Cells Chapter 1 and 2 Flashcards

Question

Comparison of plant and animal cells

Answer 1

Plant and animal cells have common organelles Plants have both mitochondria and chloroplasts and therefore can undergo cellular respiration and photosynthesis Plants have a cell wall that aids with structural support but animal cells do not Plant cells also have a permanent large vacuole for the storage of water, minerals and ions. Animal cells have small vacuoles that may not be permanent

Answer 2

Keep foreign molecules out Exchange substances with the external environment Without this boundary cells cannot survive and life wouldn’t exist It selectively controls the entry and exit of materials – SEMIPERMEABLE

Answer 3

Phospholipid bilayer Proteins embedded within and on surface Hydrophilic – water-loving heads to the outside Hydrophobic – water-hating tails on the inside Having these properties allows the membrane to select what can enter and leave the cell

Answer 4

Outermost layer in PLANTS, FUNGI and BACTERIA Provides support and protection Has no selective properties Plants: Made of CELLULOSE (complex carbohydrate) Fungi: Made of CHITIN (polysaccharide) Bacteria: Made of long strands of POLYSACCHARIDES and AMINO ACIDS

Answer 5

The hydrophilic heads are exposed at BOTH external environments The hydrophobic tails face each other Lipophilic/hydrophobic substances move freely through the phospholipid bilayer due to the hydrophobic nature of fatty acid tails Water, gases and other small hydrophobic and polar molecules can diffuse directly The plasma membrane is selective

Answer 6

There are 4 main types of transport Some are passive and some are active

Answer 7

Movement of substances across the phospholipid bilayer from a region of higher concentration to one of lower concentration Going down the concentration gradient NO ENERGY When both sides are equal in concentration, diffusion stops Small lipophilic substances move across easily

Answer 8

Going down the concentration gradient means substances will move from higher concentration to lower It will stop moving until both sides are equal

Answer 9

Enables molecules that cannot diffuse across the phospholipid bilayer to move across it by transporter proteins NO ENERGY can be carrier proteins or channel proteins Carrier proteins undergo structural changes when binding to a molecule and deliver it to the other side of the membrane

Answer 10

Moves dissolved substances from a region of LOW concentration to HIGH (against the concentration gradient) REQUIRE ENERGY (ATP)

Answer 11

ENDO: solid particles taken INTO a cell EXO: solid particles taken OUT of a cell Bulk transport A vesicle is formed using the membrane PHAGOCYTOSIS: solid material PINOCYTOSIS: fluid material

Answer 12

1) Active and selective boundary Separating cell from the external environment, allows passage of SOME substances Active boundaries around organelles that help it maintain internal environments different from the cytosol 2) Denotes cell identity Glycoproteins on the outside of the membrane act as cell markers Each cell type has its own marker to help distinguish between self and foreign cells 3) Receives external signals Can be a hormone Receptors on the outside of the membrane allows signals to bind to it The cell can then carry out a response 4) Transports material Allows some substances to cross directly through the phospholipid bilayer Some need to go through protein

Answer 13

Net movement of water across a semipermeable membrane from a solution of high water concentration to one of lower concentration ‘ HYPOtonic: lower solute concentration ISOTONIC: equal solute concentration HYPERtonic: higher solute concentration

Answer 14

That the concentration of solutes dissolved in an extracellular solution can determine the direction and rate of osmosis