1.2

Question 1

Cell theory states?

Answer 1

all organisms are composed of cells; the cell is the basic
unit of life.

Question 2

Organisms?

Answer 2

can be unicellular, such as amoeba and bacteria, or multicellular such as
plants and animals.

Question 3

How do new cells arise?

Answer 3

from pre-existing cells; specialised cells arise from undifferentiated
stem cells.

Question 4

Eukaryotic cells?

Answer 4

have a nucleus and membrane bound organelles.
Eukaryotic cells include
plant and animal cells.

Question 5

Plant cells?

Answer 5

have additional organelles and structures e.g. chloroplasts for photosynthesis
and cellulose cell walls for support and to maintain turgor pressure.

Question 6

Nucleus?

Answer 6

Contains DNA which codes for or controls protein synthesis.
DNA replication occurs here.
Transcription produces mRNA
templates.

Question 7

Nuclear pores?

Answer 7

Allow the transport of mRNA and ribosomes out of the
nucleus.

Question 8

Nuclear envelope
or double
membrane?

Answer 8

Separates the contents of the nucleus from the cytoplasm.

Question 9

Nucleolus?

Answer 9

Produces rRNA, tRNA and ribosomes

Question 10

Chromatin?

Answer 10

Condenses before cell division to form chromosomes.

Question 11

Rough endoplasmic
reticulum?

Answer 11

Packaging and storing proteins. Producing transport vesicles
which merge to form the Golgi body.

Question 12

Smooth
endoplasmic
reticulum?

Answer 12

Produce, package and transport steroids and lipids.

Question 13

Golgi body/
apparatus?

Answer 13

Packaging proteins for secretion from the cell. Modification
of proteins e.g. by adding carbohydrate chains to form
glycoproteins.
Producing lysosomes and digestive enzymes
(tertiary structure).

Question 14

Lysosomes?

Answer 14

Contain powerful digestive enzymes to break down worn
out organelles or cells. Phagocytes use lysosomes to digest
engulfed bacteria.

Question 15

Centrioles?

Answer 15

Form the spindle during cell division.
They are not present in
higher plant cells.

Question 16

Mitochondria?

Answer 16

ATP synthesis by aerobic respiration.

Question 17

Chloroplasts?

Answer 17

Contain photosynthetic pigments which trap light energy for
photosynthesis.

Question 18

Vacuole?

Answer 18

Contains cell sap and stores solutes such as glucose. Swells
due to osmosis for turgidity

Question 19

Ribosomes?

Answer 19

Protein synthesis. Primary protein structure is formed at the
ribosome.

Question 20

Plasmodesmata?

Answer 20

Connects cells via cytoplasm filled canals, which pass through
cell walls.
Allows transport via the symplastic pathway.

Question 21

Cell wall?

Answer 21

Mechanical strength due to the high tensile strength of
cellulose microfibrils. Transport of solutes via the apoplastic
pathway.
Cell to cell communication via the plasmodesmata

Question 22

Protein synthesis and excretion?

Answer 22

Ribosomes are produced in the nucleolus; they leave the nucleus via the nuclear
pores and take up their positions on the rough endoplasmic reticulum (ER).
The nuclear pores also allow mRNA molecules (formed from DNA templates by
transcription) to leave the nucleus. The mRNA molecules attach to the ribosomes
on the rough ER.
Protein synthesis takes place at the ribosome. The mRNA molecule contains
the code for the primary structure of a protein; the order of amino acids in a
polypeptide chain.
The rough ER transports the polypeptides via transport vesicles, which merge with
the Golgi body.
The polypeptides are modified in the Golgi body and converted to their tertiary
structure e.g. enzymes.
The enzymes are packaged into secretory vesicles and transported to the cell
membrane.
The secretory vesicles merge with the cell membrane and release the enzymes by
exocytosis.

Question 23

Similarities between mitochondria and chloroplast?

Answer 23

Both have double membrane
Both have highly folded inner membranes
Both have a circle of DNA for self-replication
Both have ribosomes
Both produce ATP

Question 24

Differences between them?

Answer 24

Mitochondria have cristae, but chloroplasts have thylakoid membranes.
Chloroplasts contain photosynthetic pigments to absorb light energy, mitochondria
do not.
Mitochondria have an inner matrix, but chloroplasts have a stroma.

Question 25

Bacteria?

Answer 25

Bacteria do not have membrane bound organelles in their cells – no nucleus, rough endoplasmic reticulum, Golgi apparatus, mitochondria or chloroplasts; these cells are prokaryotic cells.

Question 26

Prokaryotic cells?

