Session 1 - Exam 1 Flashcards
What is a cell?
What do they do?
A cell is a building block of life, it is the smallest unit of life, it is made up of oxygen, carbon, hydrogen, and nitrogen. Cells provide structure and function for all living things. There are many complex chemical reactions occurring within a cell and there are many different types of cells.
Often do cells reproduce? Why do they reproduce?
Cells reproduce every 7 to 24 hours in order to replace sick and dead cells, as well as to help an organism grow.
How can you tell if something is living?
MRS GREN
Movement, respiration, sensitivity, growth, reproduction, excretion, nutrients.
Also MR SHENG
Metabolism, Reproduction, Sensitivity, Homeostasis, Excretion, Nutrition, and Growth.
Define the parts of MR SHENG.
Metabolism: sum total of all chemical reactions that occur inside a cell/organism through which energy and basic components are provided.
Reproduction: production of offspring, can be sexual or asexual.
Sensitivity: respond to internal and external stimuli.
Homeostasis: maintain a stable internal environment.
Excretion: removal of waste products.
Nutrition: exchange materials with environment and obtain energy.
Growth: move and change shape and size.
What are Prokaryotes?
Prokaryotes are uni-cellular organisms without a nucleus, e.g. bacteria, archaea.
What are Eukaryotes?
Eukaryotes can be unicellular or multicellular organisms that have a nucleus and their cells contain membrane bound organelles. E.g. Protista, Fungi, Plants, and Animals
What are genes?
Genes contain complex specified instructions for chemical reactions to sustain cellular function (life).
Why are animal cells different from plant cells?
Animal cells do not have cell walls, you can tell because they are more irregularly shaped.
What does it mean for a cell to be typical?
If a cell is typical it has one nucleus and all the correct numbers of the other organelles inside the cell. Not all cells are typical, some fuse together and therefore have multiple nuclei.
What is the Surface Area to Volume ratio?
The surface area to volume ratio outlines how cells need to produce chemical energy (via metabolism) to function and survive which requires material/resource exchange with the environment. Having a larger surface area (rate of material exchange) and a smaller volume (rate of metabolism) allows an organism to meet metabolic requirements. If metabolic rate exceeds rate of exchange than the organism could die. Growing cells will divide and remain small to maintain the SA:V ratio suitable for survival (larger ratio and more efficient material exchange).
What is a Stem Cell?
Stem cells are unspecialised cells that generate specialised cells which make up the organs and tissues of an organism. E..g muscle cells, blood cells, etc. Under the right conditions a stem cell will divide to form daughter cells.
What is Cell Theory?
Cell theory is that cells form tissues, tissues from organs, organs form organ systems, and organ
systems form an organism.
What is a light microscope? Advantages and disadvantages?
A light microscope uses a series of glass lenses to magnify an image, light is focused through the condenser (light below the slide), through the slide, up through objective lens and to the eyepiece lens (uses visible light waves). Advantages: cheap, portable, colour images, different stains can highlight different features, and you can use live materials. Disadvantages: materials have to be thin and transparent, low resolution, and maximum magnification is 1000x to 1500x.
What makes electron microscopes different from light microscopes? What are the two types of electron microscopes? List advantages and disadvantages.
Electron microscopes use a beam of electrons instead of light. There are transmission (going through) electron microscopes, where a 0.08 micrometre slice of material is cut with a diamond knife, stained with heavy metals, and an electron beam is fired through. The parts stained with heavy metals do not allow electrons through and appear dark. The image is projected onto a screen. There are also scanning (surface) electron microscopes where a 3D object is covered with a thin layer of gold which reflects electrons and it forms an image by detecting the reflected electrons and projects the image onto the screen. Advantages: high resolution, high magnifications (200,000x), and SEM can produce 3D images. Disadvantages: expensive, large, requires highly toxic chemicals, time consuming, requires skill, produces black and white images (but colour can be added with a computer), materials must be dead.
What are the units of conversion for magnification?
1 mm = 1000 micrometres
1 cm = 10000 micrometres
1 m = 1 000 000 micrometres
What is the formula (three equations) for magnification?
What do the three variables stand for?
M = I / A
I = M x A
A = I / M
M = magnification
A = actual size
I = image size (size on the paper)
What does it mean for bacteria to be Gram-positive or Gram-negative? Why is this important?
Gram was a person who invented a stain that will come out red/pink (negative) or blue/purple (positive). It indicates the differences in cell wall structure of prokaryotes. Gram-negative bacteria have a thin middle layer (cell wall/peptidoglycan) and Gram-positive bacteria have a thicker middle layer. This is important because knowing this about bacteria can help with treatment because there is different, more effective, treatment for different structures.
What is the protective structure of a prokaryote?
Prokaryotes have 3 layer protective structures: cell membrane (innermost layer), cell wall (peptidoglycan - middle layer), and the slime capsule (glycocalyx - outermost layer).
What are the shapes of bacteria? What are they called?
Cocci = spherical
Bacilli = rod shaped
Vibrios = comma shaped
Spirochaetes = corkscrew shaped
Spirilla = spiral shaped
Coccobacillus = if it looks both rod shaped and spherical.
What are multi-loped nuclei?
Nucleus (nuclei) with multiple parts/lobes.
What do hormones do?
Hormones start and stop every single chemical reactions all according to instruction sets from DNA.
What is ATP? Why would a cell contain large numbers of mitochondria?
ATP stands for Adenosine Triphosphate and is the usable form of energy for cells. Highly energetic cells would contain large numbers of mitochondria because mitochondria produce ATP.
What is glycogen?
Sugar molecules stored in the cell.
What are the types of stem cells?
Totipotent: can differentiate into any cell type.
Pluripotent: can differentiate into any cell you except placental (the placenta is an organ in the uterus) and chorionic (also part of placenta).
Multipotent: adult stem cells which only generate a limited number of cell types based on their tissue of origin.
What is a vacuole and what is its role in both plant and animal cells?
A vacuole is a membrane-bound cell organelle in cytoplasm. In animal cells it helps isolated waste products. In plant cells it is storage but also maintains turgor pressure (helps the cell keep its shape and structure - prevents wilting and bursting) and it can occupy up to 90% of a plant cell.
What does it mean to be polar or non-polar?
If something is polar it is different at each end, often involving positive and negative charge. If it is polar it does not have the above qualities (charges, etc ). Things that are polar can attract and repel each other.
