Biology

What is mitochondria?

Uses oxygen and sugars such as glucose to release energy via respiration.

What is a cell membrane?

The outer of a cell, has the function of controlling substances that can pass through or into the cell and substances that may harm the cell therefore are denied access.

What is a cell wall

Made of cellulose fibres, it acts as a protective wall located outside of the cell membrane. The function of the organelle is to maintain a strong rigid structure of the plant cell, this is key so then it can absorb extra nutrients. The strength of this organelle is why plant cells don’t burst when absorbing excess water.

What is a nucleus?

Known as the brain of the cell, the nucleus controls the movement and activities the cell does.

What are ribosomes

These are one of the smallest organelles of a cell, and their perform what is known as protein synthesis meaning the production of proteins within cells.

What is a permanent vacuole

A vast organelle that holds the cell sap in plants, and additionally absorbs extra nutrients for the plant to feed on.

What is cytoplasm?

A jelly like organelle that is where chemical reactions take place within a cell.

What are chloroplasts?

Only being in plants cells, these are made from a green substance called chlorophyll which is what captures light for the function chloroplasts being the sight of photosynthesis- meaning the build up of light.

What is the significance of a DNA loop in a prokaryotic cell?

Instead of having a nucleus, like eukaryotic cells, a freely floating DNA loop is what holds a prokaryotic cell’s genetic information.

What are plasmids?

Small rings in prokaryotic cells, that contain extra DNA such as genes?

What is a flagellum?

A vast organelle in a tail like structure, that protrudes out of a cell and helps provide movement for the cell.

What are specialized cells?

Cells that are adaptated to perform their percific function.

What is the function of a red blood cell?

To transport oxygen around the body, as it binds to the iron protein pigment haemoglobin (making oxyhaemoglobin)

What is the function of a sperm cell?

To fertilize the egg cell, creating an organism.

What is the function of a nerve cell?

To transfer electronic signals around the body, via the nervous system.

What is the function of a root hair cell?

Helps transport nutrients, such as water, to the plant from the soil

What is the function of a xylem cell?

Pushes water up the plant.

What is the purpose of capillaries having 1 cell thick walls?

So then it creates a shorter diffusion pathway.

What direction do veins carry blood?

Away from the body to the heart.

What direction do arteries carry blood?

Back towards the heart?

What are the coronary arteries?

Arteries that are located on the exterior of the heart and are the hearts own supply of oxygenated blood.

What id diagnosed with CHD (Coronary heart disease)?

When fatty deposite builds up in the coranary arteries, restricting blood flow to the heart.

What is the heart?

A vital organ, that cats as a double muscular pump that contracts and relaxes to pump oxygenated blood around the body.

Describe the flow of blood through the heart?

Starting as deoxygenated blood it enters the heart via the vena cava and proceeds to flow through the right atrium into the right ventricle, passing though the tricuspid valve to prevent the blackfow of blood on the left side of the heart. Then the right ventricle contracts, pumping blood out of the heart via the pulmonary artery, passing the septum to prevent deoxygenated and oxygenated blood interacting and the pulmonary valve to prevent the backflow of blood, then towards the lungs. Gaseous exchange then occurs, with carbon dioxide diffusing out of the bloodstream and into villi, and oxygen diffusing into the blood streamfrom the villi. The blood is now oxygenated, so it returns to the heart via the pulmonary vein into the left atrium on the right side of the heart, then passes through the bicuspid valve and into the left ventricle. The left ventricle then contracts, pumping oxygented blood at a high pressure past the septum- to not allow deoxygentaed and oxygenated blood to interact- then out of the heart via the aortric valve and the aorta. Oxygenated blood tranvels through the body, allowing cells to respire, then becomes deoxygenated and returns to the heart for this process to be repeated.

What is the first stage of the cell cycle called?

The growth stage

What happens to chromosomes during the growth/replication stage?

21 chromosomes duplicate, resulting in 42 chromosomes grouped into 21 pairs.

What is the second stage of the cell cycle?

Mitosis.

What occurs to the nucleus during mitosis?

The nucleus divides into two nuclei.

How do chromosomes behave during mitosis?

They line up along the middle of the nucleus and then separate to opposite sides via the pulling of celluous fibers until the nucleus begins to pinch inwards and form another nucleus.

What is the third stage of the cell cycle?

Cytokinesis.

What is the result of cytokinesis?

Two genetically identical cells, each containing 21 individual chromosomes.

What is the role of the cell membrane during cytokinesis?

It separates the two nuclei into two distinct cells by pinching inwards.

How many chromosomes does each new cell contain after cytokinesis?

21 individual chromosomes.

What is the significance of the chromosome duplication in the growth stage?

It ensures that each daughter cell receives an identical set of chromosomes.

What process causes the nucleus to split during mitosis?

The pushing of chromosome groups against the nucleus walls. Which is done by celluous fibers latching onto one of the chromosomes in each pair, and pulling them apart.

What is the function of the stomach?

Has the function of breaking down larger food molecules into smaller food molecules so then they can be absorbed into the blood stream.

What is the esophagus?

A muscular tube that food enters after being chewed by teeth in the mouth. When food enters this muscular tube, it contracts and relaxes to forcefully push food into the stomach.

Describe the lining of the small intestine?

It has a large surface area of villi, that allow food molecules to enter the bloodstream via diffusing through each villous into a network of cappilaries.

What are villi?

Finger-like projections that line the interior of the small intestine. They have the function to allow food molecules to enter the bloodstream, via diffusing into a network of cappillaries.

What is the function of the large intestine?

Absorbs water in the digestion process.

What is the function of the rectum?

Stores feces until a suitable time comes to deploy feces via the anus.

Explain the adaptation of villi being a large surface area?

