Cells and Control Flashcards
(39 cards)
Mitosis
Mitosis= cell division that happens in body cells
Body cell= any cell except those that produce gametes (sex cells)
Cell that is dividing= called parent cell and two new cells are formed are called daughter cells
Daughter cells = identical to the parent cell , so if the parent cell is diploid the daughter cells will be diploid too .
Mitosis makes two cells
Mitosis makes genetically identical cells
Diploid means double (two sets of) chromosomes
What is mitosis What does mitosis produce What is the cell that is dividing called What are the new cells called Describe these new cells How many cells does mitosis make What does mitosis make What does diploid mean
Stages of Mitosis
IMPAT
interphase Prophase Metaphase Anaphase Telophase
*a cell is interphase most of the time
Interphase = end of interphase chromosomes start to become visible. DNA has already been copied
Prophase=each chromosome consists of two chromatids
Metaphase=nuclear membrane breaks down. Chromosomes line up along the middle of the cell
Anaphase= the chromatids separate and one chromatid from each pair is pulled to each pole of the cell. The chromatids can now be called chromosomes
Telophase= spindle divers disappear and a new nuclear membrane forms round each group off chromosomes.the cell splits into two. This is called cytokinesis
What are the stages of mitosis
What is the cell in most of the time
Describe all the stages
Uncontrollled cell division
Cancer cells are abnormal cells that uncontrollably by by mitosis to form a tumour
Cells stop dividing when growth has finished , except when repair
What are cancer cells
What happened when cells stop dividing
Growth In animals
In animals , a fertilised egg/zygote divided by mitosis to produce genetically identical cells
These cells grow and divide by mitosis
And eventually differentiate into different types of cells to make up a whole organism
Differentiation creates specialised cells adapted to carry out a particular function
Examples of specialised animal cells: Red blood cells Egg and sperm cells Nerve cells Bone cells Smooth muscle cells
What happens in animal growth ?
What happens to the cells ?
What does differentiation create ?
List examples of specialised cells ?
Growth in plants
Plant cells divide by mitosis
After this the cells grow by enlarging
cells elongate= young cells have small vacuoles which take in water by osmosis and enlarge
These cells differentiate into specialised cell types. Most plant cells can continue to grow and differentiate throughout life.
Examples of specialised plant cells: Xylem Mesophyll cells Atoms cells Phloem Root hair cells
How do plant cells divide ? How do the cells grow after this ?
What does elongate mean ?
What happens to the cell after ?
List examples of specialised plant cells.
What does specialised cell mean ?
Why is cell differentiation important ?
Growth and percentile charts
When organisms grow they get bigger . Growth can be measured in different ways
Growth is a permanent increase in size
Percentile charts =can help to show if a child is growing faster or slower than is normal for their age
Babies with mass above 95th line or below 5th line = may not be growing properly
Baby whose mass decreased by two or more percentile Catogries over their first year = may not be growing properly
BMI= measure of a healthy body mass
What is a percentile chart ?
What two ways show a baby may not be growing properly ?
What is BMI?
Stem cells
Cells in an embryo =unspecialised
They divide to produce specialised cells in the body , such as neurones and muscle cells.
Once the cells have differentiated they cannot divide to produce other kinds of cells
Stem cells= cells that can divide to produce many types of cell
three kinds of stem cell:
Embryonic=are taken from embryos at a very early stage of division
Adult= found in differentiated tissue , such as bone or skin. They divide to replace damaged cells
Meristems =plants have these , are found in rapidly growing parts of the plant e.g tips of roots and shoots . These cells can divide to produce any kind of plant cell
All stem cells:
Advantages and risks
Advantages:
Replace faulty cell with healthy cell, so person is well again
Risks:
Stem cells may not stop dividing , and so cause cancer
What are stem cells
What do stem cells produce
What are the 3 kinds of stem cells
Describe them
What are the advantages of using all stem cells ?
What are the risks of using all stem cells ?
Stem cells
Embryonic stem cells
Have many uses including:
Replacing or repairing brain cells to treat people with Parkinson’s disease
Replacing damaged cells in the retina of the eye to treat some kinds of blindness
Growing new tissues in the lab to use for transplants or drug testing
Using stem cells
Advantages :
Easy to extract from embryo
Produce any type of cell
Disadvantages:
Embryo destroyed when cells removed- some people think embryos have a right to life
What are embryonic stem cells ?
What are their uses ?
