SWOT Notes Biology+Forces and Motion

Testes

produce sperm

Scrotum

aa pouch of skin containing the testicles.

Sperm Ducts

Carry sperm from the testes to the penis

Prostate Gland

a gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid.

Urethra

tube that carries urine from the bladder to the outside of the body

Penis

Male reproductive organ

Ovaries

Glands that produce the egg cells and hormones

Oviducts

Passageway that moves eggs away from the ovary and towards the uterus; usual site of fertilization

Uterus

Female organ of reproduction used to house the developing fetus.

Cervix

The opening to the uterus

Vagina

A muscular, elastic passageway that extends from the uterus to the outside of the body

Gametes

reproductive cells

What happens to gametes during fertilisation?

They join to restore the normal number of chromosomes

Describe the development from a zygote to an embryo and then a foetus.

The development from a zygote to a fetus involves fertilization, cell division, implantation, organ formation in the embryonic stage (weeks 2-8), and growth and maturation of the fetus until birth at full term (around 40 weeks).

Haploid

having a single set of unpaired chromosomes

Diploid

containing two complete sets of chromosomes, one from each parent.

State the location of DNA/genes in a cell.

DNA is located within chromosomes in the nucleus of a cell.

DNA structure

DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine

Explain what the human genome is

The human genome is the entirety of an individual's genetic material encoded in DNA, comprising all genes and non-coding sequences across 23 pairs of chromosomes, and it provides the instructions for the development, functioning, and characteristics of a human being.

Explain the importance of DNA making exact copies of itself

The accurate replication of DNA is crucial as it ensures the faithful transmission of genetic information during cell division, maintaining genetic stability and allowing for the inheritance of traits from one generation to the next.

Give three examples of mutations

Substitution mutation, Insertion mutation, Deletion mutation

Causes of genetic mutations

Radiation, Chemical Agents, Viruses,

How are mutations useful

More variation

How are mutations harmful

if it reduces the organisms chance for survival and reproduction

Genotype

genetic makeup of an organism

Phenotype

physical characteristics of an organism

Cell

The basic unit of structure and function in living things

Allele

Different forms of a gene

Characteristic

trait

Dominant

An allele that is always expressed

Recessive

An allele that is masked when a dominant allele is present

Explain how Punnett squares can be used to show how genes are inherited.

Punnett squares demonstrate how alleles from two parents combine to predict the genotypes and phenotypes of their offspring, illustrating the principles of inheritance for specific traits.

Variation

a difference between individuals of the same species

What causes variation?

Genetic causes, environmental cause or a combination of both genes and the environment.

Discrete variation

in genetics, inherited traits that have a limited number of variations, such as the ability or inability to roll one's tongue

Continuous variation

range of small differences in a shared trait. Human height

Process of mitosis

Mitosis is a cell division process where a single cell duplicates its DNA, divides into two identical daughter cells, each containing a complete set of chromosomes.

Process of meiosis

Meiosis is a specialized cell division process that produces four genetically unique haploid daughter cells, each with half the number of chromosomes as the parent cell, through two rounds of division.

Evolution

The gradual change in a species over time

Selective breeding

the human practice of breeding animals or plants that have certain desired traits

Examples of selective breeding

1. To produce crops with disease resistance

2. To produce animals which produce more meat or milk

3. To produce domestic dogs with a gentle nature

4. To produce large or unusual flowers

Darwin presented an idea about evolution by natural selection. What were the key points of this idea?

Darwin's idea of evolution by natural selection proposed that variation exists within populations, those variations can lead to differences in survival and reproduction, and over time, individuals with advantageous traits are more likely to survive and pass on their traits to future generations, driving the gradual change of species over time.

Why is variation important in terms of natural selection.

Variation is crucial in natural selection as it provides the raw material for evolutionary change, allowing for adaptation to changing environments and driving the process of species diversification.

Diversification in natural selection

the process by which species evolve and differentiate into a variety of forms, often in response to environmental factors, leading to increased biological diversity within ecosystems.

Fitness

how well an organism can survive and reproduce in its environment

Scientific Theory

a well-tested concept that explains a wide range of observations