Cell Transport
A substance moves from an area of high concentration to low concentration without using cellular energy. What type of transport is occurring?
Passive Transport/ Diffusion
Binary fission is primarily associated with what type of organisms?
Prokaryotes, such as bacteria.
Because the cell membrane allows some substances to cross while preventing others from crossing, it is described using this term.
What is selectively permeable?
A cell is placed in a solution and water moves into the cell, causing it to swell. Is the surrounding solution hypertonic, hypotonic, or isotonic?
Hypotonic
What must happen to bacterial DNA before binary fission can be completed?
The DNA must be replicated.
These molecules make up most of the cell membrane and are arranged in two layers.
Phospholipids
A cell has 10% solute inside and is placed in a solution containing 25% solute. Predict the direction water will move and explain why.
Water moves out toward the higher solute concentration
A disease enters a population of genetically similar organisms produced through asexual reproduction. Explain why the disease could spread rapidly through the population.
Because there is little genetic variation, many individuals may have similar susceptibility to the disease.
Which type of reproduction can occur very quickly?
Asexual Reproduction
A phospholipid contains these two major regions: one that interacts with water and one that avoids water.
hydrophilic phosphate head and hydrophobic fatty acid tails
Two identical cells are placed in different solutions. Cell A gains mass while Cell B loses mass. Compare the solutions surrounding the two cells and explain the movement of water responsible for these results.
Cell A is in a hypotonic solution while B is in a hypertonic solution
What major advantage does sexual reproduction provide regarding offspring?
Increased Genetic Variation
A bacterial population increases from 100 → 200 → 400 → 800. Explain why this pattern supports binary fission rather than sexual reproduction
Binary fission causes one bacterial cell to divide into two, resulting in rapid doubling of the population.
A glucose molecule cannot pass directly through the phospholipid bilayer, so it moves through a protein channel from an area of high concentration to low concentration without using ATP. What type of cell transport is occurring?
facilitated diffusion
A cell contains a lower concentration of sodium than its environment but continues moving sodium out of the cell. Determine whether active or passive transport is required and justify your answer
Active transport because sodium is moving against its concentration gradient
Population A reproduces asexually and increases from 10 organisms to 1,000 organisms very rapidly. A sudden environmental change occurs and 95% of the population dies. Explain how the same reproductive strategy that helped the population grow rapidly may have contributed to its decline.
Asexual reproduction allowed rapid population growth but produced little genetic variation. When conditions changed, few organisms may have possessed traits that allowed them to survive.
Population A contains high genetic variation. After the environment becomes significantly hotter, some individuals survive while others do not. Explain how sexual reproduction may have contributed to the survival of the population.
Sexual reproduction produced genetic variation, increasing the chance that some individuals possessed traits that helped them survive the environmental change.
Scientists discover an organism that reproduces asexually when environmental conditions are stable but switches to sexual reproduction when conditions become stressful. Explain why using both strategies could increase the species' long-term survival.
Asexual reproduction allows rapid population growth when conditions are favorable, while sexual reproduction increases genetic variation when changing conditions make variation beneficial.
Scientists change the shape of a specific protein channel in a cell membrane. After the change, a substance that normally crosses the membrane can no longer enter the cell. Use the relationship between membrane structure and function to explain the results.
the shape and structure of a protein channel determine which substances can pass through it; changing the channel's shape can prevent the correct substance from using the channel?