genetics

describe the structure of DNA

describe the structure of DNA

base pairs (A,T,C,G)

sugar

phosphate

these all make a nucleotide

discuss the advantages and disadvantages of using models in Science.

advantage = it can simplify complex systems

disadvantage = they can be misinterpreted

what is a gene?

A gene is a segment of DNA that contains the instructions for building and maintaining an organism's cells, tissues, and organs.

Genes are the basic units of heredity and are responsible for the transmission of traits from parents to offspring.

They code proteins, which perform various functions in the body.

what is a trait in genetics?

A trait in genetics is a specific characteristic or feature of an organism that is determined by its genetic makeup. They are influenced by genes, which are segments of DNA, and can be inherited from parents to offspring.

what is a chromosome?

A chromosome is made of DNA and proteins that contains genetic information. Humans typically have 46 chromosomes, arranged in 23 pairs.

what is a karyotype

A karyotype is a visual representation of an individual's complete set of chromosomes, organized and displayed in pairs.

outline how genes control characteristics

Gene expression is the mechanism by which genes control traits. Gene expressions are the instructions on how to make proteins.

contrast the karyotypes of human males and females

males = XY chromosomes

females = XX chromosomes

identify some human characteristics that are genetically determined

eye color, freckles, and curly hair

outline the process of DNA replication.

The parent DNA unzips, bases pair with both loose ends to form two new strands.

explain the advantages of DNA replicating exactly

it ensures that each of the new cells receives its own copy of the DNA.

outline the process of meiosis.

Starts with a parent cell, that splits into half. During the first split the parent cell half their chromosomes for each of the new daughter cells. When the daughter cells split again, they replicate their chromosomes for THEIR daughter cells

split, half, split, same

• meiosis only happens in gametes (sex cells), and only occurs in sex organs

• meiosis is used in sexual reproduction

• PMAT, prophase, metaphase, anaphase, telophase.

outline the process of mitosis.

Start with a parent cell, which divide into two new daughter cells with the same number of chromosomes as the parent cell.

split, same

• mitosis happens in all body cells for growth and repair

discuss the importance of meiosis in the formation of gametes.

meiosis is essential for sexual reproduction and genetic variation.

explain how the sex of a baby is determined at fertilisation

it depends on what chromosome the sperm is carrying. The egg already has an X chromosome, so if the sperm has a Y chromosome they will make a XY pair, resulting in a boy. And a girl if the pair is XX.

describe the experimental procedures used by Gregor Mendel for his pea breeding experiment

1. Selection of Pea Plants: Mendel chose pea plants (Pisum sativum) with distinct traits (e.g., flower color, seed shape).

2. Cross-Pollination: He manually cross-pollinated plants by transferring pollen from one flower to another.

3. Control of Fertilization: To ensure controlled breeding, he removed the anthers from the flowers to prevent self-pollination.

4. Observation of Traits: Mendel observed the traits of offspring over generations, noting dominant and recessive patterns.

5. Statistical Analysis: He recorded data and analyzed the ratios of traits in the offspring, leading to his formulation of the laws of inheritance.

define the term dominant

refers to alleles, they are always capitalized. They can override everything apart from homozygous recessive alleles.

define the term recessive.

refers to alleles, they are always in lower case. They get over powered by dominant alleles, however when paired with another recessive they can.

define the term heterozygous

 is when the pair of alleles are different from each other (for example- Dd)

define the term homozygous

a pair of alleles that are the same (for example dd)

define the term phenotype

an individuals observable traits

define the term genotype

the genetic makeup of an organism

classify factors that are important in determining the features of an organism as either genetic or environmental -

Genetic Factors

• DNA and genetic makeup

• Inherited traits

Environmental Factors

• Climate and weather

• Nutrition and diet

describe examples that illustrate the role of environmental factors in determining the features of an organism -

succulents having water stores in their leaves.