Movement Into And Out Of Cells Flashcards
What is the small intestine responsible for?
The small intestine absorbs digested food products such as glucose, amino acids, fatty acids, and glycerol.
What is the function of lungs in gas exchange?
Lungs facilitate the exchange of oxygen and carbon dioxide between the alveolar air space and blood in capillaries.
What is diffusion?
Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration.
How do molecules move during diffusion?
Molecules move down a concentration gradient as a result of their random movement.
What is a cell membrane?
The cell membrane is a partially permeable membrane that allows some molecules to cross easily, while others may have difficulty or cannot cross at all.
What is the simplest sort of selection in diffusion based on?
The simplest sort of selection in diffusion is based on the size of the molecules.
How does diffusion help living organisms?
Diffusion helps living organisms obtain many of their requirements, get rid of waste products, and carry out gas exchange for respiration.
What is the effect of surface area to volume ratio on diffusion?
The bigger a cell or structure is, the smaller its surface area to volume ratio is, slowing down the rate at which substances can move across its surface.
How does distance influence the rate of diffusion?
The smaller the distance molecules have to travel, the faster transport will occur.
This is why blood capillaries and alveoli have walls which are only one cell thick, ensuring the rate of diffusion across them is as fast as possible.
What is the relationship between temperature and diffusion?
The higher the temperature, the faster molecules move as they have more energy, resulting in more collisions against the cell membrane and therefore a faster rate of movement across them.
How does concentration gradient affect diffusion?
The greater the difference in concentration on either side of the membrane, the faster movement across it will occur.
This is because on the side with the higher concentration, more random collisions against the membrane will occur.
Why is water important for living organisms?
Water is a solvent, allowing many substances to dissolve in it, making it essential for all life on Earth.
How does water function as a solvent in organisms?
Dissolved substances can be easily transported around organisms, such as in the xylem and phloem of plants and in the blood.
What role does water play in digestion?
Digested food molecules need to be moved to cells throughout the body, which requires water as a solvent.
How does water help in the removal of toxic substances?
Toxic substances like urea and excess salts can dissolve in water, making them easy to remove from the body in urine.
What is the role of water in metabolic reactions?
Water is an important part of the cytoplasm and ensures metabolic reactions can occur as necessary in cells.
What is osmosis?
Osmosis is the diffusion of water molecules from a dilute solution to a more concentrated solution across a partially permeable membrane.
What does it mean for a cell membrane to be partially permeable?
It allows small molecules like water to pass through but not larger molecules like solute molecules.
What is the common practical experiment for osmosis?
Cut cylinders of root vegetables are placed in distilled water and sucrose solutions of increasing concentration.
What happens if plant tissue gains mass in an osmosis experiment?
Water has moved into the plant tissue from the solution, which is more dilute than the plant tissue.
What happens if plant tissue loses mass in an osmosis experiment?
Water has moved out of the plant tissue into the surrounding solution, which is more concentrated than the plant tissue.
What does no overall change in mass indicate in an osmosis experiment?
There has been no net movement of water, meaning the concentration in both the plant tissue and the surrounding solution is equal.
What occurs when water moves into a plant cell?
The vacuole enlarges, pushing the cell membrane against the cell wall, making the cell rigid and firm.
Why is rigidity important for plant cells?
It provides support and strength for the plant, helping it stand upright to catch sunlight.
What prevents plant cells from bursting due to excess water?
The pressure created by the cell wall stops too much water from entering.
What happens to plants when they do not receive enough water?
The cells cannot remain turgid, leading to wilting of the plant.
What is the net movement of water in osmosis?
It moves from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane.
What happens to animal cells in solutions of different concentrations?
Animal cells lose and gain water through osmosis, with more severe effects due to the absence of a cell wall.
What occurs when an animal cell is placed in a strong sugar solution?
It loses water by osmosis and becomes crenated (shrivelled up).
What happens when an animal cell is placed in distilled water?
It gains water by osmosis and may burst if the cell membrane is stretched too far.
What is active transport?
Active transport is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration.
Osmosis
Osmosis experiment
Active Transport
