Topic 1 Flashcards
What do only plant cells have that human cells don’t
Rigid cell wall
Large vacuole
Chloroplast
What does the nucleus contain and what does it do
DNA that controls what he cell does
What is the cytoplasm
Gel-like substance where most chemical reactions happen
What does the cell membrane do
Holds the cell together and controls what goes in and out
What is the mitochondria
Where most of reactions for respiration to take place, which releases energy needed for cells to work
What is the rigid cell wall made of and what does it do
Cellulose and gives support oft the cell
What does the large vacuole contain
Cell sap, weak solution of sugars and salts
What is chloroplast
Where photosynthesis occurs and contains green chlorophyll
What 4 things do both plant and animal cells have
Nucleus
Cytoplasm
Cell membrane
Mitochondria
Where is Chromosomal DNA found in a bacterial cell and what does it do
It is one long circular chromosome that floats in the cytoplasm
Controls cells activities and replication
What are plasmids (in bacterial cells)
Small loops of extra DNA that aren’t part of the chromosome
Contain genes for things like drug resistance
Can be passed between bacteria
What is flagellum (flagella) and what does it do in bacterial cells
Long, hairlike structure that rotates making bacteria move
What is a bacterial cell supported by
Cell wall
Name two types of microscopes
Light
Electron
Structure of DNA
Two strands coiled together in the shape of a double helix
Adenine and
Thymine
Guanine and
Cytosine
DNA Codes for
Proteins
DNA pairs are joined together by
Weak hydrogen bonds
What four people are responsible for the discovery of the structure of DNA
Franklin and Wilkins
Watson And Crick
How did Franklin and Wilkins discover the helical structure of DNA
By directing beams of x-rays onto crystallised DNA
Looked at patterns formed as x-rays bounced off
What did Watson and Crick do
Created a model fitting all together the structure of DNA including the base pairs A-T C-G
How do cells make proteins
By stringing amino acids together in specific orders
What are proteins made by
Ribosomes (organelles)
Describe the process of translation showing how proteins are made
DNA is to big to move out of nucleus which cells need to get the info from to give to ribosome in cell cytoplasm
Does so using MRNA as the messenger (shorter single strand)
DNA strands unzip and used as template to make MRNA, base paring ensuring complementary = TRANSCRIPTION
MRNA molecules move out of nucleus and join ribosome
Amino acids brought to ribosome that match MRNA code by TRNA
Ribsomes stick amino acids together in chain =polypeptide(protein) following order of bases in MRNA =TRANSLATION
What is a mutation
A change in organisms DNA base sequence that could effect sequence of amino acids in protein
Effecting shape and function there changing characteristics of organism
What three things can mutations be
Harmful
Beneficial
Neutral
Enzymes are
Biological catalysts
A benefit and negative of enzymes
They speed up both useful and non useful reactions by increasing temperature
All enzymes are
Proteins
Work inside and outside body
Examples of how enzymes work in and outside of cells
DNA replication
Protein synthesis
Digestion
A substrate is
A molecule that changes in a reaction
For an enzyme to work
The substrate must fit into the active site perfectly
However enzymes have high specificity for their substrate
“Lock and key” mechanism
Three things effecting enzymes
Temperature
PH
Substrate concentration
Optimum PH for enzymes
PH 7
Except pepsin in stomach works best in acidic conditions PH2
What is the human genome project
Thousands of scientist collaborating to find every human gene
25,000
Positives of they an genome project
Medicine and forensic science Predict and prevent diseases New and better medicines Accurate diagnoses Improve forensic science
Negatives oft he human genome project
Not being perfect
Increase stress (knowing susceptible to disease for young age)
Gene-ism (pressure not to have children)
Des criminality by employers and insurers
Describe the process of Genetic engineering
1) useful gene “cut” from chromosome using restriction enzyme
2) enzyme used to cut another chromosome and insert useful gene into another organism (genetically modified organism)
Three benefits of genetic engineering for humans
Reducing vitamin A deficiency -gold rice beta-carotene
Produce human insulin- insulin gene injected into bacteria
Increase crop yeild- GM resistant to herbicides
Long term concerns of Genetic engineering
Reduce biodiversity of weeds and flowers(wildlife)
Not convinced are safe
Fear of transplanted genes getting into environment e.g ‘superweeds’
Mitosis makes new cells for
Growth and repair
Mitosis uses
Human body cells= diploid
One of each mother no father chromosome
Mitosis produces
Two identical cells to original
Mitosis is used in ……… reproduction
Asexual
Describe briefly the process of mitosis
1) cell not dividing, DNA spreads in long strings
2) cell devices and duplicates DNA, copies form x-shaped chromosomes each arm exact duplicate of other
3) line up in centre and cell fibres bull the apart to opposite sides of cell
4) membranes form around each cell becoming nuclei or 2 new cells
5) cytoplasm divides forming two diploid cells
Meiosis uses
Gametes
Half usual number of chromosomes
Ova and sperm
Meiosis is used in ……… reproduction
Sexual
Gametes are
Haploid
When two gametes join together they form the right number of chromosomes which is
Zygote- which are diploid and have the right amount of chromosomes
Three factors of meiosis
1) to make new cell with half number of chromosomes cell divides
2) only in reproductive organs
3) produce 4 haploid nuclei (chromosomes not identical)
Describe the processor of the first division in meiosis
DIVISION 1
1) cell duplicates DNA each arm exact copy of chromosome
2) chromosome pairs lime up centre of cell
3) cell fibres bull apart each cell one copy of each chromosome (M&F)
4) mixture of alleles creates variation in offspring
Describe the process of the second division in meiosis
1) chromosomes reline up in centre of cell and pulled apart
2) 4 haploid gametes each with single set of chromosomes in it
Name three uses of cloning mammals
Storage organs for transplantation
Study lead to greater understanding of embryo, age and age-related illness
Preserve endangered species
Three issues with cloning mammals
‘Reduce gene pool’ fewer alleles in population
Not live as long eg dolly 8 years 1/2 as long as normal
Risks and problems with health
Describe the prices of stem cells
Fertilised egg divides by mitosis to produce bundle of cells
Embryonic stem cells are all the same in embryo (undifferentiated)
Divide to produce more stem cells or different types of specialist cells
Differentiation is
The process of stem cells becoming specialised.
Embryo developes recognisable human body with organs and systems
What is the difference between animal and plant stem cells
Animals look ability to differentiate at young age (adults only in bone marrow, not a versatile to differentiate as from embryos)
Plants never lose ability
Ethical concerns of stem cells
Embryos shouldn’t be used-potential life
Aim of curing patients suffering more important than human life?
Banned in some countries (strict guidelines in uk)
