chapter 1

Question 1

what is the cell theory?

Answer 1

• all living things are made of cells
• cells are the smallest unit of life
• cells can only come from preexisting cells

Question 2

what are all the necessary functions of survival?

Answer 2

metabolism, response, homeostasis, nutrition, excretion, reproduction, growth

Question 3

example of a unicellular organism

Answer 3

paramecium

Question 4

equation to calculate magnification?

Answer 4

magnification = image size / actual size

Question 5

what does the volume of a cell determine?

Answer 5

the level of metabolic activity that takes place

Question 6

what does the surface area of a cell determine?

Answer 6

the rate of exchange of materials

Question 7

what are the advantages of multicellular organisms?

Answer 7

• cells can differentiate so that organisms can grow in complexity

Question 8

why does differentiation increase complexity?

Answer 8

cells can interact with each other

- eg nerve cells and muscle cells react to stimulate movement

Question 9

how does specialist tissue form?

Answer 9

cell differentiation in multicellular

organisms.

Question 10

how do cells differentiate?

Answer 10

different genes are expressed in the cells genome

Question 11

why are stem cells useful for therapeutic treatment?

Answer 11

because they are pluripotent and can differentiate into several types of cell rapidly

Question 12

ethical issues with stem cell treatment?

Answer 12

destruction of a potential child is imoral. if we have a treatment why should it be refused

Question 13

therapeutic uses of stem cells ?

Answer 13

treating leukaemia patients after chemotherapy

Question 14

what is the structure of prokaryotic cells

Answer 14

simple structure without compartmentalization

Question 15

what is the cell wall

Answer 15

surrounds the cell and protects is from bursting

Question 16

what is the plasma membrane

Answer 16

controls the movement of materials into and out of the cell

Question 17

what is a ribosome

Answer 17

where proteins are synthesised

Question 18

what is a flagellum

Answer 18

enables cells to move

Question 19

what is the structure of eukaryotic cells

Answer 19

compartmentalised (contains organelles)

Question 20

what is a rough ER

Answer 20

an ER with ribosomes attached

Question 21

what is a smooth ER

Answer 21

an ER with no ribosomes attached

Question 22

what is golgi apparatus

Answer 22

stacks of flattened membranes responsible for processing proteins made in the rER

Question 23

what are lysosomes

Answer 23

spherical organelle responsible for breaking down components of cells

Question 24

what is the cell membrane made of?

Answer 24

phospholipids, cholesterol, proteins

Question 25

what is the role of cholesterol in the cell membrane

Answer 25

makes membrane less 'fluid', more rigid, and less permeable to water-soluble molecules

Question 26

what are integral proteins?

Answer 26

proteins embedded in the bilayer

Question 27

what are peripheral proteins?

Answer 27

attached to the surface (mainly glycoproteins)

Question 28

who came up with the fluid mosaic model?

Answer 28

singer and nicolson

Question 29

what is passive transport?

Answer 29

the movement of substances down a concentration gradient without the need for energy

Question 30

what is diffusion?

Answer 30

a form of passive transport

Question 31

what is osmosis ?

Answer 31

passive transport where water moves across a partially permeable membrane from high to low concentration

Question 32

what is active transport?

Answer 32

the movement of substances against the concentration the involves energy in the form of ATP

Question 33

what is the role of channel proteins?

Answer 33

channel proteins are required so that water-soluble materials can pass through

Question 34

what is facilitated diffusion?

Answer 34

diffusion across a membrane through specific channel proteins in the membrane without the use of ATP

Question 35

what is water potential?

Answer 35

the tendency of water molecules to move from an area of high concentration to an area of low concentration

Question 36

what is endocytosis?

Answer 36

substances are takes into the cell by indention of the cell membrane requiring ATP

Question 37

what is exocytosis?

Answer 37

substances expelled from the cell requiring ATP

Question 38

how are cells formed?

Answer 38

cells can only be formed by division of preexisting cells

Question 39

what is the endosymbiotic theory?

Answer 39

how eukaryotic cells could have developed from simple or prokaryotic cells

Question 40

what is the evidence for the endosymbiotic theory?

Answer 40

mitochondria and chloroplast contain ribosomes identical to the ones in bacteria, have their own envelope surrounding them and can replicate themselves by binary fission

Question 41

what is a gene?

Answer 41

a length of dna at a specific location on a chromosome that controls a specific heritable characteristic

Question 42

what are the 3 stages of the cell cycle?

Answer 42

interphase, mitosis, cytokinesis

Question 43

what happens in G1?

Answer 43

cell grows, DNA is transcribed, protein is sythesised

Question 44

what happens in the S phase?

Answer 44

DNA is replicated

Question 45

what happens in G2?

Answer 45

cell prepares for devision

Question 46

what happens in mitosis?

Answer 46

cell nucleus divides

Question 47

what happens in cytokinesis?

Answer 47

cytoplasm divides

Question 48

what happens in interphase?

Answer 48

the DNA in the nucleus is replicated, proteins synthesised, no. of mitochondria increase

Question 49

what happens in prophase?

Answer 49

chromosomes become visible and have been drawn into long threads. supercoiling occurs

Question 50

what happens in metaphase?

Answer 50

nuclear envelope is broken down, chromatids align themselves in the middle

Question 51

what happens in anaphase?

Answer 51

centromeres split and sister chromatids are pulled apart, each chromatid is now a chromosome

Question 52

what happens in telophase?

Answer 52

spindle fibres break down and a nuclear envelope forms around each set of chromosomes

Question 53

what is supercoiling?

Answer 53

the condensation of chromosomes

Question 54

what are cyclins?

Answer 54

cyclins are compounds that are involved in the control of the cell cycle

Question 55

what are mutagens?

Answer 55

an agent that causes mutation

Question 56

what is metastasis?

Answer 56

when primary tumours migrate to other tissue and form new secondary tumours

Question 57

what are oncogenes?

Answer 57

a cancer-initiating gene

Question 58

why do oncogenes become active?

Answer 58

mutation in another gene, direct exposure to mutagen and environmental factor eg viral infection