Cells and animals Flashcards
What is movement?
A change in position of parts of an organism or the whole organism (locomotion)
What is a stimulus and what is a response?
Stimulus=change in the environment
Response=how you react to the stimulus
What are the different stimuli?
-touch
-chemicals
-heat
-light
-sound
What is sensitivity?
To be sensitive means to be able to detect a stimulus in the environment using receptors and be able to respond in some what to that stimulus
What is growth?
A permanent increase in size of an organism at some stage during their lifecycle
What is assimilation?
When substances are built up into structures of the body
What is respiration?
Respiration is the chemical reaction in which food is broken down to release energy. CO2 and H2O are also produced as waste products.
Where does respiration occur?
In every cell of every living organism
What gas does respiration require?
Oxygen
What is excretion
Excretion is the process by which organisms remove the waste products produced by metabolism from the body.
What is nutrition?
Nutrition is the process by which organisms obtain the essential substances that are needed for life.
What is heterotrophic nutrition?
Animals and non-green plants cannot make their own food so they depend on plants and other animals.
What does heterotrophic nutrition mean?
Hetero=others Trophic=feeding
What are animals that do heterotrophic nutrition called?
Heterotrophs
Types of heterotrophs, what do each of them feed on?
Carnivores - animals
Omnivores - plants and animals
Herbivores - plants
Parasites - living organisms
Saprotrophs - dead material (play important part in decomposition)
What is autotrophic nutrition?
Green plants make their own food by the process of photosynthesis
What does autotrophic nutrition mean?
Auto=self Trophic=feeding
Explain the process of photosynthesis
Plants take in CO2 (from the atmosphere) and water (from the soil) and build them up into complex food molecules using the energy from the sun (absorbed by chlorophyll in chloroplasts)
What is reproduction?
The production of new organisms either sexually or asexually
Differences between sexual and asexual reproduction
sexual:
2 parents required
involves union of male and female gamete
the offspring only resemble their parents and are not identical to them
few offspring are produced at one time
asexual:
1 paren required
no gametes involved
all offspring are identical to parent
asexual reproduction may take place very quickly and sometimes a very large number of offspring are produced
By who and when was the cell discovered?
Robert Hooke in 1665
What were the first cells observed?
Cork cells, more specifically dead cell walls
Who and when were the first living cells observed?
Antony Van Leeuwenhoek in 1674
What does The Cell Theory say?
- All living organisms are composed of cells, they may be unicellular or multicellular
- The cell is the most basic unit of life
- All cells arise from pre-existing, living cells
How much is a micrometer?
one thousandth of a millimeter
How do microscopes enhance our sight
They magnify things and at the same time resolve them
What is resolving power?
The ability to distinguish between2 objects
What is the maximum magnifying power of a light vs an electron microscope?
light = x400 (3 objective lenses= x4 x10 and x40, eyepiece = x10)
electron = x1,000,000
How much can the naked eye resolve?
one tenth of a mm
What do the electron and light microscopes use to magnify?
light = light and glass lenses
electron = beam of electrons and electromagnets
What do we use to see cells under light microscopes?
Cytoplasm is composed of mainly water, which is transparent to light, this makes it difficult to see the cell so we stain the cell using dyes e.g. methylene blue, iodine
Why can an electron microscope magnify more than a light microscope?
Electron wavelengths are thousands of times shorter than visible light so an electron microscope can resolve object thousands of times smaller
Why is the electron microscope so important?
Because it allowed scientists to see the internal structure of cell’s organelles and enabled them to understand their function
What type of images does the scanning electron microscope produce?
3D
What are the disadvantages of the electron microscope?
-All samples must be completely dry, this means we can’t observe living cells
-images are in black/white
What are the 2 types of cells and what is the difference between them?
Eukaryotic - ‘good or true nucleus’, they have a clearly defined nucleus
Prokaryotic - ‘before the nucleus’, don’t have a clear nucleus, only a long string of DNA
What is a specialized cell?
A specialized cell is designed to do a particular job
What is the structure of the cell membrane?
Bilayer of phospholipids with proteins floating inside. The phospholipids are arranged in the shape of a head(facing inward) and a tail(facing outward), the head is hydrophilic and the tail is hydrophobic.
What is the function of the cell membrane?
It controls what enters and leaves the cell and is said to be selectively permeable. The proteins are important in the active transport of ions and molecules.
What is the structure of the cytoplasm?
Clear jelly, almost 80% water with proteins and other substances dissolved in it.
What is the function of the cytoplasm?
Place where metabolic reactions happen
What is the structure of the nucleus?
largest organelle surrounded by a porous, double membrane. Contains DNA arranged in chromosomes
What is the function of the nucleus?
-Control center of the cell.
-DNA controls the formation and development of cell and how cell should behave
-Controls what chemicals the cell should manufacture
What is the structure of the nucleolus?
Spherical body within the nucleus
What is the function of the nucleolus?
Controls the manufacture of proteins
What is the structure of ribosomes?
Tiny, round objects often attached to endoplasmic reticulum.
What is the function of ribosomes?
Make proteins by joining together amino acids following instructions from nucleolus.
What is the structure of the mitochondria?
Oval or rod shaped structures surrounded by 2 membranes. The inner membrane is highly folded. the folds are called cristae.
What is the function of the mitochondria?
To carry out the chemical reaction of respiration. Food is broken down using O2 to release energy for the cell.
