Prelim Revision Flashcards
What is a unicellular organism?
An organism with one single cell
What is a multicellular organism?
An organism made up of many cells
What does the nucleus do?
Controls cell activities and contains genetic material (DNA)
What does the cell membrane do? What is it made of?
Controls what enters and exits the cell, made of phospholipids and plasmids, selectively permeable
What does the cell wall do?
Support and shape, prevents plant cells from bursting
What is the cell wall made of? (plant and other cells)
Cellulose in plant cells, other substances in other cells like fungal and bacterial
What does the vacuole do?
Stores the cell sap, helps to support the cell
What do chloroplasts do?
Contains chlorophyll, site of photosynthesis
What do mitochondria do?
Site of aerobic respiration, and ATP production
What to ribosomes do?
Site of protein synthesis
What is every living organism made of?
Cells (unicellular or multicellular)
What do animal cells contain?
Cell membrane, cytoplasm, nucleus, ribosome, mitochondria
What do plant cells contain?
Cell wall, cell membrane, nucleus, cytoplasm, vacuole, ribosomes, mitochondria, chloroplasts (in green plant cells)
What do fungal cells contain?
Cell wall, cell membrane, vacuole, nucleus, ribosomes, mitochondria, cytoplasm
What do bacterial cells contain?
Plasmid, cell membrane, cytoplasm, cell wall, ribosome
What is aerobic respiration?
The release of energy from food by a cell using oxygen
What is the cytoplasm?
Site of chemical reactions
What is DNA?
Substance found in chromosomes that carries the genetic code
What is photosynthesis?
Process carried out by green plants to make their own food using light energy
What is the cell membrane made of?
Phospholipids and protein
What is passive transport?
The movement of molecules from a high concentration to a low concentration, does not require additional energy
What are some examples of passive transport?
Diffusion and osmosis
What is diffusion?
The movement of substances from a high concentration to a lower concentration
What are some examples of substances that enter most cells by diffusion?
Oxygen, glucose, amino acids
What are some examples of substances that leave most cells by diffusion?
Carbon dioxide, Urea
Why is diffusion important?
Helps provide the cell with raw materials and helps to remove waste products
What is osmosis?
The movement of water molecules from a region of high water concentration to a region of low water concentration
What would happen to an animal cell placed in a solution with a higher water concentration than that inside the cell?
Burst
What would happen to an animal cell placed in a solution with a lower water concentration than that inside the cell?
Shrink
What would happen to a plant cell placed in a solution with a higher water concentration than that inside the cell?
Turgid
What would happen to a plant cell placed in a solution with a lower water concentration than that inside the cell?
Plasmolysed
What is active transport?
The movement of molecules from a region of low concentration to a higher concentration, requiring additional energy (ATP)
What is the chromosome complement of a cell?
The number and type of chromosomes it contains
What would it mean if the chromosome complement was diploid?
That their nuclei have two matching sets of chromosomes
What is replication?
The process by which DNA copies itself
What is a replicated chromosome called?
A chromatid
What happens during mitosis?
Each chromosome is replicated, the nucleus of a diploid parent cell divides to produce two daughter cells (genetically identical to the parent calls)
What is the sequence of events during mitosis?
- Chromosomes replicate and become visible as pairs of chromatids
- The chromosomes line up along the equator of the cell
- Their chromatids are pulled to opposite poles by spindle fibres to form two new nuclei
- The cell cytoplasm then splits between the new nuclei to form two daughter cells
What are chromosomes made up of?
Genes
What is a single DNA molecule called?
A double stranded helix
What does each strand of DNA carry?
A chain of molecules called bases
What are the four different types of bases?
Adenine, Thymine, Guanine, and Cytosine, these bases make up the genetic code
What does the base sequence of a specific gene determine?
The amino acid sequence in the specific protein to be assembled
Where are proteins assembled?
At the ribosomes in the cell cytoplasm
What is messenger RNA (mRNA)?
A molecule that carries a complementary copy of the code from the DNA in the nucleus to a ribosome
What does the shape of a protein affect?
The function
What are the functions of proteins?
Structural, Enzymes, Hormones, Antibodies and Receptors
What do structural proteins do?
Make up cell structures such as membranes
What do enzymes do?
Function as biological catalysts and are made up by all living cells, they speed up chemical reactions and are unchanged in the process
What do hormones do?
Act as chemical messengers between cells and travel in body fluids such as blood
What are antibodies?
Protein molecules that are involved in body defences
What are receptors?
Found in cell membranes, recognise specific substances
What is the substance an enzyme acts on called?
The substrate
What is the active site of an enzyme?
Where they bind to substrate molecules
What does it mean that enzymes are specific?
The shape of the active site only fits with the shape of the complementary substrate, lock and key
What conditions does an enzyme work best in?
Optimum
What can extremes in temperature or pH do to the enzyme? How will this affect the enzyme?
Change its molecular shape, known as denaturation, this will affect the rate of the reaction
How can genetic information be transferred?
Naturally or Artificially
What are some natural methods of genetic transfer?
Fertilisation in plants and animals
