Flashcards
Biology Mock (Topics 1, 2, 3, 4)
Flashcards do conjunto (46)
- 1What is the difference between prokaryotes and eukaryotes?Eukaryotic cells are complex, which include animal and plant cells. Prokaryotic cells are smaller and simpler (i.e. bacteria)
- 2What are all living things made out of?Cells
- 3Name the 5 main subcellular structures in an animal cell, and state what they do.Nucleus - contains genetic material that controls the activities of the cell
Cytoplasm - substance in which most chemical reactions happen, helped by enzymes
Cell membrane - holds the cell together and controls what goes in and out
Mitochondria - where most reactions for aerobic respiration take place
Ribosomes - where proteins are made for the cell out of amino acids - 4Name the 3 plant-exclusive subcellular structures in a plant cell and state what they do.Cell wall - cellulose wall that strengthens the cell
Permanent vacuole - contains cell sap, a weak solution of sugar and salts
Chloroplasts - where photosynthesis occurs, which uses a green substance called chlorophyll to absorb light and make energy for the plant - 5What type of organism are bacteria?A prokaryote (or single-celled organism)
- 6What is the formula for magnification?magnification = image size / real size
- 7What is the process by which cells change to become specialised?Differentiation
- 8How is a root hair cell specialised for it's function?It has a large surface area, allowing it to absorb water and mineral ions from the soil
- 9How does the structure of the sperm cell help it perform its function?Its long tail lets it 'swim' through the uterus, and the many mitochondria in the cell provide it with the energy needed. the enzymes in the top of its head help it digest through the cell membrane
- 10What part of the cell contains genetic material?The nucleus
- 11What is the name given to coiled up length of DNA molecules in a double helix shape?Chromosomes
- 12How many pairs of chromosomes does a human cell have?23
- 13What are the two phases of cell division?Interphase and the mitotic phase
- 14Describe what happens in the interphase.The cell grows physically larger, duplicates organelles (namely ribosomes and mitochondria). Then, it synthesises a complete copy of the DNA, and grows more and organises its contents ready for mitosis.
- 15Describe what happens during mitosis.The chromosomes line up at the centre of the cell, and fibres pull them apart. The two arms of each chromosome go to the opposite ends of the cell. Membranes form around each set of chromosomes, which form the nuclei of the new cells. Lastly, the cytoplasm and cell membrane divide.
- 16What are the two new cells produced after mitosis called?Daughter cells
- 17How do prokaryotic cells replicate?Binary fission
- 18Describe what happens during binary fission.The circular DNA and plasmids replicate, and the cell gets bigger. The circular DNS strands move to opposite poles of the cell, cytoplasm begins to divide, and new cell walls begin to form. The cytoplasm eventually divides and two daughter cells are produced.
- 19What are the best conditions for cells to replicate?Warm environments with lots of nutrients.
- 20How do you calculate the number of bacteria in a population?Put the given time into minutes, and divide by the mean division time. Then, find the value of 2 to the power of the result.
- 21Where can stem cells be found?Human embryos, the umbilical cord, and bone marrow.
- 22Name some reasons people are against embryonic stem cell research.-- Each embryo could potentially be a human life
-- - 23Which part of the plant is where growth occurs?The meristem
- 24What is one useful purpose of using meristems to produce identical plants?To prevent rare species being wiped out, or to reproduce plants that have features desirable to farmers
- 25What is diffusion?The movement of particles from an area of high concentration to an area of lower concentration, down a concentration gradient
- 26Where does diffusion happen?Diffusion happens in solutions and gases
- 27What is a concentration gradient?The concentration gradient is the difference in concentration of a dissolved substance between a region of high to low concentration
- 28What factors increase the rate of diffusion?*Higher temperatures
*Higher concentration gradients
*Heavier molecules diffuse slower
* Diffusion distance - 29Can molecules diffuse across a cell membrane?Yes, small molecules such as oxygen, glucose, amino acids, and water can diffuse through a cell membrane
- 30When does diffusion stop?When all molecules in the solution/gas have reached equilibrium (are evenly spread out)
- 31What is osmosis?Osmosis is the diffusion of water molecules across a partially permeable membrane
- 32Which direction do these water molecules travel across the membrane?Both ways
- 33What is active transport?Active transport is the movement of molecules across a concentration gradient, but the wrong way -- molecules move from an area of low concentration to an area of high concentration
- 34What does active transport need?Energy, in the form of protein (specifically ATP - Adenosine triphosphate)
- 35Where do some examples of active transport happen?* Root hair cells on the root of plants use active transport to absorb nutrients
* In the gut, glucose, amino acids and other nutrients are absorbed into the blood using active transport - 36How do you calculate surface area and volume, and put them into a ratio?Surface area: WIDTH x HEIGHT
Volume: WIDTH x HEIGHT x DEPTH
Put it into a ratio: SURFACE AREA:VOLUME - 37When does differentiation occur?During the development of a multicellular organism (conception to birth)
- 38What are groups of similar cells known as?Tissues
- 39Name three cell tissues* Muscular tissue
* Glandular tissue
* Epithelial tissue
* Nervous tissue - 40What are tissues organised into? Name someOrgans:
* Stomach
* Brain
* Intestines
* Liver
* Kidneys - 41What are organs organised into? Name someOrgan systems:
* Glands
* Intestinal system
* Circulatory system
* Nervous system - 42What controls chemical reactions in an organism?Enzymes
- 43What is a catalyst?A substance which increases the speed of a reaction without being changed or used up in the reaction.
- 44What are enzymes made out of?Large proteins (chains of amino acids)
- 45What is an active site?The area of an enzyme where the substrate fits into it and speeds up a reaction. The active site is complementary to the shape of the enzyme.
- 46How are enzymes denatured?* By heating them to more than 40 degrees Celsius
* By raising the pH to a lot above or below 7 (neutral)