Cells, Food tests, Enzymes Flashcards
Nucleus
Controls the cell, contains genetic material
Cytoplasm
Supports cell, site of cells’ chemical reactions.
Cell membrane
Holds cell together
Controls substances entering and leaving the cell
Cell wall
Extra support for cell
Defines shape
Chloroplasts
Contains chlorophyll pigments that absorb light for photosynthesis.
Vacuole
Filled with cell sap
Keeps the cell’s shape
Mitochondria
Site of aerobic respiration
Energy released for cell
Ribosomes
Site of protein synthesis
Animal cell organelles
Cell membrane, cytoplasm, ribosomes, nucleus, mitochondria
Plant cell organelles
Cell membrane, cytoplasm, ribosomes, nucleus, mitochondria, cell wall, chloroplasts, vacuole
Test for Glucose/ reducing sugars
- Place food sample in a test tube.
- Add enough Benedict’s solution for sample to turn blue.
- Heat test tube in a boiling water bath for 5 minutes.
- Take the test tube out and observe the colour.
Positive result is from blue to orange/ brick red.
Safety precautions for reducing sugars test
Handle test tube with tongs.
Wear safety goggles and heatproof gloves.
Tie hair, wear a lab coat. Goggles.
Test for Starch
- Place food sample in test tube.
- Add a few drops of iodine to the food sample.
- Observe the colour.
Positive result is from orange/brown to blue/black
Test for Protein
- Place food sample in test tube.
- Add drops of Biuret solution to the food sample.
- Observe colour.
A positive result is from blue to violet/purple
Test for fat
Place food sample into test tube. Add ethanol to the sample and shake. Add water and also shake.
Positive result is colourless to milky white emulsion.
Cells
The functional building blocks of all living things.
Organelle
Part of a cell
Tissue
A group of specialised cells that have a similar structure and function working together.
Organ
Contains different tissues, working together to carry out particular functions.
Organ system
Many organs working together. The different organ systems work together in an organism.
Bacteria
Single celled organism
Doesn’t have nucleus
Fungi
Single or multicellular
Organelles- Same as plant cell but no chloroplasts
Cell wall made out of chitin
Glycogen store
Can be pathogenic
Eukaryotic
Protoctista
Single or multicellular organisms
Similar to animal cells but can have chloroplasts
Enzyme for starch
amylase
Enzyme for proteins
protease
Enzyme for lipids
lipase
Starch is broken down into
simple sugars/glucose
Proteins are broken down into
amino acids
Lipids are broken down into
fatty acids and glycerol
Relationship between rate of reaction and temperature with enzymes
Rate of reaction increases with temperature at 40oC. After 40oC collisions are too violent and the active site is denatured.
Relationship between rate of reaction and pH.
All enzymes have an optimum pH. At extremes of pH the active site can change shape causing the enzyme to become denatured. Reaction cannot take place and the change can be irreversible.
Multicellular kingdoms
Plant, animals, fungi
Unicellular kingdoms
bacteria, protoctists, fungi
Which kingdom does not contain a nucleus?
Bacteria (prokaryotes)
Which kingdoms have a starch carbohydrate store?
Plants, protoctists
Which kingdoms have a glycogen carbohydrate store?
Animal, bacteria, fungi, protoctists
Cell wall in plant?
Cellulose
Cell wall in fungi?
Chitin
What are Prokaryotes?
Small, single-celled organisms that lack a nucleus and other membrane-bound organelles. Bacteria.
What are Eukaryotes?
Uni or multicellular organisms that contain a nucleus and other membrane-bound organelles. Animals, plants, fungi, protoctists
How do plants store carbohydrates?
As starch or sucrose
How do animals store carbohydrates?
As glycogen
How do fungi store carbohydrates?
As glycogen
What do fungi not have?
Chloroplasts
Describe viruses.
A strand of genetic material surrounded by a protein coat. They are not cells or alive. They do not have organelles.
How do viruses reproduce?
They enter a host cell.
What are pathogens?
Microorganisms which cause infective disease.
What can be pathogenic?
All viruses, some bacteria, protoctista and fungi.
Which kingdoms feed by saprotrophic nutrition?
Fung and some bacteria.
What is saprotrophic nutrition?
Secreting extracellular digestive enzymes onto the food and then absorbing the digested molecules.
Describe the structure of DNA.
Double helix shape. Sugar-Phosphate backbones. Phosphate and a nitrogenous base. ATCG.