What are the advantages of using stem cells ?
What are the disadvantages of using stem cells ?
Stem cells
Adult stem cells (from Bone marrow) can only form a limited number off cell types. This can be used for:
Treatment of leukaemia
Potentially growing new tissues that are genetically matched to the patient
Adult stem cells advantages and disadvantages:
Advantages:
No embryo destroyed so not an ethical issue
If taken from the person to be treated , will not cause rejection by their body
Disadvantages:
Produce only a few types of cell
What are adult stem cells ?
Where are they from ?
What can they form ?
Why are they used for ?
What are the advantages of using adult stem cells ?
What are the disadvantages of using adult stem cells ?
Neurones
Stimuli detected by = sensory receptors that she’s impulses along sensory neurones to the central nervous system
Neurones=specialised cells that carry nervous impulses
Three main types of neurones:
Sensory neurone
Motor neurone
Relay neurone
Sensor neurone=carry impulses from the central nervous system
Motor neurone=carry impulses from the central nervous system to the effector organs
Relay neurones =found in the central nervous system
What is a neurone ? What is stimuli ? How are stimuli detected ? What are the three types of neurones ? Describe each of their functions
Neurones
Sensory neurones:structures Skin receptor cells Dendron Axon Cell body Axon Fatty myelin sheath Axon endings
Sensory neurones:function of-structure
Skin receptor cells=dendrites collect impulses from receptor cells
Dendron=carries impulses towards cell body
Axon=carries impulses away from the cell body
Fatty myelin sheath=insulates the neurone
Axon endings=pass impulses to other neurones
What is a sensory neurone ?
What are the structures of a sensory neurones?
What are the function of a sensory neurones ?
Neurones
Motor neurone:structures Nerve endings Myelin sheath Nucleus Dendrite Axon Cytoplasm Cell membrane
Motor neurone: function of structures
Nerve endings=transmits impulse to an Effector , such as muscle or gland
Myelin sheath=a fatty layer that provides electrical insulation around the neurone
Nucleus =
Dendrite=receiving impulses from receptor cells and other neurones
Axon=carries impulses away from the cell body
Cytoplasm =
Cell membrane=
Relay neurone
Function = carry impulses from one part of the central nervous system to another
What s a motor neurone ?
What does it do ?
Wa are the structures ?
What are the functions of these structures ?
What is a relay neurone ?
What is the function of a relay neurone ?
Meiosis
Type of cell division that produces four daughter cells , each with half the number of chromosomes.
Meiosis only happens in gamete -producing cells , producing genetically different haploid gametes
Stages of meisos:
Interphase
- 2 pairs of chromosomes
- before the parent cell divides each chromosome is copied
- chrosmomes joined up
- each daughter cell gets a copy of one chromosome from each pair
- each daughter cell has only one set of chromosomes .haploid daughter cells -not identical -meiosis results in variation
- haploid cells produce by meiosis , have one set of chromosomes
- cells produced by division are always called ‘daughter cells’ even if they eventually turn into sperm cells
What is meiosis?
What are the stages of meiosis?
Describe them
What does haploid mean
What are the cells produced by division called
What if the cells produced turn into sperm cells , what are they called ?
DNA
Dna=genetic material found in the chromosomes in the nuclei of cells
DNA in the cell
Chromosome= consists of a string of genes
Gene=short prince of DNA for a specific protein
Each gene=length of DNA
DNA =long , coiled molecule formed from the two strands
Strands =twisted in a double helix
Genome =all the DNA in an organism
Nucleus=contains chromosomes
Weak hydrogen bonds = are between the bases they hold DNA strands together
Two strands of the double helix=joined by pairs of bases:4 different bases in DNA =
A =adenine
T=thymine
C=cytosine
G=guanine
Bases form complementary pairs:
A always pairs with T
C always pairs with G
What is DNA What is a chromosome What does the chromosome contain What is a nucleus What does the nucleus contain What is a gene What is a double helix What are the two strands of the double helix joined by What are the 4 different bases in DNA called What do they each join with What is a genome What hold the DNA strands together
DNA
DNA as a polymer
DNA=polymer made of many monomers called nucleotides , joined together
Base can be A C T G
DNA from a fruit:
DNA Can be extracted from a fruit by:
- grinding the fruit with sand , using a pestle and mortar , to separate the cells
- adding a detergent to break open the membranes
- adding ice cold alcohol so that the DNA precipitates out
Describe DNA as a polymer
What can the bases be on this structure
How an DNA be extracted from a fruit
Generic terms
Gametes=sex cells
Nucleus =contains chromosomes
Zygote=
Phenotype=characters are produced, including what the individual looks like
Genotype=shows allele (forms of genes) in the individual
Gene=section off DNA
Allele =
Chromosomes=
Heterozygous=different alleles of same gene
Homozygous=same allele on both Chromosomes
Dominant=dominant allele will show when at least one copy is present in the genotype
Recessive=allele will only show when two copies are present in the genotype
What is a gamete What is a gene What is an allele What does dominant mean Wheat does recessive What does homozygous mean What does heterozygous mean What does genotype mean What does phenotype mean What does zygote mean
Monohybird inheritance
=can be explained song gentic diagrams and punnet squares
Genetic diagrams and punnet square
=Only show only possible offspring , not the actual offspring from these parents
Punnet square
Different way of showing same information about how genotype is inherited and what effect this has on phenotype
What does monohybird inheritance Mean
What does genetic diagram mean
What does punnet square mean
What does genetic diagram mean
Family pedigrees
Cystic fibrosis(CF)= genetic condition caused by a recessive allele .
