science Flashcards
what is a cell?
the cell is the smallest working unit of a living thing (organism)
independent variable
being changed
dependent variable
being measured
fixed/control variable
staying the same
hypothesis
prediction
name of the man who first said the word cell
robert hooke in 1665
what does unicellular mean
made of just one cell, for example, bacteria.
multicellular
made of many cells, for example, humans.
levels of organization
cells - tissues - organ - organelle - organ system - organism
what is tissue?
A tissue is a group of cells that work together to carry out a similar function. e.g Blood is a tissue which consists of blood cells (red blood cells, white blood cells and platelets) that work together to transport oxygen and other substances around the body.
organ
An organ is a group of tissues that work together to carry out a similar function
Example: The Heart, Liver, Kidneys, etc.
An organ does not have to consist of only one type of tissue
Example – the heart consists of blood tissue, nerve tissue, muscle tissue.
organ system
An organ system is a group of organs that work together to carry out a similar function.
organism
An organism is a group of organ systems that work together to carry out a similar function.
what does an animal cell consist of?
ribosome, cytoplasm, nucleus, cell membrane, mitochondria
what is membrane?
Structure:
Outer cell covering
Made up mainly of fat
Function:
Keeps the contents of the cell in place
Acts as a form of protection
Controls what enters and leaves the cell
cytoplasm
jelly like substance, composed of 80% water, salts, glucose
cell organelles float within this substance + cell activities occur here
membrane-bound organelles
nucleus, mitochondria, ribosomes
contents of a nucleus
genetic material, chromosomes made up of genes, genes made up of dna
function of the nucleus
acts as the brain of the cell, in charge of all cell activities, cell manager,
mitochondrion (mitochondria)
The place where energy is released from nutrients by respiration.
ribosomes
Their function is to produce proteins such as the hormone insulin, the enzyme amylase, and collagen for the skin.
small vacuole
Used for temporary storage of food and waste
plant cell
cytoplasm
cellulose cell wall
only in plant cells + supports, shapes and strengthens the cell
chloroplast
where photosynthesis occurs
photosynthesis
Photosynthesis is the way in which green plants make their own food using light.
large vacuole
Stores water, sugar and waste.
Also helps to give
structure to the cell.
characteristics of life
reproduction, movement, respiration, response, nutrition, growth and excretion
the keywords of a microscope (study image on slide 45)
Microscope
Eyepiece lens
Nosepiece
Objective lenses
Stage
Lamp
Coarse focus
Fine Focus
what does the eyepiece do
magnifies the sample x10
objective lens
above the stage, has 3 lenses that magnify the sample by 4, 10 or 40
stage
where you hold your sample
coarse focus knob
to focus sample you are looking t
fine focus knob
further sharpens image and for delicate focusing at high power
light
supplies light to the object
diaphragm
controls the amount of light
why do we need food?
energy, growth, repair, to prevent deficiency disease
main types of nutrients in food
protein, carbohydrates, fat ,vitamins, minerals, water
sources of protein
lean meat, fish eggs, poultry, beans, lentils.
function of protein in body
growth, repair of tissue
types of carbohydrates
starch, sugar, fibre
function of carbohydrates in body
starch = energy
sugar = energy
fibre = causes peristalsis in the digestive system, prevents constipation
fat
you can get it from vegetable oils function = cell membranes
vitamins
vitamin C + D
vitamin c
citrus fruits, kiwi, blackcurrants
vitamin d
sunlight, dairy foods, supplements
vitamin c + d function in body
vitamin c - making new cells
vitamin d - healthy bones, wellbeing
vitamin c + d deficiency disease
c - scurvy
d = rickets
minerals
calcium , iron
sources of iron and calcium
calcium : dairy foods, tinned fish
iron : red meat, green vegetables
calcium + iron function in body
calcium - strong bones and teeth
iron - needed for haemoglobin
calcium + iron deficiency disease
iron - anaemia
calcium - osteoporosis
water function in body
maintain body at 37 degrees
digest =
break down food
components of the digestive system (see slide 10)
mouth and mouth cavity, pharnyx, oesophagus, liver, stomach, gallbladder, pancreas, small intestine, large intestine, rectum and anus
function of salivary glands
produces amylase, amylase is an enzyme that helps break down starch
function of liver
produces bile to aid digestion of fat
gallbladder function
stores bile until small intestine needs it
function pancreas
make enzymes to digest food
small intestine function
digests food and absorbs it into blood
five steps of getting nutrients
ingestion, digestion, absorption, assimilation, egestion
meanings of the five steps of getting nutrients
Ingestion: eating
Digestion: breaking down food
Absorption: food passing into blood
Assimilation: food being used by the cells
Egestion: passing out unabsorbed food (faeces)
types of digestion
chemical, mechanical
teeth and their functions
Incisors (4)
Cut and slice food.
Canines (2)
Grip and tear food.
Premolar (4)
Chew and grind food.
Molars (6)
Chew and grind food.
peristalsis
used to push food along system only occurs in muscles of digestive system
enzymes
A protein that alters the speed of a chemical reaction in an organism
amylase
enzyme that breaks down starch into a sugar called maltose
amylase - ? - ?
AMYLASE - STARCH - MALTOSE
maltase - ? - ?
MALTASE - MALTOSE - GLUCOSE
