Unit 1
During what part of the cell cycle is DNA copied so that each daughter cell can receive the same genetic information?
S phase of interphase
What molecule provides immediately usable energy for cellular work?
ATP
What is carrying capacity?
The maximum population size an environment can support over time with its available resources and conditions.
A skin cell successfully completes mitosis. What should be true about the genetic information in its two daughter cells?
They should contain essentially the same genetic information as each other and the parent cell.
Complete the energy story with the correct processes:
Sunlight → ______ → glucose → ______ → ATP → cellular work
Photosynthesis and cellular respiration
Why is mitosis important for a multicellular organism?
Mitosis produces new daughter cells with essentially the same genetic information, allowing organisms to grow and replace damaged or old cells.
When ATP releases energy for cellular work, what happens to ATP?
ADP + phosphate (P) - Removing a phosphate from ATP releases energy that can be used for cellular work.
Prolonged freezing temperatures greatly reduces the amount of vegetation and water available to a deer population.
What would most likely happen to the deer's carrying capacity and WHY?
Decrease - The environment now has fewer resources available to support deer.
A plant that has plenty of water and CO₂ is moved from bright light into very low light. What would you predict will happen to its rate of photosynthesis and WHY?
It will decrease. - Less light energy is available to power the light-dependent reactions.
Explain how photosynthesis connects Unit 2 Cellular Energy to Unit 3 Carbon Cycling.
Photosynthesis:
Muscle cells and nerve cells from the same person contain essentially the same DNA, yet they have different structures and functions. What process explains this and how does it do it?
Cell differentiation - Different genes are active/expressed in different specialized cells, resulting in different proteins, structures, and functions.
What happens to energy during photosynthesis? (Describe the flow of energy)
Light energy is transformed into chemical energy that is ultimately stored in sugars such as glucose.
A disease kills many fish in a lake, but the total amount of food, water, and habitat available does not change. What happens to the population AND carrying capacity of the fish population and WHY?
Population size decreased because of disease
The carrying capacity stays about the same because the environment's ability to support fish did not change.
Oxygen suddenly becomes unavailable to a muscle cell. Glycolysis can still occur. What specific process can allow glycolysis to continue temporarily in human muscle cells, and why?
Lactic acid fermentation - Fermentation regenerates NAD⁺, allowing glycolysis to continue producing a small amount of ATP.
A large drought causes a plant population to decrease.
Explain how this ONE change could affect:
Photosynthesis: Total photosynthesis in the ecosystem may decrease because there are fewer plants capturing light energy and taking in CO₂.
Carrying capacity: The herbivore's carrying capacity (K) may decrease because less plant food is available.
Connection:
Drought → plants ↓ → ecosystem photosynthesis/food production ↓ → herbivore resources ↓ → herbivore carrying capacity ↓
A cell develops DNA damage.
Tell me what would happen to this cell if it followed the rules at the checkpoint.
Tell me what would happen to this cell if it DID NOT followed the rules at the checkpoint.
Normally, a checkpoint would stop the cell cycle or apoptosis would occur.
Abnormal - Uncontrolled cell division could produce a tumor/mass of abnormal cells or cancer.
Two cells receive the same amount of glucose. Cell A has plenty of oxygen. Cell B has no oxygen. Which cell can obtain substantially more ATP from the glucose, and why?
Cell A - Oxygen allows aerobic cellular respiration to continue, releasing substantially more usable energy from glucose. Cell B - No oxygen can use fermentation to allow glycolysis to continue, but only a small amount of ATP is produced.
Grass → Grasshopper → Frog → Snake
A disease causes the frog population to decrease. Predict one direct effect and one indirect effect.
Possible Direct: Grasshoppers may increase because fewer frogs are eating them or Snake may decreased because less food (frogs) for the snake.
Possible Indirect: Grass may decrease because the larger grasshopper population consumes more grass.
An invasive plant enters an ecosystem and competes with a native plant for light, water, and space. The invasive plant population rapidly increases. What could happen to the native plant population and organisms that depend on it? Why?
The native plant population may decrease because competition for resources increases. Organisms depending on the native plant for food or habitat may also decrease. - invasive species ↑ → competition ↑ → native plants ↓ → dependent organisms potentially ↓
Two populations of the same plant species live in different environments. Population A receives plenty of sunlight and water. Population B receives much less sunlight but the same amount of water.
Explain how the difference in sunlight could eventually affect:
Less sunlight can decrease photosynthesis, so Population B may produce less glucose. With less glucose available for cellular respiration, less chemical energy is available for ATP production. If plant growth/biomass decreases, less energy is available to herbivores that consume the plants.
A chemical prevents anaphase from taking place. Predict what could happen to the daughter cells.
The chromosomes wont separate which will cause genetic material to not be distributed correctly between the daughter cells.
A substance prevents the light-dependent reactions from producing ATP and NADPH. Predict what will happen to the Calvin cycle and its products?
Calvin cycle wont have the energy it needs to create glucose so sugar production will decrease. - The light-independent reactions/Calvin cycle use ATP and NADPH from the light-dependent reactions to help build sugars from CO₂.
A forest is cleared and much of the removed wood is burned. Give TWO reasons atmospheric CO₂ could increase.
1. Fewer trees means less CO₂ is removed from the atmosphere through photosynthesis.
2. Burning the wood releases stored carbon into the atmosphere through combustion.
A prolonged drought causes plant food to decrease dramatically. At the same time, a disease spreads through an herbivore population. The herbivore population then declines.
Can scientists conclude that the disease alone caused the population decline? Explain.
No. - Both decreased resources from the drought and disease could contribute to the population decline. The evidence does not allow scientists to attribute the entire decline to one factor.
A plant growing in an ecosystem experiences a mutation that causes its cells to divide uncontrollably. Over time, the damaged tissue reduces the plant's ability to perform photosynthesis, and the plant eventually dies.
Explain how this situation connects one concept from EACH unit:
Unit 1 — Cell Division
Unit 2 — Cellular Energy
Unit 3 — Ecosystems
Unit 1: Loss of cell-cycle regulation/checkpoints can lead to uncontrolled cell division.
Unit 2: Reduced photosynthesis means less light energy is transformed into chemical energy/stored in sugars.
Unit 3: Loss of the plant can reduce food/energy available to consumers, affect food-web populations, and potentially affect carbon cycling.