7D Organisms Flashcards
Apart from support and movement, what are the functions of the skeleton?
Protection of vital organs, production of blood cells, storage of minerals
What is the function of the bone marrow?
Produces blood cells
How are bones attached to each other?
Ligaments
What is the function of a tendon?
To attach muscle to bone
Where is cartilage found?
At the joints of bones
Explain why cartilage is important.
Reduces friction, prevents the ends of bones grinding against each other during movement and wearing away
How are hinge joints and ball and socket joints different?
Hinge joints only move in one direction, ball and socket joints can move all around.
Describe how muscles move bones.
A muscle contracts and pulls a tendon which pulls a bone.
What happens to muscle cells when they contract?
Get shorter and fatter
What happens to muscle cells when they relax?
Get longer and thinner
Explain why muscles which moves bones need to work in pairs.
Muscles can only pull bones, two muscles are needed to pull bones in opposite ways
What are antagonistic muscles?
Pairs of muscles which work in opposite ways
Give an example of a pair of antagonistic muscles.
Biceps and triceps, quadriceps and hamstrings
What happens to your forearm if your biceps contract and your triceps relax?
Forearm moves up
How do your muscles allow you to hold objects in your hand?
Exert a force against gravity
A bodybuilder is lifting a dumbbell which weighs 600N. How much force are their muscles exerting?
600N
What are the three bones in the human leg?
Femur, tibia, fibula
Name the two muscles in the thigh.
Quadriceps (front) and hamstrings (back)
To bend your leg at the knee, which muscles must contract?
Hamstrings
To straighten your leg, which muscles must contract?
Quadriceps
What happens if too much tension is put on a tendon?
It can snap or pull
Why do ligaments need to be elastic?
When the joint is bent, the ligament can stretch and then return to its normal shape without snapping
What might happen if you pulled a ligament?
It would be painful to bend a joint
Which bones are found in our toes?
Phalanges
Why is it important for bones to contain collagen?
So they can bend a little without breaking
How do doctors usually fix a fracture in the arm or lower leg?
Fibreglass cast
What is a compound fracture?
Where the bone breaks the skin
Why is the risk of infection higher for a compound fracture?
It is easier for microorganisms to get into the blood through the wound
What is osteoporosis?
A condition where bone density decreases and bones become fragile
Give two possible risk factors for osteoporosis.
Menopause, getting older, smoking, heavy drinking, family history, underweight
Give two ways a doctor can help treat osteoporosis.
Medicines to help strengthen bones, calcium and vitamin D supplements
Why can’t we completely prevent osteoporosis?
Cannot change family history, can only try to reduce the chance of developing it
What are cells?
The basic building blocks of life
What is formed from a group of tissues working together?
An organ
Name the 5 levels of organisation from smallest to largest.
Cell, tissue, organ, organ system, organism
What is a specialised cell?
A cell which is adapted to perform a certain function
Name the organs present in the digestive system.
Stomach, small intestine, large intestine, pancreas
What is the function of the circulatory system?
To pump blood around the body
What type of tissue is the heart made from?
Muscle tissue
How are nerve cells specialised for their function?
They are very long to connect different parts of the body
What is an organelle?
A part of the cell, e.g. a nucleus
Describe the function of the cell membrane.
Separates the inside and outside of the cell, allows substances in or out of the cell
Where do most of the cell’s reactions take place?
Cytoplasm
Which part of the cell controls its activities and contains the DNA?
Nucleus
What is the function of the mitochondria?
Provide energy by respiration
Name three organelles which are found in plant cells but not in animal cells.
Cell wall, vacuole, chloroplast
Which organelle is responsible for providing the plant with food?
Chloroplast
What is the difference between a eukaryotic and prokaryotic cell?
Eukaryotic cells contain a nucleus but prokaryotic cells do not
What is a specialised cell?
A cell which is adapted to perform a certain function
How are red blood cells adapted to fit through capillaries?
Small and flexible so they do not get stuck
Why do nerve cells have a long, thin axon?
To carry electrical signals long distances around the body
Why are muscle cells bundled together?
So they work together to pull on a bone
Why do muscle cells and root hair cells need lots of mitochondria?
For energy
How do root hair cells speed up the absorption of water and minerals?
Having a projection into the soil giving them a large surface area
Which cell is responsible for photosynthesis in the plant?
Palisade cells
How does a microscope allow us to see small objects like cells?
Using lenses to focus light and magnify small objects
Why do we add iodine to the onion cells?
To make it easier to see them
How do we keep the specimen in place on the microscope slide?
By placing a cover slip on top of the specimen
Why must you be careful not to create air bubbles when preparing the specimen?
You could mistake them for parts of the cell
Name the part of the microscope where we place the slide.
Stage
Why do we lower the stage to its lowest point before looking through the eyepiece?
To reduce the chance of the slide and objective lens coming into contact with each other and potentially breaking
Which objective lens should we use first?
The lowest power lens
How do you find the total magnification you are using?
The objective lens multiplied by the eyepiece
Why do unicellular organisms have to be very well adapted to their environment?
They do not have specialised cells to carry out different functions
How are bacterial cells similar to plant and animal cells?
They have cytoplasm and a cell membrane
What is the difference between a eukaryotic and prokaryotic organism?
A eukaryotic organism has cells with a nucleus, prokaryotic cells do not
What group of organisms may be unicellular or multicellular?
Fungi
Why are yeast cells classed as eukaryotic?
They have a nucleus
Describe one way yeast are useful to us.
Brewing beer/wine – they produce alcohol Baking bread – they make bread rise
In what way do protozoa act like animals?
They hunt for their food
How are protozoa different to plant cells?
They do not have a cell wall or chloroplasts
