cells

Question 1

what organelles do prokaryotic cells lack and give an example of a prokaryotic cell

Answer 1

Bacteria cell
no nuclear membrane
no mitochondria
no membrane bound organelles

Question 2

what are stem cells

Answer 2

cells that can differentiate into many (multipotent) or any (pluripotent) cell types

Question 3

during cell differentiation, why do daughter cells develop into different cell types

Answer 3

due to the differences in gene expression and the local cellular environment

Question 4

what is apoptosis

Answer 4

controlled, programmed cell death. It’s a normal process

Question 5

what do you can the process when cells die in response to injury or infection

Answer 5

Necrosis- not a normal process

Question 6

what do proteins in the cell membrane act as and what do these detect

Answer 6

receptors-to detect chemical messengers and signalling molecules in the fluid surrounding cells

Question 7

what are nucleoli

Answer 7

sites or ribosomal RNA synthesis and ribosomal assembly

Question 8

what the difference between rough ER and smooth ER

Answer 8

rough has ribosomes attached which synthesis proteins

Question 9

what is the function of the RER and SER

Answer 9

RER- protein synthesis by the ribosomes, and modifies proteins
SER- lipid and steroid hormone production and metabolism of toxins

Question 10

what is the function of the golgi apparatus

Answer 10

packages up proteins in preparation for transport out of the cell

Question 11

what are cristae

Answer 11

folds in the inner membrane of the mitochondria which increase surface area

Question 12

what does the matrix in the mitochondria hold

Answer 12

most of the enzymes required for metabolising food molecules

Question 13

what are lysosomes and what are their function

Answer 13

membrane bound vesicles containing enzymes and they separate enzymes from rest of the cell

Question 14

what is the function of the cytoskeleton

Answer 14

supports and maintains cell shape, holds organelles in position and helps move organelles around the cell

Question 15

what 3 forms of protein make up the cytoskeleton

Answer 15

1. microfilaments
2. Intermediate Filaments
3. Microtubules

Question 16

name 2 examples of cells that are made of microtubules and describe each

Answer 16

cilia- short, many present, move with stiff power stroke and flexible recovery stroke
flagella- longer, usually 1 or 2 present, movement is snakelike

Question 17

why is it important to not disrupt the apoptotic process

Answer 17

as disruption is associated with some cancers

Question 18

what is carbon describes as and why

Answer 18

versatile- as it can form stable bonds with H, O and N. This versatility explains why it forms the basis of almost all biomolecules

Question 19

what is the definition of configuration

Answer 19

the fixed arrangement of atoms in a molecule

Question 20

name the 2 distinct configurations that biomolecules containing c=c can have

Answer 20

trans- wonky tick shape?

cis- half a hexagon shape

Question 21

What do you call molecules that are asymmetric and symmetrical

Answer 21

asymmetric= chiral
symmetrical= achiral

Question 22

what are chiral molecules describes as being-

Answer 22

L- (Laevo
D- (Dextro)
these exert different biological effects

Question 23

List the 5 types of chemical reactions

Answer 23

1. Redox reaction
2. Making/breaking c-c bond
3. internal rearrangements
4. Group transfer
5. Condensation/ hydrolysis

Question 24

NADH and NAD+ are what type of agents

Answer 24

NADH- reducing agent

NAD+ - oxidising agent

Question 25

what is a condensation reaction

Answer 25

when 2 smaller molecules combine to form a larger molecule and doing so release water (or other small molecules)

Question 26

what is a hydrolysis reaction

Answer 26

when a larger molecule is broken down into 2 smaller molecules, using water to do so.

Question 27

the sub units of what 3 molecules are joined and broken by condensation and hydrolysis reactions

Answer 27

proteins polysaccharides nucleic acids

Question 28

what is cyclic form

Answer 28

the form that monomers are locked in when they link together

Question 29

what does the end monomer in a cyclic form, form?

Answer 29

a reducing end and it remains linear

Question 30

the linear form in a monomer chain has contains what type of group and what does this allow

Answer 30

contains an aldehyde group- which can be oxidised. If it's oxidised another reactant would be reduced so glucose is termed a 'reducing sugar'

Question 31

name the 2 kinds of base in nucleic acids and give examples

Answer 31

pyrimidines- C, T, U | Purines- A, G

Question 32

state 3 differences between RNA and DNA

Answer 32

1. DNA has deoxyribose sugar, RNA has ribose 2. DNA is double stranded, RNA is single stranded 3. DNA has the base Thymine, RNA has the base Uracil

Question 33

what makes a fatty acid molecule more fluid

Answer 33

the more unsaturated (double bonds) the fatty acid chain has, the more fluid it is.

Question 34

state what a lipid is and name the 3 classes of them

Answer 34

a lipid is a family of molecules made up of fatty acids 1. triglycerides 2. phospholipids 2. sterols

Question 35

whats the difference between triacylglycerides and phospholipids

Answer 35

triglycerides have 3 fatty acid chains linked to glycerol and phospholipids have 2 fatty acid chains and a phosphate head

Question 36

what type of lipid forms biological cell membranes

Answer 36

phospholipids!!

Question 37

whats the most important sterol in humans

Answer 37

cholesterol

Question 38

water is polar- what does this mean

Answer 38

the charge within the water molecule is not distributed evenly giving it a slightly +ve charge at the H end and a slight -ve charge at the O end

Question 39

in what shape of molecule are hydrogen bonds strongest and why is this of biological importance

Answer 39

when the 3 atoms involved lie in a straight line. Of biologically importance because it determines the very precise 3D structures of lots of molecules such as proteins and DNA

Question 40

what is the hydrophobic effect

Answer 40

when hydrophobic molecules eg. lipids, cluster together to minimise contact with surrounding water molecules and minimise disruption of H bonding

Question 41

what do you call a molecule that contains both hydrophobic and hydrophilic parts and give an example of a molecule

Answer 41

amphipathic | phospholipids example

Question 42

how to phospholipids minimise disruption of their H bonds

Answer 42

form micelles or bilayers so that the hydrophobic tail is facing inwards and protected form water contact

Question 43

what is a liposome

Answer 43

a sphere made up of lots of phospholipids that has a lipid bilayer outer shell and a hollow core

Question 44

whats the difference between a micelle and a liposome

Answer 44

a micelle has no core and a liposome has a hollow core | micelle has a single layer of phospholipids

Question 45

what is a chylomicron

Answer 45

its like a liposome with protein embedded in the shell and lipid store in the core

Question 46

what is the purpose of the hydrophilic shell on a chylomicron

Answer 46

to allow the chylomicron to be transported in the aqueous plasma of the blood

Question 47

how does oxygen and carbon dioxide travel in blood plasma

Answer 47

oxygen- in haemoglobin in red blood cells | co2- forms bicarbonate ions in the presence of water

Question 48

whats the difference between a strong and weak acids/bases

Answer 48

strong acids/bases are fully dissociated when dissolved in water weak acids/bases are only partially dissociated when dissolved in water

Question 49

name the buffer systems used in cells and plasma

Answer 49

cells- phosphate | plasma- bicarbonate

Question 50

when you add more buffer and more H buffer, what effect do these have on PH

Answer 50

buffer- PH increases, becomes more alkaline | H Buffer- PH decreases, becomes more acidic