Topic 1 Flashcards
Are animal and plant cells eukaryotic or prokaryotic?
Eukaryotic
Are bacterial cells eukaryotic or prokaryotic?
Prokaryotic
- What type of cell is shown in the diagram below?
- What key feature allows you to identify the cell below?
- Name the different parts of the cell.
- Bacterial cell
- The genetic material is not enclosed in a nucleus
Name the different parts of the animal cell below
Name the different parts of the plant cell below
Which cells are the smallest out of bacterial cells, animal cells and plant cells?
Bacterial cells
Match the following prefixes to the corresponding standard form.
- What is a plasmid?
- In which type of cells are plasmids found?
- A plasmid is a ring of DNA
- Plasmids are found in bacterial cells
Give the functions of the following cell parts:
a) Ribosomes
b) Mitochondria
c) Cell membrane
d) Nucleus
a) Ribosomes: Protein synthesis
b) Mitochondria: Where respiration happens
c) Cell membrane: Controls what goes in and out of the cell
d) Nucleus: Controls cells activity (where DNA is kept)
Give the functions of the following cell parts:
a) Cell wall
b) Vacuole
c) Chloroplasts
d) Cytoplasm
a) Cell wall: Strengthens the cell
b) Vacuole: Contains cell sap (water, salts and sugars)
c) Chloroplasts: Where photosynthesis happens
d) Cytoplasm: Where chemical reactions occur
What is the main molecule that makes up cell walls?
Cellulose
Name three cell parts that are found in plant cells but not found in animal cells.
- Cell wall
- Chloroplasts
- Vacuole
Name the following specialised animal cells and explain how they are adapted for their particular function
a) Sperm cell: Long tail and streamline to help swim to the egg. Lots of mitochondria for energy. Enzymes in head to help digest into the egg
b) Nerve cell: Long with branched connections to form a network with other nerve cells
c) Muscle cell: Long and contain lots of mitochondria to release energy for contraction
Name the following specialised plant cells and explain how they are adapted to their particular function
a) Root hair cell: Large surface area for absorbing water and minerals. Note: no chloroplasts as unable to photosynthesise underground.
b) Xylem cell: Hollow cells that allow water and mineral ions to be transported.
c) Phloem cell: Not hollow, but have few sub-cellular parts to allow substances to flow through them
What is ‘differentiation’ ?
The process by which a cell becomes specialised
Animal cells differentiate at any early stage. How is this different to plant cells?
Many types of plant cells retain the ability to differentiate throughout life
In mature animals, what is the main purpose of cell division?
For repair and replacement of cells
- Why is an electron microscope better than a light microscope?
- Why have electron microscopes been useful for understanding cell structure?
- Better magnification, better resolution.
- Cells can be seen in much finer detail, therefore scientists now know more about sub-cellular structures.
What equation links magnification, size of image and size of real object.
magnification=(size of image)/(size of real object)
The development of what piece of equipment has led to a better understanding of sub-cellular parts?
Electron microscope
Describe the stages of mitosis
- Cell grows and increases the number of sub-cellular structures (e.g. ribosomes and mitochondria)
- DNA replicates to form two copies of each chromosome.
- One set of chromosome is pulled to each end of the cell and the nucleus divides.
- The cytoplasm and cell membranes divide to form two identical cells.
Why is cell division by mitosis important?
For growth and development
How is the DNA arranged within a nucleus?
Within chromosomes
What is a stem cell?
An undifferentiated cell that is capable of becoming a variety of other cells.
What are the two main places where human stem cells are found?
- Embryos
- Adult bone marrow
Why are embryonic stem cells more useful than stem cells from adult bone marrow?
Embryonic stem cells are able to differentiate into a greater variety of cells.
Which type of stem cells are used to make blood cells and many other types of cells in an adult human?
Stem cells from bone marrow
Where are stem cells found in plants?
In the meristem tissue
Name two conditions that stem cells can be used to treat
- Diabetes
- Paralysis
By what process to substances move in and out of cells along a concentration gradient?
Diffusion
What is diffusion?
The spreading out of particles from an area of high concentration to an area of low concentration.
Give two examples of where diffusion takes place in the body
Examples include:
- Diffusion of oxygen from lungs into the blood
- Diffusion of carbon dioxide from blood plasma into lungs
- Diffusion of urea from cells into the blood plasma
Name three factors that affect the rate of diffusion
- Concentration gradient (difference in concentrations)
- Temperature
- Surface area of the membrane
What two things increase the effectiveness of an exchange surface in plants?
- Large surface area
- Thin membrane
Do single-celled organisms have a relatively small or large surface area to volume ratio?
Large surface area to volume ratio
Explain how the alveoli in the lungs are adapted for gas exchange
- Large surface area
- Thin membrane
- Close to efficient blood supply
- Moist lining
- Ventilated (air moves in and out)
Why do multicellular organisms need exchange surfaces?
They have a relatively small surface area to volume ratio so need exchange surfaces to increase the surface area for diffusion of substances.
Describe how fish gills are adapted for exchanging oxygen and carbon dioxide
- Gill filaments create a large surface area
- Gill filaments have lamellae which increase surface area more.
- Lamellae have lots of blood capillaries
- Thin surface layer
- Large concentration gradient maintained
Describe how small intestine is adapted for exchanging materials
- Covered in millions of villi
- Villi provide a large surface area
- Villi have a single layer of surface cells
- Close network of capillaries
Describe how the plant root is adapted for exchanging materials
- Root covered in millions of tiny hairs
- Root hair cells have a large surface area
- Root hair cells have a thin surface
Describe how the leaf is adapted for exchanging materials
- Leaves are flat to increase the surface area
- Tiny holes (stomata) allows gases to diffuse in and out.
- Air spaces in leaf expose more surface of the cells
By what process does water move across cell membranes?
Osmosis
What is osmosis?
The diffusion of water from a dilute solution (where there are more water particles) to a concentrated solution (where there are fewer water particles) through a partially permeable membrane.
What is Active Transport?
The movement of substances from a lower concentration (more dilute) to a higher concentration (more concentrated)
Where does the energy for Active Transport come from?
Respiration
Give an example of active transport in plant roots
Mineral ions move from the soil into plant root hairs by active transport.
Describe how molecules can move by active transport in the blood
Digested food molecules (e.g. sugar) can move from lower concentrations in the gut to higher concentrations in the blood
