B3 MOVEMENT INTO AND OUT OF CELLS Flashcards
What is diffusion?
The net movement of particles from a region of higher concentration to a region of lower concentration as a result of random movement.
How do some substances move into and out of cells?
By diffusion through the cell membrane.
Why does carbon dioxide leave the cell during aerobic respiration?
Because the concentration inside the cell is higher than the concentration outside.
What factor affects the rate of diffusion related to size?
Surface area.
How does surface area affect diffusion?
The larger the surface area to volume ratio, the faster the rate of diffusion.
What effect does temperature have on diffusion?
Higher temperature increases the kinetic energy of molecules, leading to faster movement.
What is the concentration gradient’s role in diffusion?
Substances diffuse faster with a larger difference in concentration between the two areas.
What happens if there are more particles on one side during diffusion?
There are more particles available to move across.
How does distance impact the rate of diffusion?
Substances diffuse more quickly when they don’t have to move as far.
Fill in the blank: The higher the temperature, the greater the _______ of the molecules.
[kinetic energy]
True or False: A smaller surface area to volume ratio results in a faster rate of diffusion.
False.
What is the definition of osmosis?
Osmosis is the diffusion of water molecules through a partially permeable membrane.
In which direction does osmosis occur?
From a region of higher water potential to a region of lower water potential.
Is energy required for osmosis?
No energy is required—osmosis is a passive process.
How does water move in relation to the cell membrane?
Water moves into and out of cells by osmosis through the cell membrane, which is partially permeable.
What factors determine the direction of water movement in osmosis?
The direction of water movement depends on the water potential inside and outside the cell.
What happens to plant tissues placed in solutions of different concentrations?
They gain or lose water by osmosis.
What is a common experiment to investigate osmosis in plant tissues?
Placing potato cylinders in solutions of varying sucrose concentrations and measuring their mass or length before and after immersion.
What is a hypotonic solution?
A solution with higher water potential than cell cytoplasm, e.g., pure water.
What occurs when a plant cell is in a hypotonic solution?
Water moves into the cell, making it turgid, and increasing turgor pressure.
What is an isotonic solution?
A solution with the same water potential as cell cytoplasm.
What happens to plant cells in an isotonic solution?
No net water movement occurs, and the cell becomes flaccid.
What is a hypertonic solution?
A solution with lower water potential than cell cytoplasm, e.g., concentrated sugar solution.
What occurs when a plant cell is in a hypertonic solution?
Water moves out of the cell, leading to plasmolysis and making the cell flaccid.
What is the role of water potential in plants?
Water uptake in roots occurs by osmosis, and turgor pressure helps keep plants upright.
What happens to plants when they lose water due to osmosis?
They may wilt.
How does osmosis affect water balance in animal cells?
Osmosis helps maintain water balance in cells.
What happens if animal cells gain too much water?
They may burst (lysis).
What happens if animal cells lose too much water?
They shrink (crenation).
What is active transport?
Movement of molecules or ions across a membrane against their concentration gradient using energy (ATP)
Active transport moves substances from low to high concentration.
Why is active transport important for cells?
It allows cells to absorb essential nutrients, maintains ion balance and homeostasis, and enables functions like nerve impulse transmission and muscle contraction
These functions are critical for cellular health and overall organism function.
Give an example of active transport.
Ion uptake by root hair cells
Root hair cells absorb mineral ions like nitrates from the soil.
How do root hair cells utilize active transport?
They absorb mineral ions from the soil against the concentration gradient
Soil has a lower concentration of these ions than inside the root hair cell.
What energy source is required for active transport?
ATP from respiration
ATP provides the necessary energy to move ions against their concentration gradient.
What role do carrier proteins play in active transport?
They are involved in the movement of molecules across the membrane
Carrier proteins facilitate the transport process.
True or False: Active transport works with the concentration gradient.
False
Active transport works against the concentration gradient.
Fill in the blank: Active transport moves substances from _______ to _______.
low concentration; high concentration
This process requires energy to occur.
What is one function enabled by active transport?
Nerve impulse transmission
This process is essential for communication within the nervous system.
What is the concentration gradient in active transport?
It refers to the difference in concentration of ions or molecules across a membrane
Active transport moves substances from an area of lower concentration to higher concentration.
