biology - unit one Flashcards
what are ciliated epithelium made up of?
goblet and ciliated cells
what is the nucleolus?
the centre of the nucleus responsible for producing ribosomes
what are the two types of filaments in a muscle cell?
- actin - a thin myofilament and appears as a light band (called the I band) under the microscope
- myosin - a thick myofilament and appears as a dark band (called the A band) under the microscope
what is tropomyosin?
a protein filament that prevents the myosin head from attaching to the binding sites on the actin molecule
what is the golgi apparatus?
a compact structure made up cisternae that has a role in modifying proteins and “packing them into vesicles”
what is the vesicle?
membrane sacs that are used to transport materials inside the cell
what does the smooth endoplasmic reticulum do?
synthesises lipids and carbohydrates
what is the role of the rough endoplasmic reticulum ?
synthesises and transports proteins
what are lysosomes?
- a type of vesicle containing hydrolytic enzymes
- breaks down waste material
- digests pathogens ingested by phagocytic cells
what is the first step of the sliding filament theory?
Calcium ions are released from the sarcoplasmic reticulum into the sarcoplasm
what is the second step of the sliding filament theory?
- calcium ions cause tropomyosin to unblock actin-binding sites
-:calcium ions permit cross bridges to form between the actin filament and myosin head
what is the third step of the sliding filament theory?
myosin head uses ATP to pull on thr actin filament towards the line
what is the fourth step of the sliding filament theory?
The sliding of the actin filaments past myosin strands results in the shortening of sarcomeres, translating to the contraction of the muscle
what is the fifth step of the sliding filament theory?
Tropomyosin moves back to block calcium-binding sites when the calcium ions are removed from the sarcoplasm
what is the sixth step of the sliding filament theory?
1) Cross bridges between the actin and myosin are broken.
2) The thin and thick filaments slide away from each other and the sarcomere returns to its original length
what is gram negative bacteria?
- thin peptidoglycan cell walls
- they have an outer lipopolysaccharide membrane
- can’t trap and retain the crystal violet stain, which can be easily washed away by ethanol
- shows up as pink-red under a microscope
what is resolution?
the ability to distinguish between two objects that are close together
what is gram positive bacteria?
- bacteria with thicker peptidoglycan cell walls than gram negative
- they can trap and retain more of a crystal violet stain when it is applied
- appear purple under the microscope
what is magnification?
how many times the image is being enlarged
what are squamous epithelial tissues?
- a lining tissue made from flattened specialised squamous epithelial cells that are one cell thick and form a thin, smooth, flat layer
- used for rapid diffusion
how can epithelium cells be damaged?
- Epithelium cells can be damaged by smoking
- Smoking irritates and causes inflammation and scarring in the epithelium tissue of the lungs
- Alveoli walls become thicker due to scarring and produce more mucus.
what are the impacts of your epithelium cells being damaged?
- loss of natural elasticity
- breathlessness
- persistent coughing
- phlegm
what is ciliated epithelium?
- tissue made up of goblit and ciliated cells with cilia covering the exposed cell surface
- they line the trachea in the respiratory system in order to protect the lungs from infection via sweeping any pathogens away from the lungs
what are goblit cells?
- column shaped
- present in the respiratory tract
- secrete mucus to help trap any unwanted particles that are present in air
- protects the lungs and prevents bacteria reaching the alveoli
what are fast twitch glycolytic muscle fibres?
- muscle fibres that have relatively less myoglobin, few mitochondria and few capillaries
- contains a large concentration of glycogen that provides fuel for anaerobic respiration
- contracts rapidly but also fatigue quickly
what are fast twitch oxidative muscle fibres?
- muscle fibres that contain many mitochondria, myoglobin and blood capillaries
- they are able to hydrolyse ATP much more quickly
- contracts quickly
- relatively resistant to fatigue
what is the function of a sensory neurone?
- transmits impulses from a receptor to either a relay neurone, the brain or
directly to a motor neurone. - has a dendron and an axon on
what is the function of the relay neuron?
- transmits impulses between neurones
- has short axons and dendrons
what is the function of the motor neuron?
- transmit impulses to an effector, from a relay neurone or sensory neurone
- has one long axon and many short dendrites
what are slow twitch muscle fibres?
- more effective at using oxygen to generate energy in the form of ATP
- these fibres help marathon runners and endurance cyclists to continue for hours
what is the nucleus
the part of a cell that contains your DNA
what are ribosomes?
made up of proteins and RNA and are responsible for protein synthesis
what are the two important things that the cell theory states?
