Biology 1 Flashcards
What are microscopes used for?
To observe small objects in detail
What do animal cells contain?
Nucleus
Cytoplasm
Cell membrane
Mitochondria
What do plant cells also contain (in addition to the animal cells)?
Chloroplasts
A vacuole
Cell wall
What do specialised cells have?
Specialised cells have a shape and structure suited to carry out a particular job
What is diffusion?
Diffusion is the movement of particles from high concentration to low concentration
What is a uni-cellular organism?
It contains only one cell
What is a multi-cellular organism?
They are made up of many cells, grouped into tissues, working together to form organs that work in groups to form organ systems
What is the skeleton made up of?
Bones
What are the four important functions of the skeleton?
Support
Protection
Movement
Making blood cells
What are joints?
Joints occur where two or more bones join together
What does cartilage do?
Cartilage in joints stops bones rubbing together
What holds bones together?
Ligaments
What joins muscles to bones?
Tendons
What are antagonistic muscles?
They are pairs of muscles that work together at a joint. When one contracts the other relaxes.
How does a light microscope work?
Light shines through a specimen
A series of lenses then magnifies the image
The specimen, such as a sample of cells, must be very thin, so it needs to be supported on a thin glass slide
The slide and specimen are transparent and allow the visible light to pass through to the magnifying lenses
A microscope is very _______ and must be treated with great ______
Fragile
Care
How do you lift the microscope?
You lift the microscope with 2 hands
One on the body and one under the base
How do you adjust the objective lens?
Adjust the objective lenses so that the lowest power lens is over the hole in the stage
For the objective lenses, how do you know which is the lowest power lens?
It is the shortest, it has a red band on it and it has the number 4 on it
Why is it important to have your head at the side of the microscope when turning the coarse focusing wheel to make the gap between the stage and the objective lens as small as possible?
So you do not smash the lens into the glass
When you put the microscope slide onto the stage, what do you use to fix it on?
Clips
How do you adjust the light source on the microscope?
This can be done by turning the iris diaphragm so that the field of view is bright but not dazzling
If using a mirror and a lamp, adjust the angle of the mirror
Look down the eyepiece lens and use the coarse focusing knob to slowly move the stage _____ from the objective lens until you can see a very clear, sharp image. Adjust the __________ to clarify further.
Away
Fine focusing knob
What do you do if you need greater magnification?
Turn to a higher power objective
If the power of your eyepiece lens is x10 and the power of the objective lens is also x10, then what is the magnification?
100 times
What is the simplest unit of plant and animals?
Cells
How many cells are in the human body?
50 million - 100 million cells
What is the cytoplasm?
It contains water and dissolved chemicals
Most of the chemical reactions, such as respiration, occur here
What is the cell membrane?
It surrounds the cell and protects it from its environment.
It controls the entry and exit of dissolved substances
What is the nucleus?
It contains the genetic material called DNA which makes up genes and chromosomes
The DNA carries the instructions controlling the activities and characteristics of the cell
What is the mitochondria?
This is where sugar and oxygen react together to release energy from the sugar.
The number of these structures present in the cell tells us how much energy that cell must produce to survive
Example: muscles cells have a large number of mitochondria
Which stain do you use to see colourless cells more clearly (example: cells from the lining of your cheek)?
Methylene blue
Give a brief description of the nucleus
Controls all the cell’s activities
Give a brief description of the cytoplasm
The living, jelly-like part of the cell where all the chemical reactions of the cell take place
Give a brief description of the cell membrane
Surrounds the living parts of the cell and controls what materials enter and leave the cell
Give a brief description of the cell wall
A thick wall surrounding the cell membrane, made up of cellulose
Give a brief description of a vacuole
A liquid-filled space in the centre of the cell
Give a brief description of chloroplasts
Contains the green pigment chlorophyll and are the site of food manufacture in the cell
Give a brief description of mitochondria
Here sugar and oxygen react together to release energy from the sugar
What are the cell structures that are part of both plant and animal cells?
Mitochondria
Nucleus
Cell membrane
Cytoplasm
What are the cell structures that are found only in plants?
Cell wall
Chloroplasts
Vacuole
In multicellular organism, we find that different cells carry out different tasks and function, they have become ________
Specialised
What are the plant cells found in the upper part of leaves called?
Palisade cells
What makes the leaves green?
Chlorophyll
What is Chlorophyll and where is it found?
Chlorophyll is a chemical essential for photosynthesis
Chlorophyll is found in chloroplasts
What is the job of palisade leaf cells?
To produce glucose from carbon dioxide and water using energy from the sun
What do the palisade leaf cells look like?
They are long and thin and are arranged like bricks in a row
What does a root hair cell look like?
Why does it look like this?
What is the job of the root hair cell?
What does the root hair cell NOT have?
It is long and thin
This gives it a large surface area
Its job is to absorb water and minerals from the soil
Root hair cells do NOT have chloroplasts
What do sperm cells resemble and why?
