Cells And Genes Flashcards
What are the organelles of an animal cell?
Nucleolus Nucleus Ribosome Vesicle RER Golgi apparatus Cytoskeleton SER Mitochondria Vacuole Cytoplasm Lysosome Centriole
What organelle do cells with high energy requirements e.g. muscle and liver cells have a lot of?
Mitochondria
What organelle do cells that secrete protein e.g. pancreatic cells, have a lot of?
RER
Golgi apparatus
What are the stages of the cell cycle?
G0: resting/quiescent G1 (cells can enter here from M or G0) S phase: DNA replication G2 M: nuclear + cytoplasmic division (mitosis)
What are chromosomes?
Structures that contain our genetic material that are made of chromatin (DNA + histones that package + condense the DNA)
Explain the phases of mitosis.
- Interphase (G2): cell at rest
- Prophase: nuclear membrane breaking down, chromosomes condensing + centrosomes migrating to opposite poles of cell producing spindle fibres
- Prometaphase: nucleus dissolved, centrosomes at poles, chromosomes attach to spindle fibres along with kinetochore
- Metaphase: all chromosomes lined up in middle attached to spindle fibres with all kinetochores
- Anaphase: sister chromatids pulled apart
- Telophase: reestablishment of nuclei containing genetic material + cytoplasm starting to split at cleavage furrow
- Interphase (G1): 2 cells made
What are cellular adaptations?
Reversible changes in cells in response to changes in the environment as a result of physiological or pathological conditions
What changes can cells undertake when adapting?
Number
Size
Cell type
The way that cells adapt depends partly on:
Their ability to divide
Define hyperplasia.
Increase in no. of cells in a tissue (cells must be able to divide to do this)
Define hypertrophy.
Increase in cell size involving an increase n cellular contents as well as swelling (all cells)
Define atrophy.
Reduction in cell size involving internal digestion of cellular contents (autophagy)
Define metaplasia.
Reversible change from one cell type to another (usually in epithelia; can develop into cancer)
Why is genetics important?
Humans have ~20,000 genes encoding RNA + protein with diverse biochemical functions; many gene products regulate other genes
Genes contribute to every biological feature in healthy + diseased states (many have profound effects during embryonic development)
___ people under the age of 25 will develop a disease with a significant genetic component.
1 in 20
What is the genome?
Complete haploid set of genetic material in an organism (3x10^9 DNA base pairs in humans)
What is a karyotype?
Humans normally have 23 pairs of chromosomes:
- 22 pairs of autosomes
- 1 pair of sex chromosomes (XX = females, XY = males)
What are genes?
Segments of DNA within the genome that encode RNA + usually protein which make up our genotype
What is a Punnett square?
Simple grid used to draw expected outcomes of matings; it can be used to predict the probability that a new individual will have a particular genotype
How are Punnett squares used?
Genotype of 1 parent written along top of square
Genotype of other parent written down side of square
= 4 possible genotypes resulting from mating are drawn in grid
What factors make up a persons phenotype?
Anatomy, physiology + psychology
Which can be influenced by GENOTYPE + ENVIRONMENT (changes over time due to environmental factors)
What does it mean to be genetically susceptible to a disease?
It does not mean a person will necessarily develop the disease but is at an increased risk
What are alleles?
If different versions of a gene exist in a population, the gene is polymorphic + different versions are called alleles
What is a wild type gene?
Allele that is most common in a population usually not associated with disease
What is the difference between homozygous and heterozygous chromosomes?
Chromosomes are arranged in pairs so there are 2 copies of each gene in an individual; they can either be identical (homozygous) or different (heterozygous)
What so dominant, co-dominant and recessive alleles do?
Dominant alleles determine phenotype over recessive alleles whereas co-dominant alleles jointly determine phenotype
Give an example of dominance and co-dominance.
ABO blood grouping:
- A + B alleles co-dominant with respect to eachother
- A + B alleles dominant with regard to O allele
- O allele recessive with respect to A + B alleles
Using a Punnett square, work out the potential outcomes of the offspring if both parents are AB blood group.
A B
A AA AB
B AB BB
Offspring will either be A (25%), AB (50%) or B (25%)
How are genes, proteins + phenotype related?
Genes related to phenotype via genetics
Genes related to proteins via molecular biology
Proteins related to phenotype via biochemistry
Phenotype = function
