Key concepts : cells/transport *

Question 1

How do you calculate the magnification of a microscope?

Answer 1

magnification of microscope = magnification of eyepiece x magnification of objective lens

Question 2

How do you calculate the magnification of an image?

Answer 2

(the I AM triangle)

magnification = image size/ actual size

Question 3

What measurements come after a metre?

How do you go from one measurement to the next?

Answer 3

metre (m) -> millimetre (mm) -> micrometre (μm) -> nanometre (nm)
x 1000 x 1000 x 1000.

Question 4

What is the coverslip on a microscope used for when magnifying a slide?

Answer 4

• protects microscope
• prevents slide from drying out

Question 5

List all the organelles inside an animal cell

Answer 5

• cytoplasm
• cell membrane
• nucleus
• ribosomes
• mitochondria

Question 6

What is cytoplasm?

Answer 6

A jelly-like material that contains dissolved nutrients and salts and organelles.
Where many chemical reactions happen

Question 7

What is the nucleus?

Answer 7

Contains genetic material, including DNA, which controls the cell’s activities

Question 8

What is the cell membrane?

Answer 8

Permeable structure to certain substances that controls the movement of substances in and out of the cell

Question 9

What are mitochondria?

Answer 9

organelles that contain the enzymes for respiration, and where most energy is released in respiration

Question 10

What are ribosomes?

Answer 10

tiny structures where protein synthesis occurs

Question 11

List all the organelles in a plant cell

Answer 11

• cytoplasm
• cell membrane
• cell wall
• nucleus
• mitochondria
• ribosomes
• vacuole
• chloroplasts

Question 12

What are chloroplasts?

Answer 12

organelles that contain chlorophyll, which absorbs light energy for photosynthesis
contains enzymes needed for photosynthesis

Question 13

What is the cell wall?

Answer 13

Made from cellulose fibres and strengthens the cell and supports the plant

Question 14

What is a vacuole?

Answer 14

Filled with cell sap to help keep the cell turgid

Question 15

Which types of cells are prokaryotic?

Answer 15

bacteria cells

Question 16

Which types of cells are eukaryotic?

Answer 16

animal cells and plant cells

Question 17

List all of the organelles in a bacteria cell

Answer 17

• cytoplasm
• cell membrane
• cell wall
• ribosomes
• Plasmid DNA
• chromosomal DNA
• flagellum (not always present)

Question 18

What is a specialised cell?

Answer 18

designed to carry out a particular role, which ensures the organism functions as a whole

Question 19

Give three specialised cells

Answer 19

• 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

Question 20

What is diffusion?

Answer 20

the net movement of particles from an area of high concentration to an area of lower concentration, down a concentration gradient

Question 21

What is a solute?

Answer 21

the dissolved substance in a solution

Question 22

What is a solvent?

Answer 22

the liquid in which a solute dissolves to form a solution

Question 23

What is a solution?

Answer 23

mixture formed by a solute and a solvent

Question 24

Give three factors that can affect the rate of diffusion

Answer 24

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

Question 25

What is osmosis?

Answer 25

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

Question 26

What is a dilute solution?

Answer 26

contains a higher concentration of water molecules

Question 27

What is a concentrated solution?

Answer 27

contains a low concentration of water molecules

Question 28

What does turgid mean?

Answer 28

a cell enlarged and swollen with water

Question 29

What does flaccid mean?

Answer 29

a cell that is soft and floppy

Question 30

What is plasmolysis?

Answer 30

in a very concentrated solution (low water), the cell membrane pulls away from the cell wall completely

Question 31

How do you calculate the change in mass/percentage/concentration etc?

Answer 31

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

Question 32

What is active transport?

Answer 32

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