Plant Cell Structure and Bacterial Composition

This page continues the exploration of cell structures, focusing on plant cells and bacteria. It's an essential part of Cell Biology notes GCSE AQA and provides crucial information for GCSE Biology notes pdf.

Plant Cell Structure: Plant cells share many similarities with animal cells but have some unique features:

• Additional organelles: chloroplasts and vacuoles
• Cell wall made of cellulose

Definition: Chloroplasts are organelles responsible for photosynthesis in plant cells. They contain thylakoids, which are disc-shaped structures containing chlorophyll.

The page provides a detailed description of chloroplast structure:

• Double membrane
• Thylakoids arranged in stacks called grana
• Fluid-filled stroma surrounding the thylakoids

Vocabulary: The tonoplast is the membrane surrounding the vacuole in plant cells. The vacuole contains cell sap, which is a mixture of water, sugar, and minerals.

Bacterial Cell Composition: Bacteria, as prokaryotic organisms, have a simpler structure compared to eukaryotic cells:

• No nucleus - DNA exists as a single loop and plasmid
• No membrane-bound organelles
• Smaller ribosomes and mesosomes for respiration
• Cell wall made of peptidoglycan/murein
• Some bacteria have additional structures like capsules and flagella

Highlight: The bacterial cell wall, composed of peptidoglycan, is a key structural difference between prokaryotic and eukaryotic cells. This is important when considering the 10 difference between prokaryotic and eukaryotic cell.

The page also briefly touches on virus structure, which includes:

• Genetic material (DNA or RNA)
• Protein coat (capsid) and lipid coat
• Attachment proteins

This comprehensive overview of plant, bacterial, and viral structures is crucial for understanding the Difference between prokaryotic and eukaryotic cell PDF and prepares students for Combined Science Biology Paper 1 revision notes.

Chromosomes and Genetic Material

This final page of the Cell Biology revision notes PDF focuses on chromosomes and genetic material, which are fundamental concepts in biology and essential for understanding inheritance and cell division.

Key points covered:

1. Chromosome structure:
   • Coiled form of DNA
   • Formed during interphase of cell division (mitosis/meiosis) in animals and plants
   • Composed of two identical sister chromatids joined by a centromere

Definition: A chromosome is a structure of coiled DNA that carries genetic information in a cell. It becomes visible during cell division when the DNA is tightly packed.

2. Homologous pair of chromosomes:
   • Consists of one maternal chromosome (from the mother) and one paternal chromosome (from the father)
   • Carries the same genes but may have different alleles

Vocabulary: Alleles are different versions of the same gene. For example, the gene for eye color may have alleles for blue eyes or brown eyes.

This information is crucial for understanding both Sexual and asexual reproduction in biology examples and the genetic basis of inheritance. It helps explain why offspring from sexual reproduction have a mix of traits from both parents, while those from asexual reproduction are genetically identical to the parent.

Highlight: The concept of homologous chromosomes is fundamental to understanding meiosis and sexual reproduction. It explains genetic variation in offspring and is a key Difference between sexual and asexual reproduction.

This page provides essential knowledge for students studying Sexual and asexual reproduction in biology notes and prepares them for questions about genetic inheritance and cell division in their GCSE Cell Biology exam questions and answers pdf.