Topic 1 - Key Concepts Flashcards
What are the five main structures found within an animal cell?
Cell Membrane
Cytoplasm
Ribosomes
Nucleus
Mitochondria
What is the role of the cytoplasm?
Provides space for chemical reactions to take place
What is the role of the ribosomes?
Help to carry out protein synthesis
What is the role of the mitochondria?
It is the site of aerobic respiration
What are the three structures that are in plant cells but not animal cells?
Cell Wall
Vacuole
Chloroplasts
What is the role of the cell wall?
Strong cellulose to support and protect plant structure
What is the role of the vacuole?
Supports cell structure by filling with sap
What is the role of chloroplasts?
Absorb light energy used for photosynthesis
What type of cells are animal and plant cells classified as?
Eukaryotic
What makes a cell eukaryotic?
If the cell contains a nucleus holding the cell’s DNA
What makes a prokaryotic cell?
If the cell contains no nucleus and the DNA is found in the cytoplasm
What are the 3 main differences between a eukaryotic and prokaryotic cell?
- Prokaryotic contain no chloroplasts or mitochondria
- Prokaryotic cells have no nucleus
- Prokaryotic cell walls aren’t made of cellulose
What is the definition for a specialised cell?
Cells that change their size, shape and structures to carry out specific functions in organisms
What are four examples of specialised cells?
Neurones
Sperm cells
Egg cells
Ciliated epithelial cells
What are the main structures within a neurone excluding the normal animal cell structures?
Dendrons
Dendrites
Myelin sheath
Nerve endings
Long axon
What is the role of the dendrons in a neuron cell?
They are used to receive electrical impulses from other neurones
What is the role of the nerve ending in a neuron cell?
These can connect to receptors or effectors like muscles
What is the role of the long axon in a neuron cell?
They help transmit electrical signals up and down the body
What is the role of the myelin sheath in a neuron cell?
Help to insulate the long axon and is formed by lipids
What are the main structures of an egg cell?
Cell membrane
Haploid nucleus
Cytoplasm
What is the role of the cell membrane and how does is it specialized in an egg cell?
Allows substances in and out of the egg cell and changes after fertilisation to prevent anymore sperm from entering
What is the role of the cytoplasm in an egg cell?
Contains nutrients to help develop an embryo
Why do egg cells and sperm cells contain haploid nucleuses?
Holds half the normal amount of chromosomes and contains the cell’s DNA for when fertilisation happens
What are the main structures in a sperm cell?
Tail
Haploid Nucleus
Acrasome
Large quantities of mitochondria
What is the function of the acrasome in sperm cells?
The acrasome contains enzymes which are used to digest the egg’s cell membrane and fertilize the egg
What is the reason for larger quantities of mitochondria in sperm cells?
Provides more energy in order to swim towards the egg cell
What is the 1 structure found in ciliated epithelial cells that isn’t common in animal cells?
Cilia
What is the function of cilia on ciliated epithelial cells?
They are small hair-like structure that beat to move mucus and trapped dirt to the nose/mouth
What is the main difference between light microscpes and electron microscopes?
Electron microscopes can achieve a much greater magnification and resolution
What are the four stages of carrying out a microscope practical on onion cells?
- Add drop of water to microscope slide
- Take a very thin piece of tissue from an onion so that light can pass through it
- We then stain the onion sample with iodine so we can see the structures within the onion
- Then lower a cover slip on top of the onion sample and view it through the microscope
What is the function of saliva in digestion?
Contains amylase to digest carbohydrates
What is the function of the stomach in digestion?
Contains hydrochloric acid which kill bacteria and secrete protease enzymes to digest proteins
What is the function of the small intestine in digestion?
Absorption of small molecules into the blood occurs
Which enzyme does salivary glands secrete to digest carbs?
Amylase
Which enzyme does the stomach secrete to digest proteins?
Protease enzymes
What enzyme does the pancreas secrete to digest fats?
Lipase
What are the three stages of enzymes reacting?
- Substrate which is complimentary to active site moves towards active site.
- Substrate combines with active site speeding up reaction
- Two products are made from the substrate which leave the active site
Why are enzymes important during digestion?
They help to break down insoluble substances into soluble substances which can then be digested
What are the four food tests?
Starch
Protein
Glucose
Lipids
What substance is used in a starch food test?
Iodine
What substance is used in a protein food test?
Biuret solution
What substance is used in a glucose/reducing sugars food test?
Benedict’s reagent
What substance is used in a lipids/fats food test?
Ethanol
Describe the only stage of a food test for starch
Add iodine to the sample
Describe the 2 stages of a food test for proteins
- Add potassium hydroxide
- Add biuret to sample
Describe the 2 stages of a food test for glucose/reducing sugars
- Add benedict’s reagent to sample
- Heat gently with a water bath
Describe the 3 stages of a food test for lipids/fats
- Add ethanol to sample
- Shake the sample
- Pour the sample into water
What would a positive result show for a starch food test?
Blue/ black colour change
What would a positive result show for a protein food test?
Purple colour change
What would a positive result show for a glucose/reducing sugars food test?
Substance changes colour
What would a positive result show for a lipids/fats food test?
Milky emulsion
What is calorimetry used for?
It is used to determine the energy content of food
What is diffusion?
The net movement of particles form an area of high concentration to low concentration
What is osmosis?
The net movement of water molecules from a high concentration to a low concentration through a partially-permeable membrane
Why are diffusion and osmosis passive processes?
They require no energy to happen/occur
What happens to cells in dilute solutions (pure water)?
Water moves into cells by osmosis
What happens to cells in solutions with the same concentration as the cytoplasm?
There is no net movement of water in or out of cells
What happens to cells in concentrated solutions (salt)?
Water moves out of the cell by osmosis
What are the three states that plant cells can be in after osmosis?
Turgid
Flaccid
Plasmolyzed
What is active transport?
The movement of particles from a low to high concentration against the concentration gradient
Why is active transport not a passive process?
It requires energy to occur
What is the plant example for active transport?
Root hair cells transport ions against their concentration gradient from soil to the plant
