Structure and functions in living organisms Flashcards
Covers these sub-topics: Level of organisation, Cell Structure, Biological molecules, Movement of substances into and out of cells, Nutrition, Respiration, Gas Exchange, Transport, Excretion and Co-ordination and response.
Name the organelles in an animal cell
-Nucleus
-Cell membrane
-Cytoplasm
-Mitochondria
-Ribosomes
Name the organelles found in a plant cell
-Nucleus, cell membrane, cytoplasm, mitochondria, ribosomes
+
-cell wall, vacuole, chloroplasts
List the following in size order:
-Cells, Organs, Organelles, Systems, Tissues
-Organelles, Cells, Tissues, organs and systems
What is the function of the nucleus
Stores DNA and co-ordinates the cell’s processes
What is the role of the cytoplasm
Jelly-like fluid that supports and suspends the cell organelles
What is the role of cell membrane
Regulates the movement of substances in and out of the cell.
What is the role of the cell wall
Gives the cell structure and shape, prevents plant cells from bursting when it absorbs water.
What is the role of the mitochondria
This is where respiration takes place
What is the role of the chloroplasts
This is where photosynthesis occurs
What are stem cells?
-Stem cells are unspecialised cells
-They have the ability to differentiate into many cell types.
Where are stem cells found?
-Bone marrow
-Many organs
-Eyes
-Umbilical cord
-Embryo (not adult stem cells)
Where are stem cells found in plants?
In the stem.
What is differentiation?
When cells can turn on/off different genes, by translation or transcription of genes.
When a cell changes to become specialised for it’s job
How are cells specialised?
They have different structures to suit their different functions
How do stem cells split?
They divide by mitosis frequently.
What can stem cells be used for?
To cure diseases and they can differentiate into any cell type.
What are issues with using stem cells for curing disease?
-Stem cells grown in labs can become contaminated with a virus making the person sicker.
-Some people are against stem cell research as an embryo can be considered as a human life.
What elements are present in carbs?
Carbon, Hydrogen and oxygen.
What elements are present in proteins
Carbon, Nitrogen, Hydrogen and Oxygen
What elements are in lipids
Carbon, Hydrogen and oxygen.
What are proteins made up of
Long chains of amino acids
What are carbs made up of
Starch and glycogen are made up of lots of simple sugars like glucose or maltose.
What are lipids made up of
They are built from fatty acids and glycerol.
How are plants adapted for photosynthesis?
Leaf cells contain chloroplasts which contain chlorophyll which absorbs sunlight and carries out photosynthesis.
What are magnesium ions needed for?
They are needed for chlorophyll
What are nitrate ions needed for?
Amino acids
What is the role of the mouth?
-Salivary glands in the mouth produce amylase enzyme in the saliva
-Teeth break down food
What is the Oesophagus
-The muscular tube that connects the mouth and stomach.
What is the alimentary canal?
The gut
Role of the liver
-Where bile is produced
Role of Gall Bladder
-Where bile is stored
What is Bile?
Bile is an alkaline that neutralises stomach acid so the enzymes in the small intestine can work at optimum pH.
-Bile also emulsifies fats increasing speed of digestion.
What is the role of the small intestine?
-Produces protease, amylase and lipase enzymes to complete digestion
-This is also where the nutrients are absorbed out of the gut into the body
What are the 2 parts of the small intestine?
The first bit is the duodenum and the last part is ileum.
Role of Pancreas
-Produces protease, amylase and lipase enzymes. It releases these into the small intestine.
Role of the Large Intestine
-Where excess water is absorbed from the food.
Role of the rectum?
-The last part of the large intestine
-Where the faeces are stored
Role of the stomach`
-Pummels the food with its muscular walls
-It produces pepsin
-Produces hydrochloric acid to kill bacteria and give protease enzyme to work.
How is the small intestine adapted for absorption of food?
-Large surface area for absorption because walls of small intestine are covered in millions of villi.
-Villi has a permeable layer of surface cells and a very good blood supply to assist quick absorption.
Where does gas exchange occur in humans?
The alveoli
How are alveoli specialised for gas exchange?
-Very large surface area
-Moist lining for gases to dissolve in
-One cell thick
-Permeable walls
Role of the intercostal muscles and diaphragm
They contract during breathing in and relax during exhalation. (Diaphragm moves up when relaxing)
Thorax
The top part of the body seperated by the diaphragm
Intercostal muscles
They run inbetween the ribs
Rib-cage
Protect the vital organs such as lungs
Trachea
This is where the air that is breathed in goes
Bronchi
Tubes that go from trachea to each lung.
Bronchioles
Small tubes that are connected to alveoli and bronchus
Alveoli
This is where gas exchange happens, small bags connected to bronchioles.
What are the lungs surrounded by
Pleural membranes
How can smoking cause coronary heart disease
-Carbon monoxide in cigarette smoke reduces the amount of oxygen the blood can carry
-Blood pressure increases, damaging artery walls leading to blood clots in the artery.
How can smoking cause cancer
Because Tobacco smoke contains carcinogens, chemicals that lead to cancer.
How can smoking cause diseases like emphysema
-Smoking damages the walls inside the alveoli reducing the SA for gas exchange.
Effect of Tar on the body from smoking
Tar damages the cilia in the lungs and trachea, leading to the build up of mucus leading to illness like chest infection
Why do multicellular organisms need a variety of substances to live
The cells in all living organisms need a variety of substances to live, such as water, minerals and sugars.
They also need to get rid of waste substances
Why do unicellular organisms rely on diffusion?
The substances can diffuse directly into and out of the cell across the cell membrane. The rate of diffusion is quick as distance is short.