Tadpoles
They both have long, lashing tails to help them swim
Sperm cells have plenty of ________
Mitochondria
Why does the sperm cell have a lot of mitochondria?
Mitochondria provides energy for the long swim to the egg cell
What is the role of the sperm cell?
To fertilise an egg
Under a microscope, what does nerve cells look like?
Like trees in winter
At one end, surrounding the nucleus, are lots of ‘branches’
There is long, thin ‘trunk’ ending in a cluster of ‘roots’
What is the function of a nerve cell?
To receive and pass on messages, in the form of electrical signals, to different parts of the body
Describe a red blood cell
They are shaped like ‘donut’ peaches
They do not have a nucleus because they are designed to carry as much oxygen as possible
They are packed with a special, oxygen-carrying molecule called haemoglobin
What is the function of the palisade leaf cell?
What is their adaptation?
To captures as much light as possible to enable photosynthesis to occur
They have lots of chlorophyll
What is the function of the root hair cell?
What is their adaptation?
Take in water and minerals from the soil
They have a long finger-like projection with very thin walls and a large surface area
What is the function of the sperm cell?
What is their adaptation?
They carry genetic material to the egg cell
They have a tail to help them swim and reach the egg cell
What is the function of the nerve cell?
What is their adaptation?
They carry information to and from the brain
These cells have very long, thread-like projections
What is the function of the red blood cell?
What is their adaptation?
They carry oxygen in the blood to all the other cells in the body
They have no nucleus
What is the function of the egg cell?
What is their adaptation?
When the egg and sperm cells join they make a new individual
They have a large cytoplasm and food for the growing embryo
In plant cells, what traps light for photosynthesis?
Chloroplasts
In plant cells, what is made of cellulose?
Cell wall
In the freshwater environment water enters the algal cell. What is the name of the process by which water moves into cells?
Osmosis
Give the reason why the algal cell does not burst
Because it has a strong rigid cell wall on the outside of the cell membrane
What are examples of specialised plant cells?
Palisade cells
Root hair cells
What are examples of specialised animal cells?
Sperm cells
Red blood cells
Egg cells
What are 2 examples of uni-cellular organisms?
Amoeba
Euglena
Give some features of amoeba
No fixed shape
It lives in fresh water, salt water, wet soil and sometimes even in humans
They move by changing the shape of their body
They can move in any direction
Name 2 structures that an amoeba has in common with an animal cell
Cell membrane
Nucleus
What does an amoeba have in common with a plant cell?
Vacuole
Describe how an amoeba feeds
It takes food by extending arm-like structures called pseudopodia from any part of its body
Pseudopodia surrounds food particles
The food particles is trapped in a vacuole
Digestive enzymes break down the food
The nutrients are absorbed
Waste is thrown out of the body
Euglena is found in _______ and have features of both ______ and ______ cells
Freshwater
Animal
Plant
In the Euglena, what are the roles of the eye-spot and flagellum?
Eye-spot: detects where there is light
Flagellum: allows the cell to move
How do uni-cellular organisms reproduce?
Binary fission
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration
How do substances move in and out of cells?
What are some examples of substances?
By diffusion
Oxygen, glucose and carbon dioxide
How does water enter the plants from the soil?
Though the root hair cells by diffusion
What is the function of a cell?
It is the building blocks of life
What is the function of tissue?
It is a group of similar cells working together
What is the function of an organ?
It is a group of tissues working together
What is the function of an organ system?
It is a group of organs working together
What is the function of an organism?
It is a group of organ systems working together
The levels of organisation are put into a ________ based on their size and complexity
Hierarchy
What are the levels of hierarchy from least complex to most complex?
Give an example
Cells - muscle cells Tissues - muscle tissues Organs - heart Organ system - circulatory system Organism - human
What is the function of the circulatory system?
What are the major organs?
It permits blood to circulate and transport nutrients.
Major organs - heart, lungs, arteries and veins
What is the function of the respiratory system?
What are the major organs?
To deliver air to the lungs. It allows diffusion of oxygen into the bloodstream. It receives waste carbon dioxide from the blood and exhales it
Major organs - airways, lungs, muscles of respiration
What is the function of the immune system?
What are the major organs?
It neutralises pathogens like bacteria.
It protects the body against infections.
Major organs - tonsils, lymph nodes, thymus, spleen, bone marrow
What is the function of the digestive system?
What are the major organs?
It breaks down food into small molecules which are then absorbed into the body.
Major organs - mouth, oesophagus, stomach, small intestine, large intestine, pancreas, liver, gallbladder
What is the function of the musculoskeletal system?
What are the major organs?
It supports the body, allowing motion and protecting vital organs
Major organs - bones, muscles
What is bone?
