Unit 1: Molecules to Organisms
Identify and define the two types of feedback loops and provide examples of each.
What are:
1. Negative Feedback: This is when the body senses a stimulus and responds by returning the body to a specific set point. Examples: Blood glucose regulaiton, thermoregulation, gas exchange.
2. Positive Feedback: This is when the body senses a stimulus and responds by amplifying a signal until the stimulus is gone. Examples: Blood clotting immune response, contractions during labor.
What are the base pairing rules in DNA and RNS?
DNA: A with T, C with G.
RNA: A with U, T with A, C with G.
Define what natural selection and evolution are.
Natural selection is the process in which traits are selected for in a population through selective pressures. Evolution is the genetic changes in species over long periods of time.
What are the equations for photosynthesis and cellular respiration?
(a) Water + Sunlight + carbon dioxide --> oxygen + glucose
(b) Oxygen + glucose --> carbon dioxide + water + ATP
How is passive transport (facilitated diffusion) assisting in the digestion and absorption of glucose into cells to maintain homeostasis?
Through digestion, large sugar molecules are broken down into smaller glucose molecules. The pancreas then releases insulin as the body senses blood glucose increase, and then insulin binds to the insulin receptor to open the GCP allowing glucose into cells from areas of HIGH concentration to LOW concentration so cellular respiration can take place.
Identify the location of and summarize how these events occur in the cell:
(a) Transcription
(b) Translation
(a) Transcription occurs inside of the nucleus and is when RNA polymerase attaches to the DNA molecule to create the mRNA blueprints needed at the ribosome.
(b) Translation occurs in the cytoplasm at the ribosome and is when the mRNA transcript attaches to the ribosome and is read to then develop the amino acid sequence needed for the primary structure of a protein.
What are the four selecting factors?
(a) Variation - Within a population genetic variation is present giving rise to varying traits and their effectiveness.
(b) Competition - Organisms surviving in the wild must get resources such as food, water, or shelter before other organisms do in order to survive and reproduce.
(c) Adaptations - Through the genetic code adaptations that are beneficial will help organisms out compete other organisms and are more likely to get passed on.
(d) Selection - Weeding out non beneficial traits through selective pressures leads to more beneficial traits being passed onto offspring in the next generation.
What cell structures complete photosynthesis and cellular respiration? BONUS POINTS FOR plant adaptations and body systems!!!
(a) Chloroplast (bonus: guard cell, stomata)
(b) Mitochondria (bonus: circulatory, respiratory, digestive systems)
Develop a model to show how osmosis occurs in cells in the following environments:
1. Hypertonic solution
2. Isotonic Solution
3. Hypotonic solution
Your model should include the cell membrane and arrows showing the movement of water into or out of the cell.
1. Hypertonic solution: Water leaves the cell because there is more salt in the env
2. Isotonic: Dynamic equilibrium
3. Hypotonic: Water will enter the cell because there is more salt inside of the cell.
1. Insertion: A base pair is added to the genetic sequence causing a frameshift. (AAA --> ATAA)
2. Deletion: A base pair is removed from the genetic sequence causing a frameshift. (AAA --> AA)
3. Substitution: A base pair is changed in the genetic sequence. (AAA --> ACA)
Summarize what a homologous structure is. Why are homologous structures good evidence for evolution?
A homologous structure is a bone, organ, or adaptation that is present among many species overtime, but may not function the same. These structures share position, orientation, and composition amongst organisms, their presence across multiple species suggest common ancestry. They are good evidence for evolution because if two organisms share similar structures, then they may be closely related, especially if the structures share the same position and orientation.
What is ecological succession? What are the stages?
1. Pioneer community 2. seral stage 3. climax community
What is mitosis? How does this process help maintain homeostasis?
Mitosis is a form of asexual reproduction in which cells synthesize DNA to then split and form two genetically identical daughter cells. This can help the body maintain homeostasis because it helps with wound healing and growth.
What is gene regulation? Can you provide an example?
Gene regulation is when genes can be turned on or off due to environmental conditions allowing the cell to then produce a protein or stop the production of a protein. Examples include cellular differentiation and the lactase enzyme genes!
Identify a genetic analysis technique used in science and summarize how it works.
Gel electrophoresis is a commonly used genetic analysis tool in which restriction enzymes cut up DNA into smaller genes which are then added into a gel where an electrical current passes through it separating the genes by size!
Develop a model of an energy pyramid with trophic levels and explain the rule of 10%
The rule of 10 explains how energy is lost in ecosystems as you increase trophic levels because organisms have to complete life process and maintain homeostasis.
Models should include arrows and tropic levels!
Identify and summarize the three step of sexual reproduction and identify the locations in which they occur in the male or female reproductive systems.
1. Meiosis - The formation of gametes (sperm/egg) in the testes/ovaries.
2. Fertilization - the combining of gametes in the fallopian tubes of the female reproductive system to create the diploid zygote.
3. Implantation and development - The newly formed zygote attaches to the uterine lining (endometrium) to then undergo growth through mitosis and cellular differentiation.
How does sexual reproduction increase genetic variation and why is that beneficial for populations in biology?
Sexual reproduction increases genetic variation due to recombination, the mixing and matching of chromosomes during sexual reproduction. Two sets of DNA are being combined to create a unique offspring. This helps populations in biology because more traits will be present increasing the likelihood of survival.
Why is genetic evidence better than structural evidence.
Genetic evidence is stronger because genotype determines phenotype. If DNA between organisms is the same, they probably produce similar proteins and have adapted similarly too.
How is carbon cycled through ecosystems?