Unit 1 Flashcards
list the structures found in a typical animal cell
- cell membrane
- cytoplasm
- nucleus
- mitochondria
- ribosomes
list the structures found in a typical plant cell
- cell wall
- cell membrane
- cytoplasm
- nucleus
- mitochondria
- ribosomes
- chloroplasts
- vacuole
list the structures found in a typical fungal cell
- cell wall
- cell membrane
- cytoplasm
- nucleus
- mitochondria
- ribosomes
list the structures found in a typical bacterial cell
- cell wall
- cell membrane
- cytoplasm
- ribosomes
- chromosomal DNA
- plasmid DNA
what is the role of cytoplasm?
to be the place where chemical reactions happen
what is the role of the cell membrane?
keeps the cell together and provides a barrier to what enters and exits the cell
what is the role of the nucleus?
contains cell DNA and controls all the events in the cell
what is the role of mitochondria?
release chemical energy from rood (respiration)
what is the role of ribosomes?
to make proteins
what is the role of the cell wall?
to provide structure to the cell
what is the role of chloroplasts?
to carry out photosynthesis
what is the role of vacuoles?
to contain sap
how are the walls of bacteria and fungi different to the cell wall of plants?
they are not made of cellulose
what are plasmids?
small circular sections of DNA
what is the cell membrane made of?
phospholipids and proteins
the cell membrane is selectively permeable, what does that mean?
it allows some but not all substances across it and chooses which substances can enter and exit the cell
what is passive transport?
movement of substances down a concentration gradient ( does not require energy)
what is diffusion?
movement of molecules down a concentration gradient
list 3 substances that can diffuse in and out of a cell
- glucose
- carbon dioxide
- oxygen
- amino acids
- urea
what is osmosis?
the movement of molecules from a high water concentration to a lower water concentration through a selectively permeable membrane
when they absorb too much water what happens to animal cell?
bursts
when they absorb too much water what happens to plant cell?
becomes turgid
when they do not contain enough water what happens to a plant cell?
becomes plasmolysed
when they do not contain enough water what happens to a plant cell?
shrinks
why does active transport require energy?
for membrane proteins to move molecules or ions against the concentration gradient
give an example of active transport
sodium and potassium in nerve cells
or
iodine in seaweed
what is mitosis?
cell division which produces 2 cells with the same number of chromosomes as the original cell
describe the stages of mitosis
- each chromosome replicates to form 2 identical chromotids and the nuclear membrane begins to break down
- chromosomes line up along equator and spindle fibres join on to them
- spindle fibres pull chromotids apart to opposite polls of the cell
- nuclear membranes reform and cytoplasm divides
what is a diploid cell?
a cell with 2 sets of chromosomes
what is a haploid?
a cell with 1 sets of chromosome
why do organisms need mitosis?
to make new cells for growth and repair
what do you need to grow cells in a lab?
- aseptic techniques
- broth or agar
- control oxygen, temperature and pH
describe the structure of DNA
a double stranded helix held together by complementary base pairs
list the 4 bases found in DNA
- adenine
- thymine
- cytosine
- guanine
what are the pairings of bases in DNA?
adenine + thymine
cytosine + guanine
why is the base sequence of DNA important?
so it makes the correct sequence of amino acids to produce protein
what does messenger RNA do?
it carries a complementary copy of the code from DNA in the nucleus to a ribosome where proteins are assembled from amino acids
why do proteins have different shapes and function?
they have different sequences of amino acids
list 5 functions of proteins
provide structure enzymes hormones antibodies receptors
what do enzymes do?
they speed up reactions in a cell and are unchanged in the process
which part of the enzyme interacts with the substrate?
active site
what is a substrate?
a substance the fits into the active side of an enzyme
give an example of an enzyme that takes part in a degradation reaction
pepsin
lipase
amylase
catalase
why do enzymes have optimum conditions?
they need conditions which provide the right enzyme shape
name 2 conditions that can change protein shape
temperature and pH
what is the name given to a protein when its shape is permanently changed by high temperature?
denatured
how can DNA be transferred naturally between cells?
bacterial plasmids or viruses
list the 4 stages of genetic engineering
- identify and extract required gene
- insert gene into plasmid
- insert plasmid into host cell
- grow modified cell
what is respiration?
production of energy from glucose
what controls the reactions in respiration?
enzymes
what is the energy from sugar used to make?
ATP
how is ATP made?
respiration
give the equation for 2 different types of anaerobic respiration
glucose = lactic acid + ATP
glucose = Carbon dioxide + ethanol + ATP
what is ATP used for?
provides energy for cellular activities such as cell contraction, cell division, protein synthesis and nerve impulses
what does anaerobic respiration produce?
lactic acid and ATP
what does fermentation produce?
alcohol, carbon dioxide and ATP
where in a cell does aerobic respiration take place?
begins in the cytoplasm and is completed in the mitochondria
where in a cell does fermentation take place?
cytoplasm
which types of cell have a high number of mitochondria?
a cell that requires a lot of energy - muscle, sperm, neurons, etc