What is the structure of the endoplasmic reticulum?
A network of tubules and sacs called cisternae surrounded by phospholipid membranes. Rough ER is covered with ribosomes.
What is the structure of the Golgi apparatus?
A collection of flattened sacs called cisternae.
What is the function of the Golgi apparatus?
Protein shipping and receiving center of the cell. Receives proteins on the cis face, modifies them and then these proteins are either stored or packaged in envelopes of ER for transport to exterior of cell (via trans face).
What is the structure of lysosomes?
spherical/oval bodies surrounded by a single membrane
What is the function of lysosomes?
store digestive enzymes used to digest bacteria or viruses in the cell or digest/recycle old organelles.
What is the structure of the cell wall?
Rigid - criss cross fibers of cellulose
What is the function of the cell wall?
Support and protect the cell. It is fully permeable.
What is the structure of chloroplasts?
oval structure containing chlorophyll
What is the function of chloroplasts?
chlorophyll absorbs sunlight for the process of photosynthesis
What is the structure of starch grains?
small, round structures found inside chloroplasts
What is the function of starch grains?
How plants store their food
What is the structure of the large vacuole?
Space inside a cell, surrounded by a membrane and containing a solution.
Red blood cell function
Contain haemoglobin to carry
oxygen to the cells
Specialized features suited to the function of red blood cells
- Thin outer membrane allows oxygen to diffuse through easily.
- Bi-concave shape increases the surface area to allow more oxygen to be absorbed efficiently and gives cell a more flexible framework allows cells to squeeze through even the tiniest capillaries.
- No nucleus means that the whole cell is full of haemoglobin which combines with and carries oxygen around the body.
Sperm cell (male gamete) function
To fertilise the egg cell (female gamete)
Specialized features suited to the function of sperm cell
- The head, containing genetic information and a nucleus, has an enzyme to help penetrate the egg cell membrane.
- The middle section, immediately behind the head is packed with mitochondria for energy.
3.The tail or flagellum moves the sperm to the egg
Nerve cell (motor neuron) function
Pass sensory impulses from receptor to an effector
Specialized features suited to the function of nerve cell
- Dendrites to make connections with other neurons.
- Long axon or nerve fibre to carry the impulse to the target organ.
- End plate forms a synapse with an effector (a muscle or a gland).
Leaf palisade cell function
Carries out photosynthesis
Specialized features suited to the function of leaf palisade cell
- Packed with chloroplasts containing the light absorbing pigment chlorophyll.
- Regular shaped, closely packed cells forming a continuous layer for efficient absorption of sunlight.
Guard cell function
Opens and closes leaf pore
Specialized features suited to the function of guard cell
- Regulate the size of leaf pore
- Change shape easily
- Swell up when filled with water
Pollen cell function (male gametes)
Fertilise the ovules (female gametes)
Specialized features suited to the function of pollen cell
- Tiny grain with half the genetic information having been formed by meiosis.
- Have a hard protective outer coat to survive bad conditions.
- Shape and surface of outer coat is adapted to method of dispersal - eg smooth and sticky for insect dispersal, larger
surface area for wind dispersal.
Animal cell vs plant cell
Animal cell:
No cellulose cell wall
No chloroplasts
Small, temporary vacuoles
Irregular shape
Glycogen granules
Plant cell:
Cellulose cell wall
Chloroplasts
Large, permanent vacuole
Regular shape
Starch grains
Plant vs animal
Animal:
No photosynthesis
Body is compacted rather than branched
No chlorophyll present
Moves in search of food at some stage in its life
Protein is not stored
Plants:
Photosynthesis takes place
Body is often branched
Chlorophyll is present
Does not move in search of food
Stores protein
What is a tissue?
A tissue consists of a large number of cells in an organism that have a similar structure and function
e.g. connective tissue, nervous tissue, muscle tissue, epithelial tissue
What is an organ?
An organ is a group of tissues that perform a specific function
e.g. brain, heart, kidneys, lungs
What is an organ system?
An organ system is a group of organs that work together to carry out a particular function
e.g. muscular system, skeletal system, nervous system, circulatory system
What is an organism?
Various organ systems together make up an organism
What is the nervous system made up of, what’s it’s function?
brain, spinal cord, sense organs and nerves.
It sends nerve impulses to control all the other systems.
What is the muscular system made up of, what’s it’s function?
skeletal muscle.
responsible for locomotion and movement of the body parts.
cardiac muscle.
pumps blood.
smooth muscle.
controls the movement of materials inside the body.
What is the skeletal system made up of, what’s it’s function?
bones and cartilage.
supports the body, protects soft tissues, stores calcium and produces blood cells.
What is the reproductive system made up of, what’s it’s function?
testes (males), ovaries (females).
concerned with gamete production and transfer and maintenance of secondary sexual characteristics.
What is the digestive system made up of, what’s it’s function?
mouth, oesophagus, stomach, intestines, liver and pancreas.
These organs ingest, digest and absorb.
What is the urinary system made up of, what’s it’s function?
kidneys and bladder.
produce urine and remove it from the body.
What is the respiratory system made up of, what’s it’s function?
lungs, trachea, bronchi and bronchioles
maintains the correct concentration of carbon dioxide and oxygen in the body.
What is the circulatory system made up of, what’s it’s function?
heart and blood vessels.
transportation system of the body.
