Key Concepts

Question 1

Eukaryotic

Answer 1

• complex cells
• include all animal and plant cells
• make eukaryotes

Question 2

Prokaryotic

Answer 2

• small and simple
• make a prokaryote (single cell organism) from one prokaryotic cells

Question 3

Nucleus

Answer 3

• plants and animals
• contains genetic material which controls the activities of the cell
• genetic material is arranged in chromosomes

Question 4

Cytoplasm

Answer 4

• plant and animal
• gel-like substance where most chemical reactions happen
• contains enzymes which control the chemical reactions

Question 5

Cell Membrane

Answer 5

• plant and animal cells
• holds the cell together
• controls what goes in and out of the cell

Question 6

Mitochondria

Answer 6

• plant and animal cells
• where most of the reactions for respiration take place

Question 7

Ribosomes

Answer 7

• plant and animal cells
• involved in the translation of genetic material in the synthesis of protiens

Question 8

Cell Wall

Answer 8

• plant cells
• made from cellulose
• supports and strengthens the cell

Question 9

Vacuole

Answer 9

• plant cells
• contains cell sap (weak solution of sugar and salts)
• maintains the internal pressure of the cell for support

Question 10

Chloroplasts

Answer 10

• plant cells
• where photosynthesis occurs
• contain chlorophyll

Question 11

Chromosomal DNA

Answer 11

• bacterial cells
• one long circular chromosome
• controls cell activities and replication
• floats free in cytoplasm

Question 12

Plasmid DNA

Answer 12

• bacterial cell
• small loops of extra DNA
• are not a part of the chromosome
• contain genes for drug resistance
• can be passed between bacteria

Question 13

Flagellum

Answer 13

• bacterial cells
• long, hair-like structure which allows the cell to move

Question 14

Specialised Cells

Answer 14

• cells which are adapted to a specific function

Question 15

Sexual Reproduction

Answer 15

The nucleus of an egg and sperm cell fuse to create a fertilised egg which develops into an embryo

Question 16

Egg Cell Adaptions

Answer 16

• haploid cell to ensure a diploid cell at fertilisation
• carries female DNA
• nourish the developing embryo (contains nutrients in the cytoplasm)
• membrane changes structure after fertilisation to prevent anymore sperm entering

Question 17

Sperm Cell Adaptations

Answer 17

• haploid to ensure diploid cell at fertilisation
• contains male DNA
• transportation of male DNA to female egg
• long tail for movement
• mitochondria in middle section for energy for swimming
• acrosome which stores enzymes to digest membrane of egg cell

Question 18

Ciliated Epithelial Cell Adaptations

Answer 18

• line the surface of organs
• to move substances in one direction along the surface of the tissue

Question 19

Microscopes

Answer 19

• use lenses to magnify images
• can increase resolution of an image

Question 20

Resolution

Answer 20

how well a microscope distinguishes between two points that are close together

Question 21

Light Microscopes

Answer 21

• passing light through a specimen
• can see nuclei and chloroplasts
• allow the study of living cells

Question 22

Electron Microscopes

Answer 22

• use electrons not light
• higher magnification and resolution
• can see smaller images
• cannot be used to view living cells

Question 23

Making a Specimen

Answer 23

1. Thin slice of a specimen using a scapel
2. Clean slide with a drop of water in the middle
3. Place specimen on slide with tweezers
4. Add a drop of stain to specimen (methylene blue for DNA)
5. Place cover slip slowly over specimen

Question 24

Using a Microscope

Answer 24

1. Clip slide onto the stage
2. Select the lowest objective lens
3. Use coarse adjustment knob to move the stage
4. Adjust the focus with the fine adjustment knob until there is a clear image

Question 25

Total Magnification =

Answer 25

Eyepiece lens magnification * Objective lens magnification

Question 26

Magnification =

Answer 26

Image Size/ Actual Size

Question 27

Enzymes

Answer 27

• biological catalyst
• increase the speed of a reaction without being changed or used up

Question 28

Enzyme Reactions, Lock and Key

Answer 28

• The substrate fits in the active site
• Enzyme catalyses reaction
• Product is formed

Question 29

Enzymes, Rate of Reaction

Answer 29

• Temperature:
  > high temperatures increase rate at first
  > when it is too hot, bonds holding the enzyme together break, denaturing
  > all enzymes have an optimum temperature
• pH:
  > too high or too low will cause interference with bonds and denaturing
  > all enzymes have an optimum pH
• Concentration:
  > the higher the concentration of substrate/ enzyme, faster reaction
  > limiting factor