Flashcards

Additional Science:Biology

bneale English 33 cards

Cards in this deck (33)

1Genetic Engineering -In genetic engineering (also called genetic modification) a gene form one organism is inserted in the DNA of another organism. The inserted gene then makes its protein in the genetically modified (GM) organism.
2Advantages of GE -Making human insulin using GM bacteria is quicker and cheaper than producing it any other way.So more people with diabetes can be treated. -'golden rice' is a GM plant that contains genes from other plants that increases the production of beta-carotene. Beta-carotene makes vitamin A. It could prevent illness caused by lack of vitamin A in people who mainly eat rice.Disadvantages of GE
-A few diabetic people react badly to this insulin and need different form.
-Golden rice seed costs more than normal rice seed, so the poorest people can't afford to grow it.
3Mitosis -There are two types of cell division. Mitosis is the cell division that happens in body cells. A body cell is any cell except those that produce gametes (sex cells)Things to remember
1) Mi-to-sis makes TWO cells
2)MiTosis makes idenTical cells
3)Diploid means double (two sets of) chromosomes.
4Asexual reproduction -Asexual reproduction is the production of new organisms without fertilisation, such as when: -bacteria split in two to make more bacteria -plants make new plantlets that split off from the parent plant to grow on their own
5Fertilisation Fertilisation takes place during sexual reproduction. Fertilisation is when a male gamete (sex cell) combines with a female gamete to produce zygote.Meiosis
Meiosis is the second type of cell division. It happens when a diploid cell divides to produce haploid gametes (sex cell, such as sperm and egg cells).
6Advantages of cloning -If the animal that is cloned has good features, all of its offspring will have the same good featuresDisadvantages of cloning
-It is more difficult to clone a mammal than a plant. It may take many attempts before a healthy cloned mammals is born, and each attempt costs money
-Cloned mammals may suffer more health problems than usual, which may cause them to die early.
-Any genetic defect in the parent will be passed on to the offspring.
7Enzymes Enzymes are biological catalysts. Enzymes control reactions in the body. A catalyst changes the rate of a reaction but remains unchanged at the end of the reaction. -Each enzyme is specific for its substrate, which means it only works with that substrate.
8Enzyme Some enzyme-controlled reactions occur inside cells to join substrate molecules together. For example : -DNA replication -One enzyme catalyses the splitting part (unzipping) of the two DNA strands. -A different enzyme catalyses the joining of bases to make new strands.Each reaction during transcription and translation in protein synthesis is controlled by a different enzyme.
9Active site -The shape of the active site matches the shape of the substrate molecule and holds them close together so bonds can form between them to make the product. - If the product molecule doesn't fit the active site well it is released from the enzyme.
10Enzyme action 'Lock and Key' -The 'lock and key' hypothesis describes the way that the substrate fits like a 'key' into the active site (the 'lock').-This hypothesis explains why enzymes are specific (only to work with one substrate), because only a substrate with the right shape can fit into the active site. The hypothesis also explains how enzyme activity changes in different conditions.
11Enzyme action Temperature -At lower temperatures, molecules move more slowly. So substrate molecules take longer to fit into and react in the active site. -At the optimum temperature the enzyme is working at its fastest rate.-Higher temperature cause the active site to change shape, so it can't hold the substrate as tightly and the reaction goes more slowly.
-At very high temperatures the active site breaks up and the enzyme is denatured.
12Exercise -When you exercise, your heart rate and breathing rate increase. The harder you exercise, the more these rates increase. -Heart rate can be measured by taking your pulse. Breathing rate is measured by counting the number of breaths a minute.
13Why heart rate and breathing rate change -During exercise,, muscle cells are respiring faster. This means that they need more oxygen and glucose, and release more carbon dioxide: -A faster heart rate means that the blood is being pumped faster around the body. The blood takes oxygen and glucose to cells faster and removes carbon dioxide faster. -A faster breathing ate means that oxygen can be taken into the body at a aster rate and carbon dioxide can be released faster.
14Anaerobic respiration -Anaerobic respiration is the release of energy from glucose without using oxygen. This produces lactic acid. Anaerobic respiration can be shown using a word equation: glucose-->lactic acid (+energy)
15Advantages of anaerobic respiration -Anaerobic respiration is useful for muscle cells because it can release energy to allow muscles to contract when the heart and lungs cannot deliver oxygen and glucose fast enough for aerobic respiration.Disadvantages of anaerobic respiration
-Anaerobic respiration releases much less energy from each molecule of glucose than aerobic respiration.
-Lactic acid is not removed from the body.. It builds up in muscle and blood, and must be broken down after exercise.
16EPOC -Anyone who exercises hard will find that their heart and breathing rate take a while to return to their normal resting heart rate when exercise has ended. This is known as post-exercise oxygen consumption (EPOC)
17Limiting factors -Low temp. dim light and low carbon dioxide concentration all limit the rate of photosynthesis. -We can measure the effect of these factors on the rate of photosynthesis by measuring the rate at which oxygen is given off by a piece of pondweed.You can use this apparatus to investigate the effect of:
-temp. using warm and cold water baths
-light intensity using bright and dim lights
-carbon dioxide concentration by adding different amounts of sodium hydrogen carbonate to the water.
