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Studied by 10 peopleCELLS
Here's your reformatted flashcard-style set with separate cards for extra information, all directly based on your slideshow:
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### DNA
DNA: Deoxyribonucleic acid; provides instructions for cells to construct specific proteins.
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### Nucleotide
Nucleotide: The monomer of DNA, made of:
* Phosphate group
* Deoxyribose sugar
* Nitrogenous base
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### DNA Structure
Double Helix: The structure of DNA made of two antiparallel strands twisted around each other.
Sugar-Phosphate Backbone: Strong phosphodiester bonds form the sides of the DNA ladder.
Nitrogenous Base Pairs: Held together by weaker hydrogen bonds in the centre of the DNA molecule.
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### Base Pairing
Complementary Base Pairing:
* Adenine (A) pairs with Thymine (T) — 2 hydrogen bonds
* Cytosine (C) pairs with Guanine (G) — 3 hydrogen bonds
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### Gene
Gene: A sequence of DNA that codes for a protein.
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### Chromosome
Chromosome: Long strands of DNA wrapped around histone proteins; carries many genes.
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### Chromosome Structure
* Telomere: Protective repetitive base sequences at chromosome ends
* Centromere: Holds two sister chromatids together
* Sister Chromatids: Identical strands formed by DNA replication
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### Autosome
Autosome: One of the 22 pairs of chromosomes that are not involved in determining sex.
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### Sex Chromosome
Sex Chromosome: The 23rd pair of chromosomes determining biological sex.
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### Sex Chromosome Pairs
* Female: XX
* Male: XY
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### Gene Relationships
Gene, DNA, Chromosome Relationship:
* Genes are made of DNA
* DNA is coiled into chromosomes
* Genes are located at specific loci on chromosomes
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### Somatic Cell
Somatic Cell: Body cell (e.g. skin, muscle); diploid with 46 chromosomes.
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### Gamete
Gamete: Sex cell (sperm or egg); haploid with 23 chromosomes.
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### Diploid
Diploid (2n): Cell with two sets of chromosomes (46 in humans).
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### Haploid
Haploid (n): Cell with one set of chromosomes (23 in humans).
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### Cell Division Purpose
1. Growth and Development: New cells form to build the body.
2. Cell Replacement: Damaged or dead cells are replaced (e.g. skin).
3. Asexual Reproduction: Some organisms reproduce by creating identical offspring.
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### Mitosis
Mitosis: Nuclear division that produces two identical diploid somatic cells.
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### Steps of Mitosis
* Prophase: Chromosomes condense, spindle forms, nuclear membrane breaks.
* Metaphase: Chromosomes line up in the centre.
* Anaphase: Sister chromatids separate to opposite poles.
* Telophase: Nuclear membranes reform.
* Cytokinesis: Cytoplasm splits, forming two identical cells.
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### Meiosis
Meiosis: Cell division in gametes producing four genetically different haploid cells.
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### Steps of Meiosis
* Crossing Over: Exchange of genetic material in Prophase I
* Independent Assortment: Random arrangement of chromosomes in Metaphase I
* Result: Four unique haploid cells
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### Mitosis vs Meiosis
| Feature | Mitosis | Meiosis |
| -------------- | ------------------- | ----------------------- |
| Cell type | Somatic (body) | Gonads (gametes) |
| # of divisions | One | Two |
| Daughter cells | 2 identical diploid | 4 non-identical haploid |
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### Diploid/Haploid at Stages
* Mitosis: Starts diploid → Ends diploid
* Meiosis: Starts diploid → Ends haploid
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### Nondisjunction
Nondisjunction: Failure of chromosomes to separate during meiosis, causing aneuploidy.
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### Trisomy
Trisomy: A condition where an individual has three copies of a chromosome (e.g. Down Syndrome = Trisomy 21).
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### Monosomy
Monosomy: A condition where an individual has only one copy of a chromosome (e.g. Turner Syndrome).
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### Karyotyping
Karyotyping: Visual layout of chromosomes to check number, size, and structure.
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### Genetic Conditions
* Down Syndrome: Extra chromosome 21
* Turner Syndrome: Only one X chromosome in a female
* Klinefelter’s Syndrome: XXY in males
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### Genetics
Genetics: The study of heredity and how traits are passed on.
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### Gregor Mendel
Gregor Mendel: Discovered basic inheritance using pea plants; father of genetics.
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### Dominant Trait
Dominant Trait: Represented by a capital letter; expressed if present in the genotype.
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### Recessive Trait
Recessive Trait: Represented by a lowercase letter; only expressed if both alleles are recessive.
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### Genotype
Genotype: The alleles present for a trait (e.g. BB, Bb, bb).
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### Phenotype
Phenotype: The physical expression of a genotype (e.g. brown eyes).
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### Allele
Allele: A different version of a gene (e.g. B for brown eyes, b for blue eyes).
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### Homozygote
Homozygote: Two identical alleles at a gene locus (BB or bb).
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### Heterozygote
Heterozygote: Two different alleles at a gene locus (Bb).
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### Homologous Chromosomes
Homologous Chromosomes: Pairs of chromosomes with the same genes at the same loci.
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### Monohybrid Cross
Monohybrid Cross: A genetic cross involving one trait to predict genotype and phenotype ratios.
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### Punnett Square
Punnett Square: A grid used to determine possible allele combinations in offspring.
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### Sex-Linked Traits
Sex-Linked Traits: Traits controlled by genes on sex chromosomes, usually the X.
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### Colour Blindness
Colour Blindness: X-linked recessive trait; expressed in males who inherit the affected X.
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### Haemophilia
Haemophilia: X-linked recessive disorder; more common in males.
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ChatGPT said:
You're absolutely right — thank you for catching that! Here are the missing flashcards on the Cell Cycle, based entirely on your slideshow content:
Cell Cycle
Cell Cycle: The series of events a cell goes through to grow, replicate its DNA, and divide, producing two genetically identical daughter cells.
Stages of the Cell Cycle
Interphase: The longest phase of the cell cycle, including three stages:
G1 (Gap 1): Cell grows, organelles duplicate, proteins for DNA replication are made.
S (Synthesis): DNA replication occurs, chromosomes duplicate to become double-stranded.
G2 (Gap 2): Cell grows again, and proteins are synthesised in preparation for mitosis.
Cell Cycle Checkpoints
G1 Checkpoint: Checks if the cell is the correct size, has enough proteins, and undamaged DNA.
G2 Checkpoint: Ensures DNA was correctly replicated and the cell is ready for mitosis.
G0 Phase
G0 Phase: A resting stage where cells do not divide. Some cells (like nerve cells) remain in G0 permanently.
Binary Fission
Binary Fission: The process by which prokaryotic cells (e.g. bacteria) divide. Steps include:
DNA replication
Elongation
Septum formation
Cell division