Biology END OF YEAR EXAM Revision Flashcards
Eyepiece
What you look through in a microscope
Stage
The platform where the slide is placed on a microscope
Low power objective lens
Small lens with low magnifying power
High power objective lens
Large lens with high magnifying power
Stage clips
Metal clips that hold a slide securely onto the stage on a microscope
Inclination joint
An adjustable joint that lets the arm tilt at various angles on a microscope
What are the two types of focus wheel on a microscope
Fine focus wheel, coarse focus wheel
Diaphragm (microscope)
An adjustable opening under the stage allowing different amounts of light onto the stage
Two types of microscope
Light microscope, electron microscope
Ribosome function
Make proteins
Cytoplasm is where…
…chemical reactions take place
Nucleus contains…
DNA
Mitochondria is where…
…respiration takes place
Cell membrane function
Controls what goes in and out of the cell
Chloroplast function
Photosynthesis
Cell wall function
Surrounds and protects the cell
Red blood cell function
Carry oxygen around the body
Red blood cell adaptations
Contains haemoglobin, no nucleus, large surface area
White blood cell function
Part of the immune system, fights diseases
White blood cell adaptation
Irregular shape to squeeze through blood vessels
Skin cell function
Creates a barrier between the body and the rest of the world
Skin cell adaptation
Creates keratin
Magnification =
Measured size
——————-
Actual size
Actual size =
Measured size
——————-
Magnification
Features of an animal cell
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
Features of a plant cell
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, cell wall, vacuole
Features of a bacteria cell
Cytoplasm, cell membrane, mitochondria, ribosomes, cell wall, slime capsule, flagella, plasmids, genetic material (not in nucleus), pili
Slime capsule function
Protects bacteria against antibiotics
Flagella function
Helps with movement
Plasmid function
Contains DNA
Pili function
Helps the cell to attach to other things
Catalyst
Speeds up chemical reactions
Enzyme
Biological catalyst
Salivary gland
Produces saliva, contains enzymes
Oesophagus
Carries food from mouth to stomach
Stomach
Churns food
Pancreas
Produces enzymes
Liver
Helps break down fats and old blood cells
Gallbladder
Produces bile
Small Intestine
Absorbs small food particles
Large intestine
Absorbs excess water
Physical digestion
Physically breaking down food eg. Teeth, stomach
Chemical digestion
Breaking down food with enzymes
Enzymes for digesting proteins
Protease
Enzyme for digesting fats and lipids
Lipase
Enzyme for digesting starch
Amalayse
Protease + Protein ——>
Amino Acids
Lipase + Fats/Lipids ——>
Fatty acid + glycerol
Amylase + starch ——>
Glucose
Rate of reaction
Amount of product produced in a certain amount of time
During chemical digestion, if the temperature is increased…
…so will the rate of reaction until optimum temperature is reached
Diffusion
When particles in a high concentration move to an area of low concentration
Osmosis
The diffusion of water molecules through a partially permeable membrane
Active transport
When particles move from an area of low concentration to an area of high concentration, against a concentration gradient. This requires energy.
Order of the stages of mitosis
Prophase, anaphase, metaphase, telophase, cytokinesis
Prophase
Nucleus starts to break down and spindle fibres appear
Metaphase
The chromosomes are lined up on the spindle fibres across the middle of the cell
Anaphase
The chromosome copies are separated and moved to either end of the cell on the spindle fibres
Telophase
A membrane forms around each set of chromosomes to form nuclei
Cytokinesis
Cell surface membrane forms and cell separates
Phase before mitosis
Interphase
Interphase
Diploid cell has two sets of chromosomes, which are copied forming X shapes
Cell formed in mitosis
Daughter cell
Cell at the start of mitosis
Parent cell
Babies are measured in…
Length, mass and head circumference
Babies growth is monitored on…
…percentile curves
25% of babies have a mass below the ??? percentile curve
25th percentile curve
Normal baby grown follows a…
…percentile curve
Animals develop from…
…a single cell
Mitosis results in…
…two identical cells
Cells can ??? to become specialised
Differentiate
Fat cell adaptations
Cytoplasm filled with fat droplets, stores fat until it is needed
Muscle cell adaptations
Has contractile proteins, allows muscles to contract
Nerve cell adaptations
Carries electrical impulses, connects to other neurones
How do cells specialise?
Stem cells divide by mitosis, then elongate and differentiate
Meristems
Tissue in plants containing stem cells, usually in the roots of the plants
Root hair cell adaptations
Large surface area, many tiny hairs, lots of mitochondria
Stem cells in plants features
Divide repeatedly over a long period of time, found in meristems, can differentiate into any cell
Stem cells in animals features
When a fertilised egg cell divides, it contains embryonic stem cell, which can produce any kind of specialised cell. When an animal is fully developed, it can only produce the type of specialised cell in the tissue around it. This is for growth and repair.
Advantages of using stem cells for medical research
Treating diabetes, bone marrow transplants to treat diseases of the blood
Disadvantages of using stem cells for medical research
Can cause cancer, can be killed by the recipients immune system, ethical issues about using stem cells
Uses of stem cells
Treating patients with untreatable conditions, growing organs for transplants, medical research
Homeostasis
The body maintaining balance within its internal environment when faced with external changes
Enzymes will ??? if the temperature is too hot or cold
Denature
The skins role in homeostasis
Controls body temperature with hairs and sweat
The kidneys role in homeostasis
Gets rid of excess water and ions in urine
The pancreas’ role in homeostasis
Keeps body sugar levels constant
The lungs role in homeostasis
Releases excess water and carbon dioxide
Stimuli
Changes in the internal or external environment
Receptor
Cells that detect stimuli
Coordination centres…
…organise messages that come in from receptors
Reflex actions
Automatic actions that do not require thought
Order of the stages of a reflex action
Stimulus —> Receptor —> Sensory Neurone —> Central Nervous System —> Motor Neurone —> Effector —> Response
Electrical impulses ??? across the ??? during a reflex action
Diffuse, synapse
3 main parts of the brain
Cerebrum, cerebellum, medulla oblongata
The cerebrum has two ??? separates by the ???
Hemispheres (left and right), corpus callosum
Corpus callosum role
Hold cerebrum hemispheres together, conducts impulses from one side of the brain to the other
Cerebellum role
Controls movement, muscle tone, posture and balance
Medulla Oblongata
Controls vomiting, coughing, sneezing, swallowing, heat rate, breathing and blood pressure
Retina
Photoreceptive layer of the eye
Optic nerve
Transmits impulses to the brain
Iris
Controls size of the pupil
Cornea
Where the most refraction of light occurs
Lens
Changes it’s shape to focus
Pupil gets ??? In dim light and ??? in bright light
Bigger, smaller
Accommodating
Using the eye to focus light rays onto the retina
Which two places does the light react in our eyes
Cornea then the lens
