life @ cellular level - cells & molecules

Question 1

What are stem cells?

Answer 1

Cells that can differentiate into many cells types (multipotent) or any cell type (pluripotent) of the body.

Question 2

what is apoptosis?

Answer 2

Apoptosis is controlled, programmed cell death. It is a normal process

Question 3

What is Necrosis?

Answer 3

Necrosis is the untimely death of cells in response to injury or infection. It is not a normal process.

Question 4

What is cancer?

Answer 4

Cancer is uncontrollable cell division and proliferation which fails to coordinate with normal cells and fails to differentiate into specialized cells.

Question 5

what is a nucleus?

Answer 5

contains DNA, associated with RER

site of ribosomal RNA synthesis and assembly

Question 6

what is the cell membrane?

Answer 6

phosphlipid layer

selectively permeable barrier

embedded proteins act as receptors to detect chemicals and signalling molecules in ECF

Question 7

what is a cytoskeleton?

Answer 7

maintains cell shape

microfilaments - actin (7nm)

intermediate filaments - keratin (8-12nm)

microtubules - tubulin (25nm)

Question 8

what are cilia (supported by cytoskeleton)?

Answer 8

short hair-like projections that move with stiff power stroke and flexible recovery stroke

made of microtubules

Question 9

what are flagella (supported by cytoskeleton)?

Answer 9

long whip-like protein structures that permit snake-like movement

made of 9 pairs of microtubules surrounding a central pair like cilia

Question 10

what are RER and SER?

Answer 10

RER - has ribosomes which synthesis proteins and modifies them

SER - no ribosomes, produces lipids and steroid hormones. Metabolises toxins

Question 11

what is the golgi apparatus?

Answer 11

packages proteins for transport

Question 12

what is mitochondria?

Answer 12

has phospholipid bilayer

outer membrane has pores

inner membrane has cristae (folds)

matrix holds enzymes needed for metabolising food

has own circular DNA and synthesises own ribosomes

can self replicate

Question 13

what are lysosomes?

Answer 13

membrane bound vesicles containing enzymes

used in autophagy (digestion of cells own material) and digestion of engulfed particles

Question 14

what are peroxisomes?

Answer 14

enzymes that degrade long fatty acid chains

generate toxic hydrogen peroxide and breaks it to protect cell

Question 15

what is chemical polarity?

Answer 15

unequal electron distribution
difference in electronegativity (atom’s attraction for the electrons in a bond)

Question 16

what are 2 configurations of carbon molecules?

Answer 16

asymmetrical (chiral)
L- (laevo) - amino acids
D- (dextro) - monosaccharides

symmetrical (achiral)

Question 17

give an example of why configuration is biologically important (rhodopsin)

Answer 17

Rhodopsin is a protein embedded in the retina of the eye.

light exposure causes the configuration of rhodopsin to alter stimulating nerve cells in the optic nerve

send messages to the brain where we see.

Question 18

what is oxidation and reduction?

Answer 18

oxidisation - chemical reaction where electrons are lost, gain of +’ve charge

reduction - chemical reaction where electrons are gained, -
-‘ve charge

Question 18

what is a oxidising and reducing agent?

Answer 18

oxidising agent - becomes reduced itself as it oxidises

reducing agent - becomes oxidies itself as it reduces

Question 19

what is the oxidising and reducing agent in redox reaction of glucose into lactate?

Answer 19

NAD+ is being reduced to NADH (it has gained electrons) thus it is the oxidizing agent, it oxidizes other compounds, takes electrons from them.

NADH is being oxidized to NAD+ (it has lost electrons) thus it is the reducing agent, it reduces other compounds, it gives them electrons.

Question 20

what is a dehydrogenation reaction?

Answer 20

A chemical reaction where hydrogen atoms are transferred from one molecule to another

Question 21

what is a condensation reaction?

Answer 21

A reaction where two smaller molecules combine to form a larger molecules

releases water (or other small molecules e.g. methanol)

Question 22

which of the 5 bases are pyrimidines and purines?

Answer 22

pyrimidines - CTU

purines - AG

Question 22

what is a hydrolysis reaction?

Answer 22

A reaction that adds water to a molecule, and simultaneously breaking down a larger molecule into smaller units

Question 23

what are saturated and unsaturated fatty acids?

Answer 23

saturated - all the bonds are single

unsaturated - there is one double bond

more double bonds = more bendy

Question 23

what are triglycerides?

Answer 23

non-polar storage lipids

composed of 3 fatty acid chains linked to glycerol

Question 24

what are sterols?

Answer 24

produced in plants, animals and some micro-organisms
(cholesterol)

essential component of cell membranes and a precursor to steroid hormones and fat-soluble vitamins
(A, D, E, K)

Question 25

what are phospholipids?

Answer 25

polar lipids that form biological cell membranes

composed of two fatty acid chains and a phosphate group attached to the head of the chains.

Question 26

what are natural killer cells?

Answer 26

lymphocytes which are part of the innate immune system