Allows more food molecules to enter the blood stream via diffusion.

What is the purpose of villi having 1 cell thick walls?

Allows a shorter diffusion pathway for food molecules when entering the blood stream.

What is an adaptation of villi?

Allows villi to maintain a constant balanced concentration of food molecules within the blood stream.

What is the primary function of the gallbladder?

To store and release bile during digestion.

What is bile?

A digestive juice that is very alkaline and contains all digestive enzymes.

How does bile help in digestion?

Bile cancels out stomach acid and emulsifies fats, increasing the surface area for lipid digestion.

What does lipase do?

Lipase breaks down lipids into fatty acids and glycerol.

What is the role of amylase?

Amylase breaks down carbohydrates into sugars, specifically glucose.

What does protease do?

Protease breaks down protein molecules into amino acids.

What is the lock and key model in enzyme activity?

It describes how enzymes catalyze reactions by binding to specific substrates at their active sites.

What happens when an enzyme denatures?

The active site changes shape, preventing the substrate from binding and halting the reaction.

What conditions can lead to enzyme denaturation?

Extreme pH levels, high temperatures, or very low temperatures.

What is the function of the kidneys?

To filter substances like urea, mineral ions, and excess water from the blood.

What is urea?

A waste product formed from the breakdown of amino acids.

What are nephrons?

Microscopic structures in the kidneys that filter substances from the blood.

What is the structure of a nephron?

It consists of a tubule and a network of capillaries for filtration and selective reabsorption.

What is selective reabsorption?

The process where essential nutrients like amino acids and glucose are absorbed back into the bloodstream from the tubule.

Blood is filtered into the Bowman's capsule, allowing substances to diffuse into the nephron.

What occurs in the nephron

What happens to urea after selective reabsorption?

It is left in the tubule, collected in the collecting duct, and eventually forms urine.

What is the role of the collecting duct in the kidneys?

To transport urea from all nephrons to form urine for excretion.

What is the significance of the alkaline nature of bile?

It neutralizes stomach acid, creating optimal pH levels for enzyme activity.

What is the effect of high temperatures on enzymes?

High temperatures can denature enzymes, altering their active sites.

What are the main waste products filtered by the kidneys?

Urea, excess water, and mineral ions.

How do essential nutrients return to the bloodstream?

They diffuse back into the blood from the nephron tubules during selective reabsorption.

What is the primary waste product of protein metabolism?

Urea.

What is the function of the tubule in a nephron?

To absorb molecules that can diffuse, such as urea, water, and nutrients.

What is Benedict's test used for?

To test for the presence of reducing sugars, such as glucose.

What is the result of a positive Benedict's test?

A color change to yellow, orange, or brick-red depending on the amount of reducing sugar present. Yellow indicates a low concentration, orange indicates a medium concentration, and brick-red indicates a high concentration of reducing sugars.

What is the purpose of the iodine test?

To detect the presence of starch in a food sample.

What indicates a positive iodine test?

A color change to blue-black.

What is the Biuret test used for?

To test for the presence of proteins.

What indicates a positive Biuret test?

A color change from blue to purple.

What is the ethanol test used for?

To test for the presence of lipids.

What indicates presence of lipids?

The cloudy white solution changing grey after shaking vigorously.

What part of the nephron is responsible for filtering blood?

The glomerulus.

What is the function of Bowman's capsule?

It surrounds the glomerulus and collects the filtrate from blood filtration.

What happens during reabsorption in the nephron?

Essential nutrients and water are absorbed back into the bloodstream.

What is the role of the loop of Henle?

To concentrate urine by reabsorbing water and ions.

What is the primary function of the collecting duct?

To transport urine from nephrons to the renal pelvis for excretion.

What is the significance of the renal corpuscle?

It is where blood filtration occurs, consisting of the glomerulus and Bowman's capsule.

What reagent is used to test for starch?

Iodine, which appears orange before the test.

How do you prepare a food sample for starch testing?

Crush the food sample, add water, and stir using a stirring rod. Then add in your reagent.

What happens to the iodine solution if starch is present?

The solution turns from orange to blue-black.

Do you use a water bath when testing for startch?

No a water bath is not necessary as it will disrupt the iodine complex.

What indicates the absence of starch in a solution?

No color change occurs; the solution remains orange.

What reagent is used to test for lipids?

Ethanol, which is a clear liquid.

How is a food sample prepared for lipid testing?

Mix the food sample with water in a test tube and stir. Then add in ethonal.

What color change indicates the presence of lipids in a sample?

The solution turns from cloudy white to grey after shaking.

What is the first step in lipid testing?

Add ethanol to the mixture of food sample and water.

What defines the independent variable in practical testing?

The characteristic that changes between each object being tested.

What defines the dependent variable in practical testing?

The characteristic that stays the same between each object that is tested.

What are control variables in a practical test?

Control variables are any factors that are kept constant. Keeping them ensures a fair test between objects being tested. These are what can be controlled by the conductor of the practical test.

What are the names of the blood vessels that are connected to the heart?

Vena cava (vein), Aorta (artery), Pulmonary artery and Pulmonary vein.

Where does the pulmonary artery transport blood to?

Deoxygenated blood from the heart to the lungs to be oxygenated.

Where does the vena cava transport blood to?

Deoxygenated blood from the body to the heart.

Where does the pulmonary vein transport blood to?

Oxygenated blood from the lungs to the heart.

Where does the aorta transport blood to?

Oxygenated blood from the heart to body cells for respiration to occur.

What are the four chambers of the heart?

On the right side there is the left atrium and the left ventricle, and on the left side their is the right ventricle and the right atrium.

What is the function of the right atrium?

To receive deoxygenated blood from the systematic circuit.