Cells Flashcards
What is the function of the cell membrane?
Outer membrane of cell that controls movement in and out of the cell it’s also double layered
What is the function of the cytoplasm?
The liquid medium where chemical reactions take place
What is the function of the nucleus?
Controls cell activity separated from the cytoplasm by nuclear membrane contains genetic material
What is the function of the mitochondria?
Releases energy through respiration breaking down fats and carbs, controls level of water and other materials in cell. Found in the cytoplasm. The chemical reactions are aerobic respiration take place within the mitochondria. Cells like muscle cells need lots of energy and so have more mitochondria in their cytoplasm.
What is a cellulose cell wall
Most commonly found in plant cells and bacteria plant cells. Cell walls are composed made of cellulose supports and protects cells.
What is the permanent vacuole?
Contains cell sap, helps plants maintain shape.
What is the function of the chloroplasts?
Contain green chlorophyll to absorb light energy, where photosynthesis takes place
What are bacteria?
Microscopic single celled organisms. They are neither plant nor animal cell because their cell structure is so different.
What is the function of the circular chromosome?
DNA that controls cell activity. Circular and free in cytoplasm.
Function of plasmids?
Tiny circular sections of extra DNA
The function of the cell wall
Maintains cell shape and structure.
Cytoplasm
Location of chemical reactions
What is the flagellum?
Whip like structure used to move/swim
What happens when plants aren’t watered
They wilt as the vacuole needs watered and without can’t hold its shape
2 structures in bacterial cells that contain DNA
Genetic material
Ring of plasmid
Why do we use a coverslip
To hold the specimen in place and to stop the specimen drying out
How do u estimate the length of one cell
Diameter of field of view over estimated number of cells that cross the diameter
How do you find the total magnification
Multiplying the power of the ocular lens by objective lens
Metre millimetre and micrometer
M
Mm
um
Magnification
Size of image over size of object
Magnification triangle
I am
How do u magnify when it’s given with its actual length
Measure the cell, convert it to micrometers and divide by the actual length
What does red blood cells do and what do they contain
Delivers oxygen to the cells and contains haemoglobin
What do nerve cells do and what do they contain
Designed to stimulate other cells on the body in order to communicate, and making sense of touch possible and warning the body of dangers
What do skin cells do and what do they contain
A protective barrier that keeps nutrients and water inside the body and protects against pathogens and excessive water loss
What are cells
They come in all shapes and sizes they are the smallest unit that can carry out all seven life processes
What are tissues
Formed from groups of similar cells there cells work together to do a particular job
What are organs
Made from a group of different tissues which all work together to do a particular job.
Describe an organ system
Made from a group of different organs which all work together to do a particular job
Describe an organism
An independent living thing
Examples of cells
Muscle, palisade cell
Examples of tissue
Muscle, tissue
Examples of organs
Lungs heart
Examples of organ system
Respiratory, circulatory system
Examples of organisms
Plant, animal
What do cells in living organisms need to be able to obtain
Oxygen and glucose for respiration nitrate ions for plants for growth. They also need to be able to remove waste eg waste
What happens in unicellular organisms
The exchange takes place through the cell surface membrane. They have specialised exchange surfaces and in more complex organisms there is transport system that links to the specialised exchange surface eg gills in fish
What is diffusion
Net movement of gas or dissolved molecules from an area of high concentration to an area of low concentration until equilibrium is reached
Small organisms…
Gain all their requirements through their body surface and remove waste the same way
Larger organisms…
Do not have enough surface area to meet the metabolic needs of the large number of cells that are not in direct contact with the surrounding environment
What equilibrium is reached
There is no net movement and it’s passive so it does not require energy because substances are moving down the concentration gradient.
What effects the rate of diffusion
Temperature = higher Temp more kinetic energy so faster diffusion
Concentration gradient=bigger concentration difference the steeper the concentration gradient faster diffusion.
Surface area= the larger the surface area the faster diffusion will happen
Explain efficient diffusion
Maintained concentration gradient
Large surface area
Thin and short diffusion distance
What are stem cells two important abilities
They can divide into more stem cells and they can differentiate into a wide variety of specialised cell types
What are embryonic stem cells
Undifferentiated cells capable of continuing cell devisions and of developing into almost all the cell types of an adult organism
What are adult stem cells
Undifferentiated cells capable of cell divisions and of giving rise to a limited range of cells within a tissue type eg blood stem cells give rise to red and white cells and platelets only
What can stem cells be used to treat
Incurable diseases
Where do stem cells come from
Embryos
What ethical issue does this cause
Murder abortion
What is therapeutic cloning and what are the advantages and disadvantages
Creating cloned adult cells to translate back into the patient
