cells + tissues

Play an AI-generated podcast conversation about this lesson

define vesicular transport

Vesicular transport is the movement of substances across the cell membrane in membranous sacs called vesicles. This is an active process, because energy from the cell is needed to form the vesicles.

define endocytosis

Endocytosis is taking liquid or solids into the cell by vesicular transport. The cell membrane folds around a droplet of liquid or a solid particle until the droplet or particle is completely enclosed. The vesicle formed then pinches off and is suspended in the cell’s cytoplasm.

what are the two types of endocytosis

Taking liquids into the cell in this way is called pinocytosis; when the vesicles contain solid particles it is called phagocytosis.

whats exocytosis

Exocytosis is when the contents of a vesicle inside the cell are passed to the outside. A vesicle that is formed inside the cell migrates to the cell membrane and fuses with the membrane. The contents of the vesicle are then pushed out into the extracellular fluid. Signup and view all the answers

why is phospholipid bilayer referred to as fluid mosaic model

luidity: Phospholipids and other molecules move freely within the bilayer, keeping the membrane flexible. Phospholipid Bilayer: The membrane is composed of two layers of phospholipids, with hydrophilic heads facing outward and hydrophobic tails facing inward. Cholesterol: Embedded cholesterol molecules maintain membrane stability and prevent phospholipids from packing too closely. Mosaic Composition: The membrane contains various molecules, including proteins, cholesterol, and phospholipids, creating a "mosaic" pattern. Proteins in the Membrane: Proteins like receptors, channels, and carriers are distributed across or attached to the membrane, supporting various functions. Selective Permeability: The dynamic arrangement controls what substances enter and exit the cell, maintaining internal balance. Signup and view all the answers

what are the four functions of the cell membrane

acts as physical barrier -separates cytoplasm from extracellular fluid around cell regulates passage of materials -controls movement of materials into and out of the cell e.g. entry of ions and nutrients, removal of wastes sensitive to changes -first part of cell affected by any changes in extracellular fluid -has receptors that are sensitive to particular molecules in its surrounding env helps support the cell -internal part of cell membrane attached to microfilaments of cell's cytoskeleton, thus giving support to whole cell -also connections btwn membranes of adjacent cells, providing support to whole tissue Signup and view all the answers

whats carrier mediated transport

passive or active -involves carrier proteins in cell membrane that bind and transport specialised molecules across membrane e.g. potassium and sodium ions against or along with concentration gradient Signup and view all the answers

whats osmosis

the movement of water molecules across a SEMI-PERMEABLE membrane from LOW SOLUTE CONCENTRATION to HIGH SOLUTE CONCENTRATION until equilibrium reached. Signup and view all the answers

epithelial tissue structure and function

tightly packed cells = smooth surface line inside of alimentary canal and outside of lungs and liver **covering/lining tissue Signup and view all the answers

connective tissue structure and function

provide support for body and hold all body parts together -cells are not close together, separated from each other by large amounts matrix e.g. bone, cartilage, blood Signup and view all the answers

muscular tissue structure and function

three types: skeletal: muscle attached to bones voluntary striated smooth: non-striated walls of stomach and intestines, BV involuntary contractions cardiac: myogenic heart muscle involuntary Signup and view all the answers

whats the function of nucleus

control all cellular activities store genetic information produce ribosomes Signup and view all the answers

function of lysosomes

HAS digestive enzymes to break down materials, cellular waste and damaged digestive enzymes digest harmful bacteria and viruses Signup and view all the answers