Topic 1 - Cell Biology Flashcards
nucleus function
Controls and regulates the activity of the cell and contains DNA
Cytoplasm function
-Gel like substance where Chemical reactions happen and holds everything in place
-Contains enzymes that control these rewctions
Cell surface membrane function
Keeps everything in the cell, and keeps unwanted things out. Let’s in nutrients.
Ribosomes function
Makes proteins
Mitochondria function
-Where most of the reactions for aerobic respiration take place
Organelles in an animal cell
-Nucleus
-Cell surface membrane
-Ribosomes
-Mitochondria
-Cytoplasm
Organelles in plant cells
-Vacuoles
-Chloroplasts (Made of chlorophyll)
-Cell wall (made of cellulose)
Chloroplasts function
Used for photosynthesis
Contains chlorophyll which absorbs light needed for photosynthesis
Cell wall function
Supports the cell and makes it strong
Made of cellulose
Vacuole function
Contains a cell sap which is a weak solution of sugar and salts
How are phloem and xylem cells specialised
-Transport substances such as food and water around plants
-To form these tubes the cells are long and joined end to end
-Xylem cells are hollow in the centre
-phloem cells have few sub cellular structure so things can flow through the,
White blood cell
-Fights bacteria, viruses and other invaders
-Destroy harmful substances and prevent illness
Root hair cells
-On the surface of plant roots which grow into long hairs that stick out into the soil
-Gives the plant a big surface area for absorbing water and mineral ions from the soil
What are adult stem cells
-We have stem cells in our body (e.g. bone marrow)
-Can only turn into certain cell types, such as blood crlls
Embryonic stem cells
-Come from a developing embryo (usually one that has been discarded after IVF)
-Can turn into any kind of cell at all
Arguments against stem cell research
-Drugs given to women to stimulate eggs are dangerous
-Embryonic stem cells are unstable and cause tumours
-Even at 3 days embryos are considered living things
-Organisms given stem cell therapy often develop problems
-Embryos are created purely for research
For stem cell research
-Diverts resources to treatments that really work
-Offers treatment to many incurable diseases
-No waiting lists for organ transplant ion
-Less lab animals and money will be wasted and money will be wasted testing new drugs
-Will offer a cure for many diseases such as diabetes and cancer
-Donated cells are identical so there are no problems with rejection
-A cell at 3 days is not a living thing as it only contains 150 cells
-Damaged or dead can grown and replaced
-Curing existing patients ailments is more important than the life of the embryo
What is diffusion
The net movement of particles from an area of high concentration to low concentration
How does concentration affect diffusion
Particles travel faster when there is a higher concentration
How does temperature affect diffusion
Particles travel faster when hotter
How does surface area affect diffusion
The larger surface area the greater rate of diffusion
Partially permeable meaning
somethings can get in/out
Diffusion - alveoli and blood
-Carbon dioxide is made during respiration which goes into the blood, which carries it to the lungs where it diffuses into the alveoli
-Oxygen is brought in through the lungs and diffuses into the blood which carries it to be used in cells in the body for respiration
Diffusion between skin and small blood vessel
-Oxygen diffuses through the thin skin into a small blood vessel. The oxygen then diffuses into the cells
-Carbon dioxide that is made in the cells goes into the blood and diffuses out the skin
Epithelial Tissue
-Epithelial cells are specialised because they need to be thin when lining your organs, so when activity happens there isn’t any friction.
-They line both external and internal parts of the body
-Can line organs and in tubes around the body (e.g. small intestine and stomach)
-Also found as part of the skin
Muscular tissues
-Soft tissue that makes muscles in animals that must be able to shorten or contact to make the body
Glandular tissue
Secretes things such as hormones. They make up glands for things such as sweat they rope-like and lumpy.
What is a tissue
A group of similar cells that carry out a specific function.
What are eukaryotic cells
They are complex cells and include all animal and plant cells
What are prokaryotic cells
Smaller and simpler cells (e.g. bacteria)
Features of a prokaryotic cell (bacteria)
-Cell membrane
-Cell wall
-No nucleus but a single strand of DNA that floats in the cytoplasm
-May contain small rings of DNA called plasmids
-Don’t have chloroplasts or mitochondria
-Cytoplasm
Features of an electron microscope
-Higher resolution
-Higher magnification
-Allows us to see smaller things in more detail such as internal structure of mitochondria and chloroplasts or ribosomes and plasmids
Formula for magnification
Magnification = image size / regular size
Difference between micrometers and millimetres
from micrometers to millimetres divide by 1000
How to prepare slides
-Add water in middle of a clean slide and cut up an onion and separate it into layers
-Use tweezers to pull off epidermal tissue from the bottom of one of the layers
-Place it into the water on the slide and add a drop of iodine solution which is a stain and highlights the object in a cell by adding a colour
-Place a cover slip on top by standing it upright on the slide next to the water and tilt and lower it so it covers the specimen
How to use the light microscope to look at your slide
-Clip it onto the stage and select the lowest powered objective lense
-Use the coarse adjustment knob to move it up to just below the objective lens.
-Look down the eyepiece and use the coarse adjustment knob until it is roughly in focus
-Ajust the focus with the fine adjustment knob until you get a clear image of the slide
What to do once you’ve viewed your onion with the microscope
-Draw what you see using a pencil with a sharp point and make sure it takes up at least half of the space available and that it is drawn with clean, unbroken lines
-Don’t include colouring or shading
-sub cellular structures should be drawn in proportion
-Out a title and write down the magnification, then label features