cells Flashcards
what organelles do prokaryotic cells lack and give an example of a prokaryotic cell
Bacteria cell
no nuclear membrane
no mitochondria
no membrane bound organelles
what are stem cells
cells that can differentiate into many (multipotent) or any (pluripotent) cell types
during cell differentiation, why do daughter cells develop into different cell types
due to the differences in gene expression and the local cellular environment
what is apoptosis
controlled, programmed cell death. It’s a normal process
what do you can the process when cells die in response to injury or infection
Necrosis- not a normal process
what do proteins in the cell membrane act as and what do these detect
receptors-to detect chemical messengers and signalling molecules in the fluid surrounding cells
what are nucleoli
sites or ribosomal RNA synthesis and ribosomal assembly
what the difference between rough ER and smooth ER
rough has ribosomes attached which synthesis proteins
what is the function of the RER and SER
RER- protein synthesis by the ribosomes, and modifies proteins
SER- lipid and steroid hormone production and metabolism of toxins
what is the function of the golgi apparatus
packages up proteins in preparation for transport out of the cell
what are cristae
folds in the inner membrane of the mitochondria which increase surface area
what does the matrix in the mitochondria hold
most of the enzymes required for metabolising food molecules
what are lysosomes and what are their function
membrane bound vesicles containing enzymes and they separate enzymes from rest of the cell
what is the function of the cytoskeleton
supports and maintains cell shape, holds organelles in position and helps move organelles around the cell
what 3 forms of protein make up the cytoskeleton
- microfilaments
- Intermediate Filaments
- Microtubules
name 2 examples of cells that are made of microtubules and describe each
cilia- short, many present, move with stiff power stroke and flexible recovery stroke
flagella- longer, usually 1 or 2 present, movement is snakelike
why is it important to not disrupt the apoptotic process
as disruption is associated with some cancers
what is carbon describes as and why
versatile- as it can form stable bonds with H, O and N. This versatility explains why it forms the basis of almost all biomolecules
what is the definition of configuration
the fixed arrangement of atoms in a molecule
name the 2 distinct configurations that biomolecules containing c=c can have
trans- wonky tick shape?
cis- half a hexagon shape
What do you call molecules that are asymmetric and symmetrical
asymmetric= chiral symmetrical= achiral
what are chiral molecules describes as being-
L- (Laevo
D- (Dextro)
these exert different biological effects
List the 5 types of chemical reactions
- Redox reaction
- Making/breaking c-c bond
- internal rearrangements
- Group transfer
- Condensation/ hydrolysis
NADH and NAD+ are what type of agents
NADH- reducing agent
NAD+ - oxidising agent
what is a condensation reaction
when 2 smaller molecules combine to form a larger molecule and doing so release water (or other small molecules)
what is a hydrolysis reaction
when a larger molecule is broken down into 2 smaller molecules, using water to do so.
the sub units of what 3 molecules are joined and broken by condensation and hydrolysis reactions
proteins
polysaccharides
nucleic acids
what is cyclic form
the form that monomers are locked in when they link together
what does the end monomer in a cyclic form, form?
a reducing end and it remains linear
the linear form in a monomer chain has contains what type of group and what does this allow
contains an aldehyde group- which can be oxidised. If it’s oxidised another reactant would be reduced so glucose is termed a ‘reducing sugar’
name the 2 kinds of base in nucleic acids and give examples
pyrimidines- C, T, U
Purines- A, G
state 3 differences between RNA and DNA
- DNA has deoxyribose sugar, RNA has ribose
- DNA is double stranded, RNA is single stranded
- DNA has the base Thymine, RNA has the base Uracil
what makes a fatty acid molecule more fluid
the more unsaturated (double bonds) the fatty acid chain has, the more fluid it is.
state what a lipid is and name the 3 classes of them
a lipid is a family of molecules made up of fatty acids
- triglycerides
- phospholipids
- sterols
whats the difference between triacylglycerides and phospholipids
triglycerides have 3 fatty acid chains linked to glycerol and phospholipids have 2 fatty acid chains and a phosphate head
what type of lipid forms biological cell membranes
phospholipids!!
whats the most important sterol in humans
cholesterol
water is polar- what does this mean
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
in what shape of molecule are hydrogen bonds strongest and why is this of biological importance
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
what is the hydrophobic effect
when hydrophobic molecules eg. lipids, cluster together to minimise contact with surrounding water molecules and minimise disruption of H bonding
what do you call a molecule that contains both hydrophobic and hydrophilic parts and give an example of a molecule
amphipathic
phospholipids example
how to phospholipids minimise disruption of their H bonds
form micelles or bilayers so that the hydrophobic tail is facing inwards and protected form water contact
what is a liposome
a sphere made up of lots of phospholipids that has a lipid bilayer outer shell and a hollow core
whats the difference between a micelle and a liposome
a micelle has no core and a liposome has a hollow core
micelle has a single layer of phospholipids
what is a chylomicron
its like a liposome with protein embedded in the shell and lipid store in the core
what is the purpose of the hydrophilic shell on a chylomicron
to allow the chylomicron to be transported in the aqueous plasma of the blood
how does oxygen and carbon dioxide travel in blood plasma
oxygen- in haemoglobin in red blood cells
co2- forms bicarbonate ions in the presence of water
whats the difference between a strong and weak acids/bases
strong acids/bases are fully dissociated when dissolved in water
weak acids/bases are only partially dissociated when dissolved in water
name the buffer systems used in cells and plasma
cells- phosphate
plasma- bicarbonate
when you add more buffer and more H buffer, what effect do these have on PH
buffer- PH increases, becomes more alkaline
H Buffer- PH decreases, becomes more acidic
