Biology unit 1 Flashcards
photosynthesis equation
carbon dioxide + water → glucose + oxygen
what do food chains show?
These diagrams illustrate the movement of food ENERGY from one organism to an other.
use of protein in the body
growth and repair of muscles and tissues
use of carbohydrates in the body
main source of energy
use of fats in the body
secondary source of energy, insulate the body
use of fibre in the body
regulate use of sugar, helps move food through the body and prevent constipation
what are the two main cycles in nature
the carbon and nitrogen cycle
how to test for the presence of starch
iodine solution
how to test for the presence of glucose
Benedict’s reagent
how to test for the presence of protein
Biuret solution
what is digestion
Digestion is the conversion of large, insoluble food molecules into smaller soluble molecules so they can be absorbed into the blood for use by body cells.
what is an enzyme
Enzymes (made of proteins) are biological catalysts that speed up chemical reactions
what is the enzyme used to breakup carbohydrates + example
carbohydrase enzymes such as salivary amylase
what is the enzyme used to breakup lipids + example
lipase enzymes such as pancreatic lipase
what is the enzyme used to breakup proteins + example
protease enzymes such as pepsin
what are carbohydrates broken down into
glucose molecules
what are proteins broken down into
amino acid molecules
what are lipids broken down into
fatty acids and glycerol molecules
function of the mouth
Site of ingestion.
Teeth chew food - increases the surface area for enzymes to act.
Saliva produced in the salivary glands. Saliva helps moisten and lubricate food.
Chemical digestion of carbohydrates using carbohydrase enzyme (salivary amylase).
function of the stomach
Acid kills any bacteria
Start the chemical digestion of proteins into amino acids.
function of the pancreas
The pancreas is responsible for producing the digestive enzymes: Carbohydrase, Proteases and Lipases.
function of the small intestine
Completes the process of digestion.
Carbohydrase enzymes digest Starch - Glucose
Protease enzymes digest proteins - Amino acids
Lipase enzymes digest lipids - Fatty acids and Glycerol
Absorption - all of the useful small and soluble nutrients are absorbed into the bloodstream.
function of the large intestine
The absorption of water and vitamins into the bloodstream.
function of the liver
produces bile that is stored in the gall bladder
Synthesis of plasma proteins
Storage of glycogen, vitamins, and minerals.
what is peristalsis
This contraction and relaxation of muscles moves food along your gut from mouth to anus.
what is diffusion
molecules passing from a high concentration to a low concentration.
By which process do the useful food molecules pass into the capillaries?
diffusion
What is the main adaptation of the villi in the small intestines’ for the process of absorption?
Increases the surface area for absorption of food nutrients into the blood.
What role do the blood vessels have in the process of absorption?
Takes all the useful food nutrients away to the body cells.
Maintains the concentration gradient.
Visking tubing can be used as a model gut. What are the limitations of the model?
No surface area - no villi
no blood stream to take away the nutrients
what is the word equation for respiration
GLUCOSE + OXYGEN —-> ENERGY + CARBON DIOXIDE + WATER
what is cell theory?
‘All living things are made up of cells or cell products’
what is found in the chromosomes?
DNA
what provides the energy for photosynthesis
the sun
what is the function of the nucleus?
controls the activities of the cell and contains the genetic information in chromosomes (DNA)
what is the function of the cytoplasm?
it is the site of chemical reactions
what is the function of the cell wall?
it provides shape, support and structure to a cell
how do plants trap light energy needed for photosynthesis
energy is trapped by the chlorophyll
what is the function of the chloroplasts?
it is the site of photosynthesis
what is the function of the cell membrane?
It controls which substances enters and leaves the cell
why do most plants appear green in colour
because of the large amount of chlorophyll
What is the function of the vacuole?
It contains water
What is the function of the mitochondria?
It is the site of aerobic respiration
where is chlorophyll found in a plant
in the chloroplasts
what is the process called by which energy is released from glucose?
Respiration
Which features do plant cells have?
- Nucleus
- Chloroplast
- Cytoplasm
- Cell membrane
- Cell wall
- Vacuole
- Chromosomes
- Mitochondria
what do plants use glucose created in photosynthesis for
some of the glucose is used immediately for respiration but most of it is stored as starch or used to make other chemicals like cellulose.
as a result of photosynthesis, light energy from the sun is converted into _______ energy
chemical
Which features do animal cells have?
- Nucleus
- Cytoplasm
- Cell membrane
- Chromosomes
- Mitochondria
Which features do both plant and animal cells have?
- Nucleus
- Cytoplasm
- Cell membrane
- Chromosomes
- Mitochondria
which part of a plant contains cellulose?
cell membrane
what is an enzyme
a biological catalyst
How do you calculate the total magnification?
magnifying power x magnifying piece
of eyepiece lens of objective lens
how is glucose used by a plant
used for respiration and to make other chemicals like proteins and oils
what chemical is used to test for starch
iodine
what are the advantages of a light microscope?
- can be used on live specimen
- cheap and easy to use
what are the disadvantages of a light microscope?
- can only magnify up to 1000 times
what is the function of red blood cells
carries oxygen around the body
what are the advantages of an electron microscope?
- can magnify up to 50,000 times.
