Cell Structure, Function & Asexual Reproduction in Unicellular Organisms

What is a prokaryote?

A cell without a nucleus

What is the hierarchy of biological organisation from simple to complex?

It is the arrangement of biological structures:

Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organism

What are tissues?

Groups of similar cells working together for a specific purpose

What are organs?

Structures made of different tissues collaborating to perform complex functions

What are organ systems?

Groups of organs that work together to carry out major body function

What is a eukaryote?

A cell with a nucleus

What is an example of a prokaryote?

A bacterium

What is an example of a eukaryote?

Plants and Animals

Which is the smaller/simpler cell: Prokaryotic or eukaryotic cells?

Prokaryotic cell

Which type of cell is unicellular, and which is multicellular?

Prokaryotes are unicellular, and eukaryotes are (usually) multicellular

What is the difference between the cell division of prokaryotes and eukaryotes?

Prokaryotes divide by binary fission, but eukaryotes divide by mitosis or meiosis

What is the difference between the reproduction of prokaryotes and eukaryotes?

Prokaryotes reproduce asexually, while eukaryotes reproduce either asexually or sexually

What does DNA stand for?

Deoxyribonucleic acid

What are 3 common methods of asexual reproduction in unicellular organisms?

Binary fission, budding, sporulation

Which organisms carry out binary fission?

Prokaryotes (like bacteria)

Which organisms carry out budding?

Eukaryotes (like yeast and hydra)

What is sporulation?

A common form of asexual reproduction in some protists, fungi, and plants where parent cells divide to produce many cells called spores, which develop into organisms identical to the parent.

Where are spores held in some fungi?

Sporangium

What are the steps of binary fission? (Explain it) (3 pts)

1. The parent cell carries out DNA replication (copies DNA strands)

2. Chromosome segregation - Each strand moves to the two ends of the parent cell

3. Cytokinesis - The cell splits to form 2 identical daughter cells

Explain budding.

An outgrowth from the cell appears, enlarges, and is cut off as an independent cell.

What happens when budding occurs rapidly?

The daughter cells do not separate immediately, therefore groups of attached buds/cells can sometimes be seen

How is yeast helpful? List three reasons.

Fermentation
Bread making
Production of antibiotics

What is the formula of fermentation?

C₆H₁₂O₆ → 2CO₂ + 2C₂H₅OH + 118kJ

How is yeast harmful. State one way.

Yeast infection

Study prokaryote diagrams.

Ok🫡

What are organelles?

The smaller particles within a cell

What is the cell membrane?

The thin outer layer that surrounds and protects the cell

What makes up the cell membrane?

2 layers of phospholipid molecules, also known as a phospholipid bilayer

Why is phosphate hydrophilic in phospholipids?

Phosphate is negatively charged, therefore it can mix with water, making that part of phospholipid water-loving.

Why is lipid hydrophobic in phospholipids?

They are non-polar (have no charge), so they cannot dissolve in water

What do the cholesterol molecules do?

Help to keep the cell membrane fluid

What are membrane proteins for?

Transporting substances across the cell membrane

Explain the permeability of the cell membrane.

It is selectively permeable (semi-permeable), meaning it only allows some substances to pass through its walls

What is the cytoplasm?

A jelly-like substance found inside the cell

What happens in the cytoplasm?

Chemical processes essential to life are carried out

What is metabolism?

All chemical reactions that occur within cells to maintain life

What is the nucleus?

The information center of the cell

What are the three parts of the nucleus?

Nucleolus, nuclear membrane, nucleoplasm

What does the nucleolus do?

Contain the ribonucleic acid (RNA) which is important for making proteins

What does the nuclear membrane do?

It has pores that allow materials to pass back and forth between the nucleus and the cytoplasm (and keeps out foreign materials)

What does the nucleoplasm do?

Contain chromosomes that store instructions for all cell functions

What is the function of the golgi body/apparatus?

Storing and releasing substances made by cells

What do ribosomes do?

Make proteins

What do proteins do for the cell?

Build the cell and keep it in good repair

What does the endoplasmic reticulum do?

Transport and store substances around the cell

What are the two types of endoplasmic reticula (ER) and what makes them different?

They are rough or smooth. Rough ER has ribosomes attached to them, but smooth ER doesn’t

What is the mitochondrion?

A sausage-shaped structure of the cell that produces energy in the form of adenosine triphosphate (ATP) through cellular respiration

What does ATP stand for?

Adenosine triphosphate

What is the fluid in the mitochondria called?

Matrix

Describe the two membranes of mitochondria.

The outer membrane covers the mitochondrion, and the inner membrane folds over many times and creates layered structures called cristae.

What do centrioles and microtubules do?

Assist in cell division (reproduction)

What does the lysosome do?

Protects the cell by destroying bacteria, other unwanted particles, or worn-out and damaged organelles.

What does the vacuole do?

Stores food materials

What is the difference between the vacuole of an animal and plant cell?

They are small and may not be permanent in animal cells, and are large and central in plant cells

What does the cell wall do?

Allow water and dissolved substances to pass through, and keeps the structure of the cell (it is fully permeable)

What makes up the plant cell wall?

Cellulose

What are plastids?

It is a small sac containing a chemical substance (chlorophyll in plant cells) or food substances (like starch)

What are chloroplasts?

A type of plastid that contains the green pigment chlorophyll which absorbs sunlight. This is the site of photosynthesis.

What do plant vacuoles have?

Cell sap, which contains salts, sugars, and pigment dissolved in water

Study the structures of plant and animal cells.

Ok🫡

State 5 organelles only found in special cells.

Cell wall, chloroplasts, storage granules, flagellum, cilia

What are storage granules?

Small particles in the cytoplasm that store carbohydrates (like starch in plants and glycogen in animals)

What is a flagellum?

A long whip-like structure that allows movement

What are cilia?

Short microscopic hairs that beat in a wave-like manner to move a cell or push substances across its surface

What are adaptations of muscle cells? List 3.

• Long and thin to be packed closely together with others

• Contains numerous mitochondria to provide the energy for contractions

• Contains contractile proteins so that cells can shorten

What are the 4 basic types of tissues?

Epithelial tissue, Muscle tissue, Connective tissue, Nervous tissue

What does epithelial tissue do?

Creates protective boundaries

What does the connective tissue do?

Supports the body or links body parts together

What does the muscle tissue do?

Causes movement by flexing and twisting

What does the nervous system do?

Coordinates different parts of the body via fast electrical and chemical signals