Answer 26

Small cells Ribosomes smaller and free in cytoplasm No membrane bound organelles DNA = free in cytoplasm no nuclear envelope ( double membrane) plasmids present cell wall = peptidoglycen No mitochondria - uses a mesosome

Question 27

Mesosome?

Answer 27

folded region of the cell membrane for aerobic respiration

Question 28

Eukaryotic cells?

Answer 28

Larger cells 10-100 µm Ribosomes larger and bound to the rough endoplasmic reticulum Membrane bound organelles are present DNA contained within the nucleus Nucleus has a double membrane No plasmids cell wall when present = made of cellulose Mitochondria = used for aerobic respiraition - there is no mesosome

Question 29

Viruses?

Answer 29

do not fit the cell theory have no cell membrane, no cytoplasm, no organelles and no chromosomes can only reproduce with the help of a host cell they are composed of a protein coat or caspd when surrounds DNA RNA or simply a few genes the HIV virus has only 9 genes

Question 30

Atoms to systems?

Answer 30

Atoms = arranged into molecules molecules form cells cells work together to form tissues tissues form organs and organs form systems

Question 31

Tissue defintion?

Answer 31

group of similar cells working together to perform a particular function

Question 32

Epithelial tissue?

Answer 32

type of tissue that forms a continous layer covering or lining external surfaces of the body Epithelia - no blood vessels may have nerve endings cells sit on a basement membrane, made of collagen and protein vary in shape and complexity often have protective or secretory function

Question 33

Cuboidal epithelium?

Answer 33

lines the kidney tubules and the small intestine cube shaped

Question 34

Ciliated epithelium?

Answer 34

composed of cells which transport substances like mucus in the bronchi and ova in the fallopian tube cilia moce and sweep substances along cells = columnar - look like columns

Question 35

Squamous epithelium?

Answer 35

consists of flattened cells on a basement membrane. They form the walls of the alveoli and line Bowman’s capsule in the kidney nephron.

Question 36

Muscle tissue?

Answer 36

comes in 3 main types

Question 37

Skeletal muscle?

Answer 37

attatched to bones and moves skeleton bands of long cells called fibres which contract powerfully but tire easily voluntary muscles - you can choose whether to contract or not Fibres form striped pattern which can be viewed under microscope why they are either referred to as sriped or striated muscle

Question 38

Smooth muscle?

Answer 38

smooth muscle has individual spindle shaped cells that can contract that can contract rhymthically but less powerfully than skeletal muscle Occur in skin but walls of blood vessels and in digestive and respiratory tracts. You cannot control these muscles - involuntary muscles do not have stripes and are also called unstriped or unstriated muscle

Question 39

Cardiac muscle?

Answer 39

is only found in the heart. Its structure and properties are somewhat in between skeletal and smooth muscle. The cells have stripes, but lack the long fibres of skeletal muscle. They contract rhythmically, without any stimulation from nerves or hormones, although these can modify their contraction. Cardiac muscle does not tire.

Question 40

Connective tissue?

Answer 40

connect, support or separate tissues and organs. It contains elastic and collagen fibres in an extracellular fluid or matrix. Between the fibres are fat storing cells (adipocytes) and cells of the immune system.

Question 41

Areolar tissue?

Answer 41

found under the skin and connects organs and tissues together.

Question 42

Collagen?

Answer 42

forms tendons which connect muscles to bones.

Question 43

Ligaments?

Answer 43

which connect bones are elastic tissues.

Question 44

Adipose tissue?

Answer 44

composed of fatty cells and is found justunder the skin and around organs. It functions as an energy store, thermal insulator and protects delicate organs.

Question 45

What are organs comprised of?

Answer 45

several tissues working together, performing a specific function

Question 46

Organ systems?

Answer 46

groups of organs working together with a particular role. Some examples of mammalian organ systems are shown in the table.

Question 47

Calculating true size of structure from a magnified image?

Answer 47

Measure the A to B with a ruler in mm. Divide this by the magnification (this will be given in the question, but is x 50000 in this case). Then multiply by 1000 to convert mm to μm. Remember to give your answer to 3 significant figures.

Question 48

SI?

Answer 48

Système Internationale, the system which defines which units are used for scientific communication

Question 49

Kilometre?

Answer 49

km 0.001 10^3 number of metres Ecosystems

Question 50

Metre?

Answer 50

m 1 1 Larger organisms

Question 51

Millimetre

Answer 51

mm 1000 10^-3 Tissues

Question 52

Micrometre?

Answer 52

µm 1 000 000 10^-6 Cells and organelles

Question 53

Nanometre?

Answer 53

nm 1 000 000 000 10^-9 Molecules

Question 54

Units to remember?

Answer 54

1000nm = 1 µm 1000 µm = 1mm 1000 nm = 1m 1000 m = 1km