- much more detail visible
what are the disadvantages of an electron microscope?
- Can only observe dead tissue
- very expensive
- big and complex
what is the function of white blood cells
defence against disease
what do phagocytes do
engulf and digest pathogens
where are phagocytes found
in white blood cells
what is osmosis
Osmosis is the diffusion of water molecules from an area of high water concentration to an area of low water concentration through a selectively permeable membrane.
what is a selectively permeable membrane
a ‘wall’ that lets some molecules through but not others e.g a cell membrane
what is a concentrated solution
has a high solute concentration and therefore a low water concentration
what is a dilute solution
has a low solute concentration and therefore a high water concentration
name two examples of solute molecules
salts
sugars
what is the purpose of pores in a selectively permeable membrane
The pores in the membrane allow small water molecules to pass through.
what are tissues
Groups of similar cells with a
similar function.
what is an organ
Several tissues performing specific
functions.
what is an organ system
A number of organs working together to carry
out specific functions.
name an example of an organ system
the circulatory system
what 3 factors can affect the rate of diffusion
concentration
temperature
pressure
how is a visking tube similar to a cell membrane
it also has a selectively permeable membrane.
It has tiny holes (pores), which allow small molecules through, but stop molecules that are too large to fit through them.
what is active transport
When the concentration of a material is lower outside the cell it must be actively transported into the cell
name 3 examples of active transport
Nitrate ions must be actively transported from the soil water to the inside of the plant cells
Glucose actively transported from the small intestine into the blood.
Marine algae can use active transport to concentrate iodine in their cells
what is an enzyme
an enzyme is a biological catalyst; it speeds up a reaction, but it does not
take part in the reaction.
how do enzymes work
The way enzymes work is
described by the lock and key
model.
why is a substrate held in the active site of an enzyme
to increase the probability that a
reaction will take place.
when do enzymes work best
- at the optimum pH
- at the right temperature
- with the right molecule (they can only catalyze one type of molecule)
what is denaturation
when an enzyme’s active site changes shape due to a change in conditions and stops working
what form of energy is released in respiration
ATP molecules
what is aerobic respiration
when food glucose is converted into energy in the presence of oxygen.
what are the waste products in respiration
water and carbon dioxide
what is anaerobic respiration
this occurs without oxygen and releases less energy but more quickly than aerobic respiration.
what is 1 advantage of anaerobic respiration
Muscles can release energy for a short period when not enough oxygen is
available, e.g. 100m sprints.
what are 2 disadvantages of anaerobic respiration
- Lactic acid is released which is harmful to the body.
- Not suitable for activities that require energy release over a long period
of time, e.g. a long-distance run.
what is oxygen debt
a temporary oxygen shortage in the body tissues because of exercise
when does oxygen debt occur
After using anaerobic respiration to release energy
what are the 2 functions of the respiratory system
- get oxygen into the blood
- remove carbon dioxide from the blood.
what is inspiration
breathing in
what is expiration
breathing out
the respiratory system can be modeled with a bell jar and balloon. how is the model similar to the body? (name 3 reasons)
- approximately the same shape
- inflates and deflates
- domed up position matches position when air is exhaled
the respiratory system can be modeled with a bell jar and balloon. how is the model different to the body? (name 3 reasons)
- has no muscles attached to the ‘ribs’ and so cannot move up/down/in/out
- balloon does not fill the space
- no tubes with terminal alveoli
what are alveoli
- the respiratory surface of the lungs.
- full of air and are covered on the outside by blood capillaries.
what does plasma do in the blood
carries dissolved substances
what is plasma
This is the liquid part of blood. It is pale yellow in colour and is 90% water.
what does the vena cava do in the heart
carries blood from the organs of the body to the right
atrium.
what does the aorta do
carries blood from the heart to the organs of the body.
what do platelets do in the blood
clot the blood
what are 3 characteristics of a red blood cell
No nucleus present
Regular disc shaped
Smaller than white blood cells
what are 3 characteristics of a white blood cell
Nucleus present
Irregular shape
Larger than red blood cells
why is the numbers of organisms in a food chain limited
there is energy lost at each step of a food chain, so there’s less available for
the next animal.
The more energy lost every step, the shorter the food chain.
how is energy lost in animals
- egestion (faeces)
- excretion (urine)
- repair of tissues
- dead animals
why do animals lose more heat than plants
because they have a higher metabolism and they move around
why do warm blooded animals lose more heat than cold blooded animals
because they need to keep their body temperature constant
why is less energy lost if humans eat plants
because the food chain is shorter
what does a pyramid of number show about feeding
they show the number of organisms in a given area
what do pyramids of biomass show about feeding
they show the dry mass of organisms in a given area or volume for every feeding level.
how are alveoli adapted for gaseous exchange
- good blood supply so more gas can be exchanged
- moist lining to dissolve oxygen
- large surface area to increase exchange
- thin walls to encourage diffusion
what is a unicellular organism
a living organism made of only one cell
what are specialized cells
cells designed to carry out a particular role in the body
name 2 examples of specialized cells
- red blood cells are designed to carry oxygen
- Nerve cells help contraction of muscles or the relaxation of muscles
does diffusion require energy to take place
no
