Key concepts in biology Flashcards
How have changes in microscope technology have helped our cell knowledge?
Advances in microscope technology (including electron microscope) have enabled us to see cell structures and organelles with more clarity and detail than in the past and increased our understanding of the role of sub-cellular structures
Magnification calculation?
Magnification = image/actual
Magnification measurements?
- mm
- micrometres
- nanometres
- picometers
1mm = 1000 micrometres
1 micrometre = 1000nm
1nm = 1000pm
1pm = 1x10^-12
Measurements in standard form?
a. mm (10-3)
b. micro (10-6)
c. nano (10-9)
d. pico (10-12)
Animal cell functions and structures
- Nucleus
- Cell membrane
- Mitochondria
- Ribosomes
NUCLEUS - contains genes and controls cell activities. DNA codes for specific proteins to building new cells
CELL MEMBRANE - controls what enters and leaves the cell and separates cells. Also helps hold the cell together
MITOCHONDRIA - where most aerobic respiration reactions occur, releasing energy for cell processes
RIBOSOMES - where translation in protein synthesis occurs, needed to make new proteins
Plant cell functions and structures
- Nucleus
- Cell membrane
- Cell wall
- Chloroplasts
- Mitochondria
- Vacuole
- Ribosomes
NUCLEUS - contains genes and controls cell activities. DNA codes for specific proteins to building new cells
CELL MEMBRANE - controls what enters and leaves the cell and separates cells. Also helps hold the cell together
MITOCHONDRIA - where most aerobic respiration reactions occur, releasing energy for cell processes
RIBOSOMES - where translation in protein synthesis occurs, needed to make new proteins
CELL WALL - cellulose, supports, strengthens and protects cells
CHLOROPLASTS - where light energy is transferred from the sun for photosynthesis which occurs to make food for the plant, contains chlorophyll
VACUOLE - stores cell sap and helps keep the cell turgid (maintains internal pressure)
Demonstrate an understanding of number, size and scale, including the use of estimations and explain when they should be used
Estimations should be done to around 1 significant figure and should be used to check the answer is correct
Describe how specialised cells are adapted to their function
- sperm cells
SPERM CELLS:
- Contain an acrosome (large vesicle or small vacuole, when sperm reaches the egg, the acrosome opens to release enzymes to digest through the jelly coat, eggs outer layer)
- Contain a haploid nucleus (1 copy of chromosomes: gametes fuse in fertilisation to form a diploid zygote, 2 copies of chromosomes)
- Contain a lot of mitochondria at the base of the tail (which release energy from respiration to propel the sperm)
- Contain a flagellum (slender-like structure which propels the sperm whilst swimming)
Describe how specialised cells are adapted to their function
- egg cells
EGG CELLS:
- Contain a haploid nucleus (1 copy of chromosomes: gametes fuse in fertilisation to form a diploid zygote, 2 copies of chromosomes)
- Contain nutrients in the cytoplasm (supplies the growing embryo with energy and raw materials for growth and development)
- Changes in the membrane (the jelly coat) after fertilisation (after the gamete cells fuse, the jelly coat hardens in order to prevent other sperm from fusing with the egg, the jelly coat also protects the ovum)
Describe how specialised cells are adapted to their function
- ciliated epithelial cells
CILIATED EPITHELIAL CELLS:
- Contain cilia line tubes (e.g. trachea and oviduct)
- Cilia (small, slender hair-like structures)
- Contains strands of a substance which can contract causing wavy side to side movement to sweep substances along (e.g. mucus/ova)
- Cells which line structures in the body are called epithelial cells
- If they have cilia, they are called ciliated epithelial cells
Explain how the structure of bacteria is related to its function
- chromosomal DNA
- plasmid DNA
- cell membrane
- ribosomes
- flagella
- cytoplasm
CELL MEMBRANE - controls what enters and leaves the cell and separates cells. Also helps hold the cell together
RIBOSOMES - where translation in protein synthesis occurs, needed to make new proteins
CHROMOSOMAL DNA - lies free in the cytoplasm (no nucleus), carries most bacterial genes and controls most activities e.g. replication
PLASMID DNA - additional genes controlling a few activities, passed between bacteria
Flagella - rotates like a propeller to help the bacteria move (in liquid)
Which solutions do the following tests need?
- starch
- proteins
- fats
- reducing sugar
Starch - iodine solution
Proteins - biuret solution
Fats - ethanol
Reducing sugar - benedict solution
Explain how the energy contained in food can be measured using calorimetry
You measure the energy released from the food when the food is burning with a calorimeter. If there is a lot of energy released, the temperature of the water will rise however, not all of the released energy would contribute to the final temperature as some may be lost into the surrounding environment and some could be lost to the stirrer in the apparatus
Test for starch
Test for proteins