18Water transport -Water and substances dissolved in the water are transported around plants in veins. Veins contain tissues called xylem and phloem.
19Transpiration -Transpiration is the evaporation of water form the inside leaves out into the air. It causes water to move up the plant from the roots.1)Evaporation of water vapour from leaves (transpiration)
2)Draws water out of leaf cells and xylem
3)Draws water up the xylem from the roots
4)Causes water to enter the roots by osmosis
20Type of transport 1)Diffusion-Substances move down their concentration gradient -no energy needed 2)Active transport-Substances move up (or against) their concentration gradient -need energy so substances can move 3)Osmosis-diffusion of water molecules
21Organisms and the environment 1)Collecting animals -stone lid shelters trap from sun and rain -hole in ground -container Known as pitfall trap and is used for collecting small ground-living animals.Sweep net or pond net=for collecting larger animals
Sweep through the grass and bushes or through water in pond or stream
22Pooter=for collecting animals smaller than the inlet tube -inlet tube -mouth piece -a suck on mouthpiece draws the animals in through the inlet tube -net to stop animals getting into your mouth.
23Quadrats A quadrat is a square frame of a particular size (e.g 50cm) A quadrat can be used to sample plants or animals that don't move much. To get good results: -each quadrat should be placed randomly in the sample area -count the number of organisms, or estimate the area covered by the organism, in each quadrat -repeat the measurement in several quadrats -calculate an average measurement for one quadrat
24Fossils and evolution -Fossils are the preserved traces or remains of organisms that lived thousands or million of years ago. The fossil record in rocks gives us evidence of what the living organisms were like and how they changed over time. Change over time is called evolution.1)Fossils do not always form->fossils only form if conditions in the ground are suitable (e.g. not too acidic)
2)Soft tissue decays->hard tissue may fossilise but soft tissue usually decay too quickly to fossilise
3)Many fossils are yet to be found->we only find fossils where we can dig them up-many are much deeper than the ground already is
25Growth and development in plants -Plant growth includes cell division just behind the shoot tip, and cell elongation (the cells get longer) further away from the tip of the shoot. Cells at the tip of the shoot are all the same. They can develop into any kind of cell in a plant.Growth and development of animals
-Animals grow in a different way from plants. As the animal gets older, most of the cells in their body differentiate into specialised cells, such as muscle, bone or nerve cells.
Cell division:very rapid for growth --> slow for repairs
Cell differentiation:not differentiated-->most differentiated
All the cells in an embryo are stem cells. This means they can produce almost any kind of cell. Only a few cells in a child or adult's body are undifferentiated stem cells. These stem cells help repair damaged tissue
26Blood -Blood is made of four main parts:plasma, red blood cells, white blood cells and platelets.Blood plasma
Plasma is the liquid part of blood:
-It carries the blood cells through the blood vessels
-It contains many dissolved substances, such as carbon dioxide and glucose
27White blood cells White blood cells are larger than red blood cells, and they have a nucleus. All types of white blood cells are part of the immune system, which attacks pathogens in the body.
28Platelets Platelets are fragments of larger cells. They have no nucleus. Their function is to cause blood to clot when a blood vessel has been damaged. The clot blocks the wound and prevents pathogens getting into the blood.Red blood cells
Red blood cells contain haemoglobin which carries oxygen. The biconcave of a red blood cell means it has a larger surface area. This makes it easier for oxygen to diffuse into and out of the cell. The cell has no nucleus. This means the cell has room for more haemoglobin to carry more oxygen
29The heart -Cells are grouped into tissues are grouped into organs. The heart is an organ than contains tissues such as heart muscle and tendons. Heart muscle is formed from heart muscle cells
30The circulatory system -An organ system is a group of organs that work together t carry out a particular function in the body. The circulatory system is an organ system that consists of the heart, the blood vessels and the blood. Its function is to transport materials around the body.
31The digestive system -There are many organs in the digestive system. These organs work together to digest food and allow food molecules to be absorbed into the body.1)Mouth
-Food enters the body
-Chewing breaks up food and mixes it with enzymes to start digestion.
2)Oesophagus
-Carries food from mouth to stomach
3)Liver
-Produces bile, which helps in digestion of fats in small intestine
-converts food molecules absorbed from small intestine into other molecules
4)Gall bladder
-Where bile form liver is stored until needed in the small intestine
5)Small intestine
-Digestion of food by enzymes completed
-Food molecules are absorbed into the blood
-Water absorbed from digested food
6)Pancreas
-Produces enzymes that are released into the small intestine
7)Large intestine
-Some water absorbed
-Undigested food forms faeces that pass out of body through anus
32Probiotics and prebiotics -Functional foods are foods that claim to make you healthier when you eat them. -Probiotic foods contain 'friendly' bacteria that are usually either Bifidobacteria or LactobacillusPrebiotics
Prebiotic foods contain high levels of oligosaccharides
33Villi The surface of the small intestine is adapted for efficient absorption of the soluble products of digestion.-Large capillary network carries absorbed molecules rapidly away-maintains steep concentration gradient for diffusion into villus
-Millions of villi increase surface area for diffusion of soluble products of digestions
-Surface formed from a single layer of cells- allows molecules to diffuse rapidly into villi