- both plant and animal tissue are composed of cells
- cells can only develop from existing cells
what is RNA used for?
producing ribosmal RNA which combine protein to form the ribosomes needed for protein synthesis
where are centrioles only found?
in animal cells
what does the spindle do?
moves chromosomes during cell division
what do centrioles do?
they produce cytoskeleton, which are a network of fibres
what can inhibitory drugs do to synapses?
- they can block the release of neurotransmitters
- they could block the receptors
what can stimulatory drugs do to synapses?
- drugs shaped like neurotransmitters can bind to receptors
- some drugs can stop the neurotransmitters from being broken down
what happens to neurotransmitters at the postynapitc neurone?
they are broken down by enzymes and then are reabsorbed into the synapse
what are amyloplasts?
a double membrane bounded sacresponsible for synthesising and storing starch granules
what are tonoplasts?
the partially permeable membrane of the vacuole that allow small particles to pass through
what are plasmodesmata?
- microscopic channels that cross the plant cell wallls
- they enable transport and communication between individual plant cells
what is a pit?
the pores in the cell walls, allowing water to enter and leave xylem vessels
what are plasmids?
small loops of DNAcarrying genes that may benefit the survival of an organism
what is a capsule?
a slippery layer outside the cell wall that processes the wall and prevents dessication
what is dessication?
what something loses water
what is the nucleoid?
- the irregularily shaped region that holds nuclear material without a nuclear membrane
- where genetic material is located
- controls cellular activity
what is the pilus?
- a hair-like structure associated with bacterial adhesion
- related to bacterial colonization and infection
what do epithelial cells help diffuse?
products of digestion, blood plasma and tissue fluids in and out of blood capillaries
what is myofibril?
fibres made from myofilaments which allow contraction to take place
what is ATP?
an enzyme that transports chemical energy within cells for metabolism
what are sperm cells?
male gametes
what type of tissue forms the lining inside of arteries?
endothelial
what are the pros and cons of light microscopes
PROS:
- cheapaer
- easier to use
- can observe live specimen and specimen colour
CONS:
- lower magnification
- lower resolution
- small sctructures cannot be viewed
what two organelles have a double membrane?
the nucleus and the mitochondrion
why is the heart called an organ?
- an organ is made is up of different tissues like the heart
- the heart pumps blood around the body
why are neurotransmitters reabsorbed?
it allows the resynthesis of nts after they break down
what is endothelium?
a monolayer of endotheliac cells that constitutes the innr cellular lining of the blood vessels and the lymphatic system
what is the name of the technique used to identify gram positive/negative bacteria?
gram staining
what is L-Dopa?
- precursor of Dopamine (1)
- increases the amount of Dopamine {stored in / released by} the presynaptic neuron (1)
- normal levels of dopamine stimulate the postsynaptic neuron
explain how gram negative bacteria prevents penicillin being an effective treatment
- gram-negative bacteria have an outer cell membrane that prevents penicillin from disrupting the cell wall
root hair cell function:
- large surface area = increases the rate of absorption of water and ions from the soil
- thin cell walls for diffusion
- mitochondria = for energy/active transport
- vacuole = for low water potential
why do root hair cells not contain chloroplasts
- there is minimal light in the roots/soil
- photosynthesis cannot take place
what is one structural difference between the rough and smooth ER?
the rough ER has ribosomes attached to its surface
rough ER?
- has ribosomes attached
- responsible for the formation of vesicles
- transports proteins
organ
- a group of tissues
- has vital functions
describe how damage to the alveoli in the lungs leads to emphysema
- emphysema is the destruction of the alveoili
- alveoili walls thicken which then leads to inflammation/swelling
- abnormally larger air spaces in the lungs is formed
- decreased surface area
- reduced gas exchange of oxygen into blood
- alveoili loses elasticity
sperm cell function:
- the acrosome in the head contains enzymes so that a sperm can penetrate an egg
- the head contains the genetic material for fertilisation in ahaploidnucleus
- the middle piece is packed with mitochondria to release energy needed to swim and fertilise the egg
- the tail enables the sperm to swim
egg cell functions:
- one of the largest cells in the human body
- contains a nucleus which houses the genetic material
- the zona pellucida is the outer protective layer/membrane of the egg.
- the corona radiata consists of (two or three layers) and supplies proteins needed by the fertilised egg cell
smooth ER
- flattened cavities surrounded by a thin membrane which do not have anything attached)
- synthesises carbohydrates and lipids
chloroplast
the organelle tthat uses light energy from the sun to make food
what happens to the zona pellucida after the egg cell is fertilised?
the zona pellucida hardens and therefore prevents more than one sperm cell entering the egg cell
