Cells Flashcards
What is the nucleus involved in?
- controls normal cell activities
- responsible for cell reproduction
- repairs worn-out parts of the cell
What does the nucelus contain?
- instructions for protein synthesis
- the organism’s genetic material
What happens when a cell does not have a nucleus?
- the cell will have a shorter lifespan e.g. red blood cell
- reproduction is not possible
What takes place in the cytoplasm?
- most life processes take place
- chemical reactions take place e.g. metabolism
What is the job of the cell surface membrane?
- regulates the movement of substances in and out of the cell
What cannot enter the cell and why?
- large molecules such as proteins, carbohydrates and lipids
- they cannot enter as they are too large to enter the cell
- things that do not dissolve in lipids (fats) e.g. water
- charged molecules e.g. ions
What can enter the cell and why?
- small molecules such as oxygen and carbon dioxide
- they are small enough to easily diffuse into the cell
- things that dissolve in lipids (fats)
How do substances that dissolve in water enter the cell?
- proteins become channels for small molecules that dissolve in water
What is the cell surface membrane made up of?
- it is made up of lipids and proteins
What is the purpose of the cell wall?
- to provide shape and support to the cell
Why can all things pass through the cell wall?
- it is fully permeable
What are some characteristics of the cell wall?
- they are rigid and distinct
- they enclose the whole cell
- they are made up of cellulose
What do chloroplasts do?
- to trap light
- to combine carbon dioxide and water to make food
What are chloroplasts?
- they are the site of photosynthesis
What does the mitochondrion do?
- it is involved in cellular respiration
- they are also involved in the release of energy from food
What does the mitochondria synthesize?
- adenosine triphosphate (atp)
What is the endoplasmic reticulum?
- it is an extension of nuclear membrane into cytoplasm
- it is a network of membranes
- there are two types of endoplasmic reticulum (ER)
- rough and smooth ER
What does the smooth ER do?
- synthesizes lipids, cholesterol and steroids
- converts harmful substances into harmless ones
- this process is called detoxification
What does the rough ER have and what does it do?
- it has ribosomes
- ribosomes attached produce proteins for secretion outside the cell
What do free lying ribosomes do?
- they produce proteins for use inside the cell
What is the golgi body?
- series/stack of membrane-bound sacs
What does the golgi body do?
- modifies products from the ER and secretes them (secretory vesicles)
What is the difference between the vacuole of an plant cell and that of an animal cell?
- animal cells have many small vacuoles that are usually not permanent
- plant cells have a large, central vacuole
Why is there a difference in the vacuole of a plant cell and animal cell?
- animals are able to replenish their water supply regularly
- plants need to go long periods of time without water so their vacuoles need to store more water for long periods of time
What is the function of a root hair cell?
- absorbing water and mineral salts from soil
What is the adaptation in the root hair cell and why is it useful?
- narrow and long protrusion
- to increase surface area of cell
What is the result of the adaptation of the root hair cell?
- efficient absorption of water and mineral salts from soil
If adaptation of root hair cell was missing?
- plant wilts
- plant becomes unhealthy and susceptible to diseases
What is the function of red blood cell?
- transport oxygen from lungs to all parts of the body
What is the adaptation of the red blood cell?
- circular
- biconcave
- contains hemoglobin
- does not have a nucleus
What is the result of adaptation of red blood cell?
- diffusion rate of oxygen in and out of cell increases
- more oxygen carried per cell
- increases surface area to volume ratio
What would happen is the adaptation of the red blood cell was missing
- lack of oxygen in cells
- cellular respiration affected
Phrases associated with each structure
- nucleus: double membrane, contains many enzymes
- cell membrane: single membrane, partially permeable, transport
- mitochondria: double membrane, respiration, contains many enzymes
- chloroplasts: double membrane, pigmented, photosynthesis, contains many enzymes
- rough endoplasmic reticulum: single membrane, ribosomes, protein synthesis
- cell wall: non living, permeable, support
- large central vacuole: support, cell sap, storage, single membrane
- smooth endoplasmic reticulum: single membrane, lipid synthesis
- red blood cell: pigmented, transport
- xylem vessel: non living, transport, support
- root hair cell: absorption
