Topic 1: Cell Biology Flashcards
What are cells?
Basic building blocks of all living organisms
What are tissues?
Group of cells that work together to perform a specific role
What are organs?
Group of tissues that work together to perform specific roles
What are organ systems?
Group of organs that work together to perform specific roles
What is a neuron cell?
A cell that doesn’t replace itself
What is the function of the mitochondria?
Site of aerobic respiration
What is the function of the nucleus?
Control’s cell activities and contains genetic information
What is the function of the cell membrane?
Controls which substance enter and leave cell
What is the function of ribosome?
Protein Synthesis
What is the function of the cytoplasm?
Fluid that fills cell where chemical reactions take place
What is the function of the chloroplast?
Where photosynthesis takes place , Contains chlorophyll
What is the function of chlorophyll?
Green pigment which absorbs light and acts out photosynthesis found in cell organelle, chloroplast
What is the function of the cell wall?
Gives cell structure + maintains shape
What is the function of the permanent vacuole?
Helps maintain shape + maintains cell turgidity
Describe the Onion Experiment
1) Pipette used to drop one drop of water on microscope slide
2) Cut a piece of thin onion skin and separate layer
3) Peel a paper thin layer of epidermal tissue and place on the drop of water with forceps making sure its flat
4) Put two drops of iodine on the tissue
5) Carefully lower a coverslip, using forceps if needed
6) Soak excess water with paper towel
7) Put slide on microscope stage and observe
Name the parts of a bacteria
- Slime Capsule
- Cell Wall
- Flagella
- Plasmids
- Cell Membrane
- Ribosomes
- Single Chromosome (Nucleoid)
What are eukaryotes?
- Animals, Plants, Fungi
- Normally multicellular
- Genetic material stored in nucleus
What are prokaryotes?
- Bacteria
- Unicellular
- Genetic material not stored in nucleus
- No membrane- bound organelles
Where can bacteria be found?
- Can be found anywhere (food, water, air, humans)
- Can survive freezing temp. and hostile environments
How can bacteria be grown?
- Grown at maximum 25°C in schools
> Won’t grow as fast
> Decrease development of pathogenic bacteria - Grown at 37°C in labs
> Matches body temp.
> Better for investigation
What are red blood cells and how are they adapted?
- Carry oxygen around body
- Doesn’t have nucleus
- Large SA
- Bi-concave shape which absorbs more O2
- Haemoglobin which binds to O2
What are sperm cells and how are they adapted?
- Fertilise egg cell
- Has tail to swim
- Lots of mitochondria for energy
- Contain enzymes which break outer shell of egg
- Contains 1/2 of genetic material
What are nerve cells and how are they adapted?
- Pass sensory impulses from a receptor to an effector
- Dendrites to form connections with neutrons
- Long ocon to carry impulse to target
What are muscle cells and how are they adapted?
- To contract and retract
- Lots of mitochondria for energy
- Work together in groups
What are leaf cells and how are they adapted?
- Carry out photosynthesis
- Packed with chloroplast which contain chlorophyll to absorb light
- Regularly shaped
- Closely packed cell
What are root hair cells and how are they adapted?
- To absorb nutrients and water
- Large SA to increase rate of absorption
- Large Vacuole to control water entry
- Lots of mitochondria for active transport
What is diffusion?
Random movement of particles from an area of high to low concentration
What are some ways to increase rate of diffusion?
- High Concentration Gradient
- Temperature
- Increase SA of membrane
- Diffusion distance
How do you maintain concentration gradient?
Good blood supply
Why can’t some particles diffuse?
Large particles are too large and membrane prevents them.
What is osmosis?
Movement of water from an area of high to low concentration across a partially permeable membrane
If there are more water particles then solute particles, describe the solution
Dilute
High Water Potential
If there are less water particles then solute particles, describe the solution
Concentrated
Low Water Potential
What is active transport?
Movement of a substance against a concentration gradient using energy (ATP) which comes from respiration
What is a hypotonic solution?
Lower solute concentration than inside cell
What is an isotonic solution?
Solute concentration same inside and outside cell
What is a hypertonic solution?
Higher solute concentration than inside the cell
Describe the key Osmosis practical step-by-step
1) Use a cork borer to cut 5 potato cylinders of same diameter
2) Trim the cylinders so they are all the same length
3) Measure length and mass of each cylinder
4) Measure 20cm cubed of distilled water in the first boiling tube and label. Repeat with salt solutions of 0.5 M, 1 M, 1.5 M and 2 M.
5) Add one cylinder to each making sure you know which cylinder goes in which
6) Record the lengths and mass in relation to the solubility they are in with a table
7) Leave cylinders for a set time before removing the cylinders and drying with a paper towel
8) Re-measure length and mass and record measurements on table
9) Calculate change and percentage change
10) Plot graph of results
Why do cells divide?
- Replace dead / damaged cells (repair of tissues)
- Growth
- Asexual Reproduction
What is the difference between sexual and asexual reproduction?
- Asexual reproduction produces genetically identical clones
- Sexual reproduction has two parents
- Sexual reproduction has the fusion of gametes
What are the stages of the cell cycle?
Resting Phase - Not dividing, not replicating, most common phase
Cell Growth Phase (G1 Phase) - Number of organelles increase for growth, gets bigger, replicates all organelles except nucleus
Replication Phase (S or DNA replication phase) - 46 chromosomes are copied (in human cells), enough DNA for 2 identical nuclei
Cell Growth Phase 2 (G2 Phase) - Cells prepare for mitosis
Mitosis - Copies of chromosomes separate, nucleus divides
Why are checkpoints needed in cell cycle?
Ensure nothing goes wrong between and at each phase e.g. damage, mutation
What does cell cycle by mitosis produce?
Two new cells that are genetically identical to each other and to the parent cell
What are genes?
Basic unit of inheritance, codes for a characteristic / protein, found in chromosomes
How many chromosomes do humans have?
46 (haploid) , 23 pairs (diploid)
How are chromosomes paired?
In homologous pairs which have the same gene, but different versions of them
Described the 23rd pair in terms of gender
X-Y : Male
X-X : Female
Not homologous
What are chromosones?
Large molecule of DNA found in nucleus
Describe characteristics of the DNA Model
- Double Helix Structure
- Double Stranded
- Contains Genetic Code
- Biological Polymer
How many sets of chromosomes do body and sex cells have?
Sex - 1 set
Body - 2 sets
What does DNA stand for?
Deoxyribonucleic Acid
Describe how DNA is prepared for mitosis
Long, thin strands which just before the cell divides become shorter, thicker, more visible and condense before duplicating The two chromosomes are joined at the centromere.
What are stem cells?
Undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type and from which certain other cell can arise from differentiation
What are some sources of stem cells?
- Embryos
- Bone Marrow
What are the types of stem cell?
Totipotent - Give rise to any other cell type
Pluripotent - Give rise to every cell except umbilical cord, fetus
Multipotent- Give rise to some cell types
Unipotent - Give rise to one cell type
What is plasticity?
Where adult stem cells are manipulated to produce many different cell types
