scientific method/cell structure Flashcards
Cell membrane
outer boundary of cell
Organelles
structures suspended in cytoplasm
Cytoskeleton
internal scaffolding of protein fibres within cytoplasm
Cell membrane
separates cell contents from outside of cell.
Controls what goes in and out of cell.
Very thin.
cytoplasm
Jelly-like or watery material inside cell that fills all space
cytosol
Liquid part of cytoplasm. 75-90% water Mixture of dissolved substances. compounds suspended in watery fluid. Where most metabolic reactions occur. plays role in osmotic pressure and flow of chemicals in and out of cell.
Organelles
structure within a cell
Nucleus
largest organelle
Nuclear pores to allow large molecules in and out
Stores dna
DNA
Deoxyribonucleic acid
Long strands when cell not splitting
chromosomes when cell is splitting
Nucleolus
manufactures protein inside nucleus
ribosomes
very small, spherical organelles
Amino acids joined together to make proteins
endoplasmic reticulum
Provide surface for chemical reactions
channels for storing or transporting molecules.
Rough when ribosomes
smooth without ribosomes
Golgi apparatus
series of flattened membranes stacked one upon other.
Vesicles formed at the edges.
vesicles
Small sacs of liquid containing proteins
lysosomes
Small sphere bound by membrane. formed from Golgi. Contain digestive enzymes. when liquids/particles enter cell they form vesicles in the cytoplasm, then lysosome join with vesicles and break them down. Digest worn out organelles.
mitochondria
Spherical/sausage shaped.
spread across cytoplasm.
Has double membrane.
smooth outer membrane surrounds mitochondrion.
Inner membrane, cristae, arranged into series of folds extending into interior of organelles.
cellular respiration.
Inner membrane has greater surface area for chemical reactions.
cilia and flagella
To move
Cilia - short, numerous projections
flagella - longer one or two projections
Cytoskeleton
framework of protein fibres that give cell shape and assists cell movement.
Two types: microtubules, microfilaments
Microtubules
hollow rods that keep organelles in place or move them around
microfilaments
Move materials around the cytoplasm or move whole cell
inclusions
Chemical substance not part of cell structure but found in cytoplasms.
Surface area
represents the cells ability to take in enough nutrients and gets rid of waste.
volume
all contents of the cell that needs nutrients and to get rid of waste
Immediate environment
fluid that surrounds it; tissue fluid or extracellular fluid
Extracellular fluid
allows continual exchange of materials in and out of cells.
Homeostasis
body systems work together to ensure cellular environment, kept constant.
Cells maintained at constant temperature, fluids around have constant concentration
fluid mosaic model
Membrane is fluid.
composed of phospholipid molecule, lipid molecules contain phosphate group
Arranged in two layers
phospholipid
Have head and tail.
head is hydrophilic, face outwards
Tail is hydrophobic, face inwards
four types of proteins in membrane
Receptor proteins
channel proteins
Carrier proteins
cell identity marker
Functions of memrane
acts as physical barrier
Regulates passage of materials
sensitive to changes
Helps support the cell
transport through cell
simple diffusion
Facilitated transport
vesicular transport
Simple diffusion
spreading out of molecules so evenly spaced over space available
Concentration gradient
net diffusion
Concentration gradient
greater the difference in concentration, the steeper the diffusion gradient and faster the rate of diffusion
Net diffusion
movement of molecules from higher concentration to lower concentration gradient.
Happens because some molecules move opposite way.
when same amounts molecules move in same direction.
Osmosis
diffusion of solvent through differentially permeable membrane in order to balance concentration of another substance.
Water will osmosis to balance concentration of solutes.
osmotic pressure
The higher the concentration of solute, the higher the osmotic pressure.
facilitated transport
Proteins in membrane allow molecules to be transported across the membrane.
when substances transport along concentration gradient, from higher to lower.
Passive
active transport
Requires energy (ATP)
molecules transported against concentration gradient.
Doesn’t depend on concentration gradient.
vesicular transport
Movement of substances across cell membrane in vesicles.
active
endocytosis
Exocytosis
endocytosis
Taking liquid into cell by vesicular transport
pinocytosis
Phagocytosis
pinocytosis
Take in liquids
Phagocytosis
take in solids
Exocytosis
when contents of vesicle inside cell are passed to the outside
Vesicle fuses wt membrane, contents of vesicle get pushed out into extracellular fluid.
Isotonic
concentration of solute inside cell is same as outside.
Hypertonic
environment outside of cell has higher concentration of solute
Hypotonic
environment outside of cell has higher concentration of solute
