Key concepts : cells/transport * Flashcards
How do you calculate the magnification of a microscope?
magnification of microscope = magnification of eyepiece x magnification of objective lens
How do you calculate the magnification of an image?
(the I AM triangle)
magnification = image size/ actual size
What measurements come after a metre?
How do you go from one measurement to the next?
metre (m) -> millimetre (mm) -> micrometre (μm) -> nanometre (nm)
x 1000 x 1000 x 1000.
What is the coverslip on a microscope used for when magnifying a slide?
- protects microscope
- prevents slide from drying out
List all the organelles inside an animal cell
- cytoplasm
- cell membrane
- nucleus
- ribosomes
- mitochondria
What is cytoplasm?
A jelly-like material that contains dissolved nutrients and salts and organelles.
Where many chemical reactions happen
What is the nucleus?
Contains genetic material, including DNA, which controls the cell’s activities
What is the cell membrane?
Permeable structure to certain substances that controls the movement of substances in and out of the cell
What are mitochondria?
organelles that contain the enzymes for respiration, and where most energy is released in respiration
What are ribosomes?
tiny structures where protein synthesis occurs
List all the organelles in a plant cell
- cytoplasm
- cell membrane
- cell wall
- nucleus
- mitochondria
- ribosomes
- vacuole
- chloroplasts
What are chloroplasts?
organelles that contain chlorophyll, which absorbs light energy for photosynthesis
contains enzymes needed for photosynthesis
What is the cell wall?
Made from cellulose fibres and strengthens the cell and supports the plant
What is a vacuole?
Filled with cell sap to help keep the cell turgid
Which types of cells are prokaryotic?
bacteria cells
Which types of cells are eukaryotic?
animal cells and plant cells
List all of the organelles in a bacteria cell
- cytoplasm
- cell membrane
- cell wall
- ribosomes
- Plasmid DNA
- chromosomal DNA
- flagellum (not always present)
What is a specialised cell?
designed to carry out a particular role, which ensures the organism functions as a whole
Give three specialised cells
- sperm cell : head contains a haploid nucleus, and the acrosome contains an enzyme that allows it to penetrate the egg, middle piece contains lots of mitochondria to release energy and tail enables sperm to swim.
- red blood cell : doesn’t contain a nucleus to give more space for oxygen, has an indented shape so that is has a higher surface area, to enable more oxygen to diffuse into it quicker
- root hair cell : has a large surface area so that more water can travel into the cell (through active transport), has thin walls so as to not restrict the movement of water
What is diffusion?
the net movement of particles from an area of high concentration to an area of lower concentration, down a concentration gradient
What is a solute?
the dissolved substance in a solution
What is a solvent?
the liquid in which a solute dissolves to form a solution
What is a solution?
mixture formed by a solute and a solvent
Give three factors that can affect the rate of diffusion
concentration gradient : the greater the difference in concentration, the quicker the rate of diffusion
temperature : the higher the temperature, the more kinetic energy the particles have, so they move and mix quicker
surface area of cell membrane separating regions : the greater the surface area, the faster the rate of diffusion
What is osmosis?
the net movement of water particles from an area of high water concentration to an area of low water concentration through a partially permeable membrane, down a concentration gradient
What is a dilute solution?
contains a higher concentration of water molecules
What is a concentrated solution?
contains a low concentration of water molecules
What does turgid mean?
a cell enlarged and swollen with water
What does flaccid mean?
a cell that is soft and floppy
What is plasmolysis?
in a very concentrated solution (low water), the cell membrane pulls away from the cell wall completely
How do you calculate the change in mass/percentage/concentration etc?
eg. mass
change in mass = mass at end - mass at start
eg. percentage change
change in percentage = current percentage - old percentage / current percentage x 100
What is active transport?
the net movement of particles from an area of low concentration to an area of high concentration, up/against a concentration gradient using energy from resperation
