Unit One: Cells 🧫 Flashcards
What do animal cells contain?
Cytoplasm, a nucleus, a cell membrane, and mitochondrion
What do plant cells contain?
Cytoplasm, a nucleus, a cell membrane, a cell wall (made of cellulose), mitochondria, a permanent vacuole and chloroplasts
What takes place in the cytoplasm?
Chemical reactions.
What does the nucleus contain
Chromosomes
What is the nucleus surrounded by?
The Nuclear membrane
What are the chromosomes inside the nucleus made of?
DNA (DeoxyrboNucleic Acid)
What happens within the mitochondrion?
Chemical reactions/ cell respiration
What is the purpose of the cell wall (plant cells)
Prevent the cell from bursting
What does the vacuole contain?
Cell sap, which stores water.
What’s the purpose of the vacuole?
(When full) makes the cell rigid and provides support to the plant
What do chloroplasts contain?
Chlorophyll (green pigment)
What is the job of chlorphyll?
Traps light and helps the plant produce food
Are bacteria cells single celled?
Yes
Is there a cell membrane surrounding the cytoplasm in bacteria cells?
Yes
Is there a nucleus in bacteria cells?
No
What is inside the circular chromosome inside the cytoplasm?
DNA
What are plasmids?
Small rings of DNA (present in bacteria cells)
What is the cell wall made of (in bacteria cells?)
Not cellulose
What does a bacteria cell contain?
Cytoplasm, A cell wall, chromosomal DNA, plasmid DNA, and a flagellum (not always present)
What’s the unit used to measure cells?
Micrometers
How many micrometers in a cm?
1000 micrometers= 1mm
What’s the equation used to calculate magnification of cells?
Magnification= length of image divided by the actual length of the image
How do you calculate the actual the length of a cell?
Actual length= length of the image divided by the magnification
What level of magnification can electron microscopes get up to?
Up to about 50,000,000x
What are some advantages of electron microscopes?
Higher resolution and very high magnification
What are some disadvantages of electron microscopes?
Specimens must be dead, images aren’t in colour, special training required, extremely expensive
Is the cell membrane selectively permeable?
Yes
How do substances move in and out of cells?
Diffusion
What is diffusion?
The random movement of a substance from where it is in a high concentration to where the concentration is lower
How is the rate of diffusion affected by the concentration gradient?
The larger the concentration gradient, the larger the rate of diffusion
How does temperature affect the rate of diffusion?
Higher temperatures increase kinetic energy therefore increasing the rate of diffusion
How does surface area affect rate of diffusion?
The larger the surface area, the faster diffusion takes place
What are cells?
(Microscopic) Building blocks of living things
What are tissues?
Cells that are similar in function, grouped together to form tissues
What is an organ?
A structure made out of several types of tissue, that carries out a particular function (eg, heart, lungs, a leaf)
What is an organ system?
Groups of organs which co-operate to carry out a particular function (eg, digestive system, cardiovascular system)
What is an organism?
A group of organ systems that make up a complex animal or plant
What are stem cells?
Very simple, undifferentiated cells that continue dividing to produce more stem cells and differentiate into a wide variety of specialised cell types
What are embryonic stem cells?
Stem cells only found in early animal embryos that can form any cell type. They grow rapidly and are easy to culture
What are adult stem cells?
Unspecialised cells only found in certain organs in adults, these can only produce certain types of cells. They are more difficult to grow and culture.
Where are plant stem cells found?
Apical growing points or meristems
What can stem cells treat?
Leukaemia (by transferring bone marrow), to produce new immune cells which can fight disease, to help treat genetic diseases
How is leukaemia treated?
- Chemo and radiotherapy to destroy cancerous cells. 2. The patients bone marrow stops producing new cells. 3. Patient is given a bone marrow transplant. 4. Donor stem cells produce new, healthy cells.
What’s a risk of leukaemia treatment?
Destruction of the person’s white blood cells leaves the person with no immune system, and the stem cells may divide uncontrollably and produce tumours or unwanted cell types
Is the use of embryos (stem cells) be considered murder?
Yes
Who’s human rights are ignored (stem cells)
The embryo
What do some people fear may lead to cloning or designer babies
Use of Stem cells.
