Biology Exam Flashcards pt. 2

What is water used for in plants?

Cooling, photosynthesis, support, transporting minerals + sugar.

What is the function of the roots?

roots absorb water and minerals through root hairs

How are water and minerals transported into root hairs

Osmosis

What is the function of xylem?

carries water and minerals to from the roots to the rest of the plant

How are is xylem supported

Lignified with rings of lignin which allow xylem to withstand changes in pressure as water moves through the plant.

What is the function of phloem?

Transports sugar that is made during photosynthesis in the palisade mesophylll cells of the leaves

What direction does phloem move

up and down

Vein (leaf)

Contains xylem and phloem to allow transport of sugar away from leaves

Mesophyll cells

Have lots of chloroplasts for photosynthesis

What are the two types of mesophyll cell?

Palisade + Spongy

Stomata

Pores found in the lower epidermis of the leaf that allow CO2 to enter + allow water and O2 to leave.

Guard cells

Change shape to open or close stomata

Upper epidermis

Top of the leaf

Lower epidermis

Bottom of leaf

How does the stomata open?

- When a plant has a high level of water the guard cells are turgid making them curve out. - The stoma then opens to allow the CO2 in and the O2 + Water out.

How does the stomata close?

- When the plant has a low level of water, the guard cells are plasmolysed and close.
- Gas exchange cannot take place + water is not lost

What is transpiration?

the process of water moving through a plant (starting from the roots) and its evaporation through the stomata.

Describe the 3 stages of transpiration

What is an ecosystem?

All organisms living in a habitat + nonliving components that they interact with

Food Web

Food webs show all the feeding interactions between producers and consumers within an ecosystem

Niche

The role an organism plays within a community

What does a niche relate to?

A nice relates to the resources that organisms need in their ecosystems and their interactions with others in their community

What are some examples of interactions that an organism may have?

Predation, Competition, Conditions needed to survive

Predation

occurs when an organism is eaten by another

Conditions needed to survive

organisms can only survive in certain temperatures

Competition

occurs when there are a lack of available resources

What is competition?

Competition is when two or more organisms need the same resource but the resource is in short supply

Examples of things organisms may compete over

Light, Water, Food

What are the two types of competion

Interspecific, Intraspecific

Interspecific competition

Competition between members of different species for one or a few of the resources that they need.

Intraspecific competition

competition between members of the same species for all resources needed

What is absorption?

When oxygen + nutrients from food are absorbed into the bloodstream to be delivered to cells for respiration

What structure in tissues allows materials to be exchanged between the blood and cells

Capillaries

Name the 3 features which increase the efficiency of absorption

- Large surface area
- Thin walls
- Extensive blood supply

What does the alveoli do?

increases surface area for gas exchange

How does oxygen move through the alveoli?

Oxygen enters the alveoli + is absorbed through the thin wall into the blood capillaries

How does CO2 moves through the alveoli?

CO2 leaves the blood capillaries + is absorbed through the thin wall into the alveoli

What is carbohydrate broken down into?

Glucose

What is fat broken down into?

fatty acids and glycerol

What is the function of the villi?

There are a large number of Villi that line the small intestine in order to give it a larger surface area for absorption

What do the blood capillaries absorb?

amino acids and glucose

What does the lacteal absorb?

fatty acids and glycerol

What is the function of blood?

Transports oxygen, carbon dioxide + nutrients around the body

In mammals the blood contains...

plasma, red blood cells, white blood cells

What do RED blood cells do?

carry oxygen around the body

What are some features of red blood cells?

- Contains haemoglobin to bind to O2 molecules
- Has no nucleus to provide more space for haemoglobin
- Is a Biconcave shape to increase surface area

Where is oxygen diffused into the blood?

Lungs

What is haemoglobin?

A protein that binds to oxygen to form oxyhaemoglobin

What do white cells do?

The are part of the immune system and they destroy pathogens

Pathogen

disease causing micro-organism

Examples of pathogens

bacteria, viruses, fungi

What is the function of an artery?

Arteries pump blood at a high pressure AWAY from the heart to the rest of the body.

Structural features of an artery

- Has a narrow central channel
- Thick muscular wall to withstand high pressure

What is the function of a vein?

Veins carry blood TOWARDS the heart

Structural features of

Controlled by a single gene

single gene inheritance

controlled by many genes

polygenic inheritance

What is discrete variation?

Differences in characteristics controlled by one single gene. Measurements fall into distinct groups.

Examples of discrete variation

Dry/Wet Ear wax, Earlobe shape, Long + short hair in cats

What is continuous variation?

Differences in characteristics controlled by more than one gene. There are a range of values between a min and max in continuous characteristics (also known as polygenic inheritance)

Examples of polygenic inheritance

Height, Fingerprint type

P1

The parent generation

F1

The first generation of offspring

F2

The second generation of offspring

What is the function of a monohybrid cross?

Predicts the offspring from two parents

An individual that has inherited two of the same allele

homozygous

An individual that has inherited 2 different alleles of the same gene

heterozygous

What is a genotype?

an individuals alleles for a specific characteristic

What is a phenotype?

Physical appearance based on the genotype for a specific characteristic

Why is the predicted phenotype of the offspring not always what you achieve in crossbreeding

Because inheritance is random

Animal cell ultrastructure

cytoplasm, mitochondrion, nucleus, ribosome, cell membrane

Plant cell ultrastructure

cell wall, cytoplasm, mitochondrion, nucleus, ribosome, cell membrane, vacuole, chloroplasts

Fungal cell ultrastructure

nucleus, mitochondrion, cell membrane, ribosome, mitochondrion, cytoplasm, cell wall, vacuole

Bacterial cell ultrastructure

plasmid, cell membrane, ribosomes, cell wall, cell membrane, circular chromosome

What is the Nucleus' function?

contains genetic information and controls cell activities

What is the Plasmid' function?

A small ring of genetic material found in bacterial cell

What is the cell membrane' function?

a selectively permeable membrane that controls what goes in and out of the cell

What is the cytoplasm' function?

stores the cells organelles and is the site for chemical reactions

What is the cell wall' function?

outer layer of the cell that helps support it

What is the chloroplast' function?

makes carbohydrates in green plant cells using light energy in photosynthesis

What is the mitochondria' function?

the main site of ATP production in aerobic respiration in cells

What is the vacuole' function?

membrane bound sac that stores nutrients(water, salts and sugars) in cells

What is the ribosome' function?

the site of protein synthesis

1mm\=\__________μm

1000

The cell wall in plant cells is made up of \____________ molecules

cellulose

The cell membrane is made up of...

phospholipids + proteins

the cell membrane is \______________ permeable

selectively

What is active transport?

movement of molecules across a cell membrane against a concentration gradient with energy

What is passive transport?

The movement of materials across the cell membrane down a concentration gradient without energy

examples of passive transport

diffusion and osmosis

What is diffusion?

the movement of molecules from high to low concentration

What is osmosis?

the diffusion of water across a selectively permeable membrane from an area of high concentration to low concentration

Why is diffusion important?

needed to diffuse nutrients and food for broth and for respiration

If the water concentration outside an animal cell is higher than inside...

water passes in and it can burst

If the water concentration outside a plant cell is higher than inside...

water will pass in and it will become turgid

If the water concentration outside an animal cell is lower than inside...

water passes out and the cell shrinks

If the water concentration outside a plant cell is lower than inside...

water passes out and it becomes plasmolysed

describe the structure of dna

a double stranded held by complimentary base pairs

what does dna do?

Stores genetic information and codes for protein

What are the four DNA bases?

Adenine, Thymine, Guanine, Cytosine