment absorb violet-blue and red light and therefore reflect green light to the human eye

In which organelle does photosynthesis take place?

Chloroplasts

What are the products of the 2 stages of photosynthesis – the Light-dependent Reactions & the Calvin Cycle?

LDR: ATP, NADPH (energy carrier), O2 (waste product), CC: Glucose (from LDR products and CO2)

Some of the details about the light-dependent reactions that you should know:

1. What is produced by the light-dependent reactions? 

2. How is light energy is absorbed?

3. Why is the splitting of a water molecule important?

4. How is oxygen released?

5. Why is the electron transport chain important?

6. Why are the electrochemical gradient and chemiosmosis important?

1. ATP, NADPH (energy carrier), O2 (waste product)

2. It is absorbed when a photon is absorbed by a chlorophyll molecule, causing an electron to break free to other chlorophyll molecules

3. h20 split is used to replace the missing e

4. o2 is released as a waste product from the splitting of water.

5. The energy of the electrons passsing down the ETC fuels active transport of H ions against their concentration gradient (from outside to inside) from storoma to thylakoid, then chemiosmosis to make ATP (and NADPH)

6. They represent a stored form of energy within cells, allowing them to generate ATP