Bone is a living tissues with a blood supply that is growing and changing all the time. Together, the bones of your body make up your skeleton
Name the main parts of the skeleton
Skull Jaw bone Clavicle Shoulder blade Sternum Humerus Radius Ulna Ribs Back bone Pelvis Femur Knee cap Tibia Fibula
What are the 4 main roles of the skeleton?
Support
Protection
Movement
Making blood cells
What is bone made up of?
Long protein fibres (organic)
Mixtures of calcium compounds (inorganic)
What does the mineral component in bone do?
It strengthens the bone
What does the organic component of bone do?
It makes the bone more bendy and less brittle
What are joints?
Joints occur where 2 or more bones join together
Most of our joints are ______, but some of the bones in our skeleton are joined _____ together and cannot move
Give an example
Flexible
Rigidly
The joints of your skull were flexible before birth, but became fixed after you were born
Explain how flexibility of the skull joints is an advantage when a baby is born
To make childbirth easier.
It makes it easier for the head to pass through the birth canal
Why is it important for the skull joints to become fixed after birth?
To protect the brain because the brain is a soft organ
What are the different types of joint?
Fixed joints
Hinge joint
Ball and socket joint
What is the function of the hinge joint?
Give examples
It allows bending in only one direction
Examples: ankle, elbow, knee, fingers
What is the function of the ball and socket joint?
Give examples
It allows twisting and bending
Examples: shoulder, hip
What are the ends of bones covered in?
Cartilage
What is the function of cartilage?
Cartilage is softer than bone. It reduces friction and acts as a shock-absorber.
If your bones were not covered in cartilage, they would directly rub against each other and cause a lot of pain
Where else is cartilage found (besides the end of bones)?
Nose, earlobes, breastbone
Besides bone and cartilage, what else does joints contain?
Joints also contain fluid which keeps the cartilage slippery and allows smooth movement
What are the bones of a joint held together by?
Ligaments
What are tendons?
They attach muscles to bone.
They are strong fibres that do not stretch.
How do muscles bring about movement?
They can only bring about movement by contracting.
What does contracting mean?
The muscles get shorter and pull on the tendon attached to the bone, causing the bone to move
Muscles can only ____, they cannot _____
Can only pull
Cannot push
At many joints, muscles have to work in ______. We call these __________.
Pairs
Antagonistic muscle pairs
Give an example of antagonistic muscle pairs
Biceps at the front of your arm
Triceps at the back of your arm
How do muscles work together to bend and straighten the arm?
When the biceps muscle contracts and the triceps relax the arm bends
When the triceps muscle contracts and the biceps relax, the arm straightens
What are special features that help a cell or organism carry out its function?
Adaptations
What are muscles working in unison to create movement? When one muscles contracts that other relaxes
Antagonistic muscle pair
What is the tissue found inside some bones where new blood cells are made?
Bone marrow
What is the smooth tissue found at the ends of bones which reduces friction between them?
Cartilage
What is the unit of a living organism? It contains parts to carry out life processes.
Cell
What surrounds the cell and controls the movement of substances into and out of the cell?
Cell membrane
What strengthens the cell? In plants it is made from cellulose.
Cell wall
What contains the green pigment chlorophyll?
What does chlorophyll do?
Chloroplast
Chlorophyll absorbs light energy during photosynthesis
What transports substances around the body?
Circulatory system
What is the jelly-like substance where most chemical reactions take place inside cells?
Cytoplasm
What is one way for substances to move into and out of cells, from a high concentration to a low concentration?
Diffusion
What breaks down and then absorbs food molecules?
Digestive system
What protects the body against infections?
Immune system
Where are places where bones meet?
Joints
What connects bones in joints?
Ligaments
What is the part of the cell where energy is released from food molecules (glucose) during respiration?
Mitochondria
What are living organisms made up of more than one type of cell?
Multicellular
Which system has muscles and bones working together to cause movement and support the body?
Muscular skeletal system
What contains the genetic material (DNA) of the cell and controls the cell’s activities?
Nucleus
What is a group of different tissues working together to carry out a job?
Organ
What produces sperm and eggs? In a female this is where the foetus develops
Reproductive system
What replaces oxygen and removes carbon dioxide from the blood?
Respiratory system
What connects muscles to bone?
Tendons
What are groups of cells of the same type?
Tissue
What are living organisms made up of one cell?
Uni-cellular
What contains liquid (sap) and can be used by plants to keep the cell rigid and store substances?
Vacuole
What is the function of the cell membrane?
It controls the passage of substances in and out of the cell
What is the function of the cell wall?
It strengthens the cell
What is the function of the cytoplasm?
It is where most of the chemical reactions take place
What is the function of chromosome?
This is where the genes are
What are two differences between an animal cell and the cell of a bacterium?
Bacteria cells do not have a cell nucleus
Bacterial cells do not have mitochondria
Give one way that a cell wall is different from a cell membrane
The cell wall is completely permeable
The cell membrane is semi-permeable
How many bones are in the human body?
206 bones