Pedigrees analysis=can be used to study the inheritance of dominant and recessive alleles
Family pedigree =show inheritance of a genetic condition within a family and to predict the chance that someone will inherit the faulty allele
What did family pedigree show
What does CF mean
What does pedigree analysis mean
How can u calcite outcomes from pedigree analysis
Sex determination
Genetic diagrams and punnet square=sex humans is determined at fertilisation and can be expressed using genetic diagrams and punnet squares
Sex chromosomes=sex of humans is controlled by one pair of sex chromosomes
Genotype XX =produces female phenotype
Genotype XY= produces male phenotype
Genotype and phenotype
Genotype=all the genes of the individual
Phenotype =what individual looks like
Genetic diagram and punnet square
=used to that the sex of an individual is determined at fertilisation
What do genetic diagrams and punnet square show
What is a sex chromosome What does genotype XX produce What does genotype XY produce What is a genotype What is a phenotype What does genetic diagrams and punnet square show
Variation and mutation
Variation =
Mutation\genetic variation =created if the sequence of bases in a gene is changed
Causes of variation:
Causes of variation that influence phenotype include genetic variation and environmental variation
*generic variation happens through mutation
*phenotype results in combination of different alleles for different genes
This combination of alleles that an organism inherits is the result of sexual reproduction
- most variation=caused by a combination of genes and environment
- most phenotypic features in humans(e.g, hair colour) are causes by genes
Mutation
-can affect the phenotype of an organism
-if the amino acid sequence is altered ,activity of the protein produced may also be altered
However:
-most genetic mutations have no effect on the phenotype
-some mutations have a mall effect on a phenotype
-single mutation can , rarely , significance affect the phenotype
Mutation may cause:
- large change in the protein produced
- small change in the protein
- no change at all in the protein produced
*the bigger the hangs to the protein=larger the effect on how the body works
What does variation mean What does mutation mean What do causes of variation influence ? How does genetic variation happen ? What does phenotype result in How is most variation caused What are most phenotype features caused by What can mutation effect ... what can mutation cause What does it mean if the protein is bigger
Human genome project
HGP=collaboration between scientists to decode the human genome(the order of bases on a human chromosomes)
- the HGP was completed quickly because so many scientists worked on it at the same time.
- the work was published in 2003 and made freely available to scientists all over the world
- the results are being used to develop new medicines and treatments for disease
Advantages and disadvantages of the HGP
Advantages:
- alerting people that they are at particular risk of certain disease
- distinguishing between different forms of diseases
- allowing doctors to tailor treatments for some disease to the the individual;where specific alleles affect how a person will respond to treatment
Disadvantages:
- People who at risk of certain diseases e.g, cancer may have to pay more to obtain life insurance
- -it may not be helpful to tell someone they are at risk of a condition for which there is currently no cure
What does HCP mean Why was it competed quickly When was their work published What are their results being used for What are the advantages of the HGP what are the disadvantages of HGP
Evolution
Charles Darwin developed=theory of evolution of natural selection -still important in modern biology
Who developed the theory of evolution ?
What is natural selection ?
Huma evolution
What is human evolution
Classification
What is classification Who proposed the five Kingdom system Describe it What is the three domain system Describe it
